USE IN SPECIFIC POPULATIONS SECTION.

8USE IN SPECIFIC POPULATIONS. 8.1 Pregnancy. Pregnancy Surveillance ProgramThere is pregnancy surveillance program that monitors pregnancy outcomes in individuals exposed to molnupiravir during pregnancy. The prescribing healthcare provider must document that pregnant individual was made aware of Merck Sharp Dohmes pregnancy surveillance program at 1-877-888-4231 or pregnancyreporting.msd.com. If the pregnant individual agrees to participate in the pregnancy surveillance program and allows the prescribing healthcare provider to disclose patient specific information to Merck Sharp Dohme, the prescribing healthcare provider must provide the patients name and contact information to Merck Sharp Dohme. Pregnant individuals exposed to molnupiravir can also report the exposure by contacting Merck Sharp Dohme Corp., subsidiary of Merck Co., Inc., Kenilworth, NJ USA at 1-877-888-4231 or pregnancyreporting.msd.com.Risk SummaryBased on animal data, molnupiravir may cause fetal harm when administered to pregnant individuals. There are no available human data on the use of molnupiravir in pregnant individuals to evaluate the risk of major birth defects, miscarriage or adverse maternal or fetal outcomes; therefore, molnupiravir is not recommended during pregnancy [see Box and Warnings and Precautions (5.1)]. In an animal reproduction study, oral administration of molnupiravir to pregnant rats during the period of organogenesis resulted in embryofetal lethality and teratogenicity at times the human NHC (N4-hydroxycytidine) exposures at the recommended human dose (RHD) and reduced fetal growth at >= times the human NHC exposure at the RHD. Oral administration of molnupiravir to pregnant rabbits during the period of organogenesis resulted in reduced fetal body weights at 18 times the human NHC exposure at the RHD (see Data). When considering molnupiravir for pregnant individual, the prescribing healthcare provider must communicate the known and potential benefits and the potential risks of using molnupiravir during pregnancy to the pregnant individual. Molnupiravir may only be prescribed to pregnant individual after the prescribing healthcare provider has determined that the benefits would outweigh the risks for that individual patient. If the decision is made to use molnupiravir during pregnancy, the prescribing healthcare provider must document that the known and potential benefits and potential risks of using molnupiravir during pregnancy were communicated to the pregnant individual [see Box]. There are maternal and fetal risks associated with untreated COVID-19 in pregnancy (see Clinical Considerations).The estimated background risk of major birth defects and miscarriage for the indicated population is unknown. All pregnancies have background risk of birth defect, loss, or other adverse outcomes. In the U.S. general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is to 4% and 15 to 20%, respectively.Clinical ConsiderationsDisease-associated maternal and/or embryo/fetal riskCOVID-19 in pregnancy is associated with adverse maternal and fetal outcomes, including preeclampsia, eclampsia, preterm birth, premature rupture of membranes, venous thromboembolic disease, and fetal death.DataAnimal DataIn an embryofetal development (EFD) study in rats, molnupiravir was administered orally to pregnant rats at 0, 100, 250, or 500 mg/kg/day from gestation days (GDs) to 17. Molnupiravir was also administered orally to pregnant rats at up to 1,000 mg/kg/day from GDs to 17 in preliminary EFD study. Developmental toxicities included post-implantation losses, malformations of the eye, kidney, and axial skeleton, and rib variations at 1,000 mg/kg/day (8 times the human NHC exposure at the RHD) and decreased fetal body weights and delayed ossification at >=500 mg/kg/day (3 times the human NHC exposure at the RHD). There were no developmental toxicities at <=250 mg/kg/day (less than the human NHC exposure at the RHD). Maternal toxicities included decreased food consumption and body weight losses, resulting in the early sacrifice of two of sixteen animals at 1,000 mg/kg/day, and decreased body weight gain at 500 mg/kg/day. In an EFD study in rabbits, molnupiravir was administered orally to pregnant rabbits at 0, 125, 400, or 750 mg/kg/day from GDs to 19. Developmental toxicity was limited to reduced fetal body weights at 750 mg/kg/day (18 times the human NHC exposures at the RHD). There was no developmental toxicity at <=400 mg/kg/day (7 times the human NHC exposures at the RHD). Maternal toxicities included reduced food consumption and body weight gains, and abnormal fecal output at 750 mg/kg/day.In pre- and post-natal developmental study, molnupiravir was administered orally to female rats at doses up to 500 mg/kg/day (similar to the human NHC exposure at the RHD) from GD6 through lactation day 20. No effects were observed in offspring. 8.2 Lactation. Risk SummaryThere are no data on the presence of molnupiravir or its metabolites in human milk. NHC was detected in the plasma of nursing pups from lactating rats administered molnupiravir (see Data). It is unknown whether molnupiravir has an effect on the breastfed infant or effects on milk production.Based on the potential for adverse reactions in the infant from molnupiravir, breastfeeding is not recommended during treatment with molnupiravir and for days after the final dose. lactating individual may consider interrupting breastfeeding and may consider pumping and discarding breast milk during treatment and for days after the last dose of molnupiravir [see Warnings and Precautions (5.1, 5.3)]. DataWhen molnupiravir was administered to lactating rats at >=250 mg/kg/day in the pre- and post-natal development study, NHC was detected in plasma of nursing pups.. 8.3 Females and Males of Reproductive Potential. Based on animal studies, molnupiravir may cause fetal harm when administered to pregnant individual.Pregnancy TestingPrior to initiating treatment with molnupiravir, assess whether an individual of childbearing potential is pregnant or not, if clinically indicated [see Warnings and Precautions (5.1)]. ContraceptionFemalesAdvise individuals of childbearing potential to use reliable method of contraception correctly and consistently, as applicable for the duration of treatment and for days after the last dose of molnupiravir [see Warnings and Precautions (5.1)]. MalesWhile the risk is regarded as low, nonclinical studies to fully assess the potential for molnupiravir to affect offspring of treated males have not been completed. Advise sexually active individuals with partners of childbearing potential to use reliable method of contraception correctly and consistently during treatment and for at least months after the last dose of molnupiravir.The risk beyond three months after the last dose of molnupiravir is unknown. Studies to understand the risk beyond three months are ongoing.Molnupiravir was equivocal (neither clearly positive nor negative) in one in vivo mutagenicity assay of reticulocytes and RBCs which are used to reflect prior effects on hematopoietic stem cells in bone marrow. Molnupiravir was not mutagenic when assessed in second in vivo assay of liver (somatic cells) and bone marrow (somatic cells and stem cells) from transgenic rats administered molnupiravir for 28 days. In contrast to somatic cells, germ cells (eggs and sperm) pass genetic information from generation to generation. planned study of male testicular germ cells from transgenic rats will assess the potential for molnupiravir to affect offspring of treated males [see Nonclinical Toxicology (13.1)]. 8.4 Pediatric Use. Molnupiravir is not authorized for use in patients less than 18 years of age. Bone and cartilage toxicity were observed in 3-month, repeat-dose toxicology study in rats. The safety and efficacy of molnupiravir have not been established in pediatric patients [see Warnings and Precautions (5.3) and Nonclinical Toxicology (13.2)].. 8.5 Geriatric Use. In MOVe-OUT, there was no difference in safety and tolerability between patients >=65 years of age and younger patients who were treated with molnupiravir. No dosage adjustment is recommended based on age. The PK of NHC was similar in geriatric patients compared to younger patients [see Clinical Pharmacology (12.3)].. 8.6 Renal Impairment. No dosage adjustment in patients with any degree of renal impairment is recommended. Renal clearance is not meaningful route of elimination for NHC. Mild or moderate renal impairment did not have meaningful impact on the PK of NHC. While the PK of NHC has not been evaluated in patients with eGFR less than 30 mL/min/1.73m2 or on dialysis, severe renal impairment, and end-stage renal disease (ESRD) are not expected to have significant effect on NHC exposure [see Clinical Pharmacology (12.3)].. 8.7 Hepatic Impairment. No dosage adjustment in patients with hepatic impairment is recommended. Preclinical data indicate that hepatic elimination is not expected to be major route of NHC elimination therefore, hepatic impairment is unlikely to affect NHC exposure [see Clinical Pharmacology (12.3)].

ADVERSE REACTIONS SECTION.

6 ADVERSE REACTIONS. 6.1 Adverse Reactions from Clinical Studies. The following adverse reactions have been observed in the clinical study of molnupiravir that supported the EUA. The adverse reaction rates observed in these clinical trials cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice. Additional adverse events associated with molnupiravir may become apparent with more widespread use.Overall, more than 900 subjects have been exposed to molnupiravir 800 mg twice daily in clinical trials. The safety assessment of molnupiravir is primarily based on an analysis from subjects followed through Day 29 in the Phase study in non-hospitalized subjects with COVID-19 (MOVe-OUT) [see Clinical Studies (14)].The safety of molnupiravir was evaluated based on an analysis of Phase double-blind trial (MOVe-OUT) in which 1,411 non-hospitalized subjects with COVID-19 were randomized and treated with molnupiravir (N=710) or placebo (N=701) for up to days. Adverse events were those reported while subjects were on study intervention or within 14 days of study intervention completion/discontinuation.Discontinuation of study intervention due to an adverse event occurred in 1% of subjects receiving molnupiravir and 3% of subjects receiving placebo. Serious adverse events occurred in 7% of subjects receiving molnupiravir and 10% receiving placebo; most serious adverse events were COVID-19 related. Adverse events leading to death occurred in (<1%) subjects receiving molnupiravir and 12 (2%) of subjects receiving placebo.The most common adverse reactions in the molnupiravir treatment group in MOVe-OUT are presented in Table 1, all of which were Grade (mild) or Grade (moderate).Table 1: Adverse Reactions Occurring in Greater Than or Equal to 1% of Subjects Receiving Molnupiravir in MOVe-OUTFrequencies of adverse reactions are based on all adverse events attributed to study intervention by the investigator. Molnupiravir N=710Placebo N=701Diarrhea2%2%Nausea1%1%Dizziness1%1%Laboratory AbnormalitiesSelected Grade and laboratory abnormalities in chemistry (alanine aminotransferase, aspartate aminotransferase, creatinine, and lipase) and hematology (hemoglobin, platelets, and leukocytes) parameters all occurred at rate of less than or equal to 2% and occurred at similar rate across arms in MOVe-OUT.. 6.2 Post-Authorization Experience. The following adverse reactions have been identified during post-authorization use of molnupiravir. Because these reactions are reported voluntarily from population of uncertain size, it is not always possible to reliably estimate their frequency or establish causal relationship to drug exposure.Immune System Disordershypersensitivity, anaphylaxis, angioedema [see Warnings and Precautions (5.2)] Skin and Subcutaneous Tissue Disorderserythema, rash, urticaria. 6.4 Required Reporting for Serious Adverse Events and Medication Errors. The prescribing healthcare provider and/or the providers designee is/are responsible for mandatory reporting of all serious adverse events and medication errors potentially related to molnupiravir within calendar days from the healthcare providers awareness of the event, using FDA Form 3500 (for information on how to access this form, see below). The FDA requires that such reports, using FDA Form 3500, include the following:Patient demographics and baseline characteristics (e.g., patient identifier, age or date of birth, gender, weight, ethnicity, and race)A statement Molnupiravir use for COVID-19 under Emergency Use Authorization (EUA) under the Describe Event, Problem, or Product Use/Medication Error headingInformation about the serious adverse event or medication error (e.g., signs and symptoms, test/laboratory data, complications, timing of drug initiation in relation to the occurrence of the event, duration of the event, treatments required to mitigate the event, evidence of event improvement/disappearance after stopping or reducing the dosage, evidence of event reappearance after reintroduction, clinical outcomes).Patients preexisting medical conditions and use of concomitant products Information about the product (e.g., dosage, route of administration, NDC ).Submit adverse event and medication error reports, using Form 3500, to FDA MedWatch using one of the following methods:Complete and submit the report online: www.fda.gov/medwatch/report.htm Complete and submit postage-paid FDA Form 3500 (https://www.fda.gov/media/76299/download) and return by: Mail to MedWatch, 5600 Fishers Lane, Rockville, MD 20852-9787, or Fax to 1-800-FDA-0178, or Call 1-800-FDA-1088 to request reporting form In addition, please provide copy of all FDA MedWatch forms to:Merck Sharp Dohme Corp., subsidiary of Merck Co., Inc., Kenilworth, NJ USAFax: 215-616-5677E-mail: dpoc.usamsd.com The prescribing healthcare provider and/or the providers designee is/are responsible for mandatory responses to requests from FDA for information about adverse events and medication errors following receipt of molnupiravir.Serious adverse events are defined as:Death;A life-threatening adverse event;Inpatient hospitalization or prolongation of existing hospitalization;A persistent or significant incapacity or substantial disruption of the ability to conduct normal life functions;A congenital anomaly/birth defect;Other important medical event, which may require medical or surgical intervention to prevent death, life-threatening event, hospitalization, disability, or congenital anomaly.. Patient demographics and baseline characteristics (e.g., patient identifier, age or date of birth, gender, weight, ethnicity, and race). statement Molnupiravir use for COVID-19 under Emergency Use Authorization (EUA) under the Describe Event, Problem, or Product Use/Medication Error heading. Information about the serious adverse event or medication error (e.g., signs and symptoms, test/laboratory data, complications, timing of drug initiation in relation to the occurrence of the event, duration of the event, treatments required to mitigate the event, evidence of event improvement/disappearance after stopping or reducing the dosage, evidence of event reappearance after reintroduction, clinical outcomes).. Patients preexisting medical conditions and use of concomitant products Information about the product (e.g., dosage, route of administration, NDC ).. Complete and submit the report online: www.fda.gov/medwatch/report.htm Complete and submit postage-paid FDA Form 3500 (https://www.fda.gov/media/76299/download) and return by: Mail to MedWatch, 5600 Fishers Lane, Rockville, MD 20852-9787, or Fax to 1-800-FDA-0178, or Mail to MedWatch, 5600 Fishers Lane, Rockville, MD 20852-9787, or Fax to 1-800-FDA-0178, or Call 1-800-FDA-1088 to request reporting form Death;. life-threatening adverse event;. Inpatient hospitalization or prolongation of existing hospitalization;. persistent or significant incapacity or substantial disruption of the ability to conduct normal life functions;. congenital anomaly/birth defect;. Other important medical event, which may require medical or surgical intervention to prevent death, life-threatening event, hospitalization, disability, or congenital anomaly.. 6.5 Other Reporting Requirements. Healthcare facilities and providers will report therapeutics information and utilization data as directed by the U.S. Department of Health and Human Services.

BOXED WARNING SECTION.

MANDATORY REQUIREMENTS FOR ADMINISTRATION OF MOLNUPIRAVIR UNDER EMERGENCY USE AUTHORIZATIONIn order to mitigate the risks of using this unapproved product under the EUA and to optimize the potential benefit of molnupiravir, the following steps are required. Use of molnupiravir under this EUA is limited to the following (all requirements must be met):Treatment of mild-to-moderate COVID-19 in adults with positive result of direct severe acute respiratory syndrome coronavirus (SARS-CoV-2) viral testing, who are at high risk for progression to severe COVID-19, including hospitalization or death and for whom alternative COVID-19 treatment options approved or authorized by FDA are not accessible or clinically appropriate [see Limitations of Authorized Use (1)]. As the prescribing healthcare provider, review the information contained within the Fact Sheet for Patients and Caregivers with your patient or caregiver prior to the patient receiving molnupiravir. Healthcare providers must provide the patient/caregiver with an electronic or hard copy of the Fact Sheet for Patients and Caregivers prior to the patient receiving molnupiravir and must document that the patient/caregiver has been given an electronic or hard copy of the Fact Sheet for Patients and Caregivers.The prescribing healthcare providers must inform the patient/caregiver that: Molnupiravir is an unapproved drug that is authorized for use under this Emergency Use Authorization.Other therapeutics are currently approved or authorized for the same use as molnupiravir. [see Emergency Use Authorization (1) Information Regarding Available Alternatives for the EUA Authorized Use]. There are benefits and risks of taking molnupiravir as outlined in the Fact Sheet for Patients and Caregivers. Merck Sharp Dohme has established pregnancy surveillance program.Females of childbearing potential should use reliable method of contraception correctly and consistently, as applicable, for the duration of treatment and for days after the last dose of molnupiravir. Males of reproductive potential who are sexually active with females of childbearing potential should use reliable method of contraception correctly and consistently during treatment and for at least months after the last dose. The prescribing healthcare provider must assess whether female of childbearing potential is pregnant or not, if clinically indicated [see Warnings and Precautions (5.1) and Use in Specific Populations (8.3)]. Based on findings from animal reproduction studies, molnupiravir may cause fetal harm when administered to pregnant individuals. If molnupiravir is used during pregnancy, prescribing healthcare providers must communicate to the patient the known and potential benefits and the potential risks of molnupiravir use during pregnancy, as outlined in the Fact Sheet for Patients and Caregivers [see Warnings and Precautions (5.1, 5.3), Use in Specific Populations (8.1, 8.3) and Nonclinical Toxicology (13.1)]. If the decision is made to use molnupiravir during pregnancy, the prescriber must document that the known and potential benefits and the potential risks of molnupiravir use during pregnancy, as outlined in the Fact Sheet for Patients and Caregivers, were discussed with the patient.The prescribing healthcare provider must document that pregnant individual was made aware of Merck Sharp Dohmes pregnancy surveillance program at 1-877-888-4231 or pregnancyreporting.msd.com. If the pregnant individual agrees to participate in the pregnancy surveillance program and allows the prescribing healthcare provider to disclose patient specific information to Merck Sharp Dohme, the prescribing healthcare provider must provide the patients name and contact information to Merck Sharp Dohme. The prescribing healthcare provider and/or the providers designee is/are responsible for mandatory reporting of all medication errors and serious adverse events potentially related to molnupiravir within calendar days from the healthcare providers awareness of the event [see Adverse Reactions (6.4)]. For information on clinical studies of molnupiravir and other therapies for the treatment of COVID-19, see www.clinicaltrials.gov.. Treatment of mild-to-moderate COVID-19 in adults with positive result of direct severe acute respiratory syndrome coronavirus (SARS-CoV-2) viral testing, who are at high risk for progression to severe COVID-19, including hospitalization or death and for whom alternative COVID-19 treatment options approved or authorized by FDA are not accessible or clinically appropriate [see Limitations of Authorized Use (1)]. As the prescribing healthcare provider, review the information contained within the Fact Sheet for Patients and Caregivers with your patient or caregiver prior to the patient receiving molnupiravir. Healthcare providers must provide the patient/caregiver with an electronic or hard copy of the Fact Sheet for Patients and Caregivers prior to the patient receiving molnupiravir and must document that the patient/caregiver has been given an electronic or hard copy of the Fact Sheet for Patients and Caregivers.. The prescribing healthcare providers must inform the patient/caregiver that: Molnupiravir is an unapproved drug that is authorized for use under this Emergency Use Authorization.Other therapeutics are currently approved or authorized for the same use as molnupiravir. [see Emergency Use Authorization (1) Information Regarding Available Alternatives for the EUA Authorized Use]. There are benefits and risks of taking molnupiravir as outlined in the Fact Sheet for Patients and Caregivers. Merck Sharp Dohme has established pregnancy surveillance program.Females of childbearing potential should use reliable method of contraception correctly and consistently, as applicable, for the duration of treatment and for days after the last dose of molnupiravir. Males of reproductive potential who are sexually active with females of childbearing potential should use reliable method of contraception correctly and consistently during treatment and for at least months after the last dose. Molnupiravir is an unapproved drug that is authorized for use under this Emergency Use Authorization.. Other therapeutics are currently approved or authorized for the same use as molnupiravir. [see Emergency Use Authorization (1) Information Regarding Available Alternatives for the EUA Authorized Use]. There are benefits and risks of taking molnupiravir as outlined in the Fact Sheet for Patients and Caregivers. Merck Sharp Dohme has established pregnancy surveillance program.. Females of childbearing potential should use reliable method of contraception correctly and consistently, as applicable, for the duration of treatment and for days after the last dose of molnupiravir. Males of reproductive potential who are sexually active with females of childbearing potential should use reliable method of contraception correctly and consistently during treatment and for at least months after the last dose.. The prescribing healthcare provider must assess whether female of childbearing potential is pregnant or not, if clinically indicated [see Warnings and Precautions (5.1) and Use in Specific Populations (8.3)]. Based on findings from animal reproduction studies, molnupiravir may cause fetal harm when administered to pregnant individuals. If molnupiravir is used during pregnancy, prescribing healthcare providers must communicate to the patient the known and potential benefits and the potential risks of molnupiravir use during pregnancy, as outlined in the Fact Sheet for Patients and Caregivers [see Warnings and Precautions (5.1, 5.3), Use in Specific Populations (8.1, 8.3) and Nonclinical Toxicology (13.1)]. If the decision is made to use molnupiravir during pregnancy, the prescriber must document that the known and potential benefits and the potential risks of molnupiravir use during pregnancy, as outlined in the Fact Sheet for Patients and Caregivers, were discussed with the patient.. The prescribing healthcare provider must document that pregnant individual was made aware of Merck Sharp Dohmes pregnancy surveillance program at 1-877-888-4231 or pregnancyreporting.msd.com. If the pregnant individual agrees to participate in the pregnancy surveillance program and allows the prescribing healthcare provider to disclose patient specific information to Merck Sharp Dohme, the prescribing healthcare provider must provide the patients name and contact information to Merck Sharp Dohme. If the pregnant individual agrees to participate in the pregnancy surveillance program and allows the prescribing healthcare provider to disclose patient specific information to Merck Sharp Dohme, the prescribing healthcare provider must provide the patients name and contact information to Merck Sharp Dohme.. The prescribing healthcare provider and/or the providers designee is/are responsible for mandatory reporting of all medication errors and serious adverse events potentially related to molnupiravir within calendar days from the healthcare providers awareness of the event [see Adverse Reactions (6.4)].

CLINICAL PHARMACOLOGY SECTION.

12 CLINICAL PHARMACOLOGY. 12.1 Mechanism of Action. Molnupiravir is prodrug with antiviral activity against SARS-CoV-2. It is metabolized to the cytidine nucleoside analogue, NHC which distributes into cells where NHC is phosphorylated to form the pharmacologically active ribonucleoside triphosphate (NHC-TP). NHC-TP incorporation (as NHC-monophosphate [NHC-MP]) into SARS-CoV-2 RNA by the viral RNA polymerase (nsp12) results in an accumulation of errors in the viral genome leading to inhibition of replication. The mechanism of action (known as viral error catastrophe or viral lethal mutagenesis) is supported by biochemical and cell culture data, studies of SARS-CoV-2 infection in animal models, and analyses of SARS-CoV-2 genome sequences in human subjects treated with molnupiravir.. 12.2 Pharmacodynamics The relationship between NHC and intracellular NHC-TP with antiviral efficacy has not been evaluated clinically. 12.3 Pharmacokinetics. Molnupiravir is 5-isobutyrate prodrug of NHC that is hydrolyzed during or after absorption. NHC, the primary circulating analyte, is taken up by cells and anabolized to NHC-TP. NHC is eliminated by metabolism to uridine and/or cytidine through the same pathways involved in endogenous pyrimidine metabolism. NHC pharmacokinetics are shown in Table 2.Table 2: Pharmacokinetics of NHC After Multiple Oral Administration of 800 mg Molnupiravir Every 12 HoursNHC Geometric Mean (%CV)Values were obtained from Phase study of healthy subjects, unless otherwise indicated.Pharmacokinetics in PatientsAUC0-12hr (nghr/mL)Values were obtained from population PK analysis. 8260 (41.0)Cmax (ng/mL) 2330 (36.9)C12hr (ng/mL) 31.1 (124)Pharmacokinetics in Healthy SubjectsAUC0-12hr (nghr/mL)8330 (17.9)Cmax (ng/mL)2970 (16.8)C12hr (ng/mL)16.7 (42.8)AUC Accumulation Ratio1.09 (11.8)AbsorptionTmax (hr)Median [min max] 1.50 [1.00 2.02]Effect of Food35% reduction in Cmax, no effect on AUCDistributionPlasma Protein Binding (in vitro)0%Apparent Volume of Distribution (L) 142EliminationEffective t1/2 (hr)3.3Apparent Clearance (L/hr) 76.9Fraction of dose excreted in urine over the time interval of 0-12 hours3% (81.6%)Specific PopulationsPopulation PK analysis results indicated that age, sex, race, ethnicity, or disease severity do not meaningfully influence the PK of NHC.Pediatric PatientsMolnupiravir has not been studied in pediatric patients.Patients with Renal ImpairmentRenal clearance is not meaningful route of elimination for NHC. In population PK analysis, mild or moderate renal impairment did not have meaningful impact on the PK of NHC. The PK of molnupiravir and NHC has not been evaluated in patients with eGFR less than 30 mL/min/1.73m2 or on dialysis.Patients with Hepatic ImpairmentThe PK of molnupiravir and NHC has not been evaluated in patients with moderate and severe hepatic impairment. Preclinical data indicate that hepatic elimination is not expected to be major route of NHC elimination; therefore, hepatic impairment is unlikely to affect NHC exposure.Drug Interaction StudiesIn vitro study results indicated that molnupiravir and NHC are not substrates of CYP enzymes or human P-gp and BCRP transporters. In vitro study results also indicated that molnupiravir and NHC are not inhibitors of CYP1A2, 2B6, 2C8, 2C9, 2C19, 2D6, and 3A4 or inhibitors of OATP1B1, OATP1B3, OCT1, OCT2, OAT1, OAT3, MATE1, MATE2K, MRP2, MDR1 and BCRP or inducers of CYP1A2, 2B6, and 3A4. The interaction between molnupiravir with concomitant medications, including other treatments for mild-to-moderate COVID-19, has not been evaluated.. 12.4 Microbiology. Antiviral ActivityNHC, the nucleoside analogue metabolite of molnupiravir, was active in cell culture assays against SARS-CoV-2 with 50% effective concentrations (EC50 values) ranging between 0.67 to 2.66 uM in A-549 cells and 0.32 to 2.03 uM in Vero E6 cells. NHC had similar activity against SARS-CoV-2 variants Alpha (B.1.1.7), Beta (B.1.351), Gamma (P.1), and Delta (B.1.617.2) with EC50 values of 1.59, 1.77 and 1.32 and 1.68 uM, respectively. NHC had non-antagonistic antiviral activity with remdesivir against SARS-CoV-2 in cell culture.ResistanceNo amino acid substitutions in SARS-CoV-2 associated with resistance to NHC have been identified in Phase clinical trials evaluating molnupiravir for the treatment of COVID-19. Studies to evaluate selection of resistance to NHC with SARS-CoV-2 in cell culture have not been completed. Resistance selection studies have been conducted with other coronaviruses (MHV and MERS-CoV) and showed low likelihood of resistance development to NHC. Following 30 passages in cell culture, only 2-fold decrease in susceptibility was observed and no NHC resistance-associated amino acid substitutions were identified. NHC retained activity in cell culture against virus with polymerase (nsp 12) substitutions (e.g., F480L, V557L and E802D) associated with decreased remdesivir sensitivity, indicating lack of cross-resistance.In clinical trials, encoded amino acid changes (substitutions, deletions or insertions) were more likely to be detected in viral sequences in subjects treated with molnupiravir compared to placebo. In small number of subjects amino acid changes in the spike protein occurred at positions targeted by monoclonal antibodies and vaccines. The clinical and public health significance of these changes are unknown.Activity against SARS-CoV-2 in animal modelsThe antiviral activity of molnupiravir has been demonstrated in mouse, hamster, and ferret models of SARS-CoV-2 infection when dosing was administered prior to or within 1-2 days after viral challenge. In SARS-CoV-2 infected ferrets, molnupiravir significantly reduced SARS-CoV-2 viral titers in the upper respiratory tract and completely inhibited viral spread to untreated contact animals. In SARS-CoV-2 infected Syrian hamsters, molnupiravir reduced viral RNA and infectious virus titers in the lungs of animals. Histopathological analysis of lung tissue harvested after infection showed significantly reduced SARS-CoV-2 viral antigen levels and lower abundance of pulmonary lesions in molnupiravir-treated animals compared with controls.In Vitro Cytotoxicity NHC, the nucleoside analogue metabolite of molnupiravir, had variable cytotoxicity against different mammalian cell types with CC50 values ranging from 7.5 uM (human lymphoid CEM cell line) to >100 uM, in 3-day exposure assays. Molnupiravir inhibited the proliferation of human bone marrow progenitor cells with CC50 values of 24.9 uM and 7.7 uM for erythroid and myeloid progenitor proliferation, respectively, in 14-day colony formation assays.

CLINICAL STUDIES SECTION.

14 CLINICAL STUDIES. Clinical data supporting this EUA are based on data from 1,433 randomized subjects in the Phase MOVe-OUT trial (NCT04575597). MOVe-OUT is randomized, placebo-controlled, double-blind clinical trial studying molnupiravir for the treatment of non-hospitalized patients with mild-to-moderate COVID-19 who are at risk for progressing to severe COVID-19 and/or hospitalization. Eligible subjects were 18 years of age and older and had one or more pre-defined risk factors for disease progression: over 60 years of age, diabetes, obesity (BMI >=30), chronic kidney disease, serious heart conditions, chronic obstructive pulmonary disease, or active cancer. The study included symptomatic subjects not vaccinated against SARS-CoV-2 and who had laboratory confirmed SARS-CoV-2 infection and symptom onset within days of randomization. Subjects were randomized 1:1 to receive 800 mg of molnupiravir or placebo orally twice daily for days.At baseline, in all randomized subjects, the median age was 43 years (range:18 to 90); 17% of subjects were over 60 years of age and 3% were 75 years of age or older; 49% of subjects were male; 57% were White, 5% Black or African American, 3% Asian, 50% Hispanic or Latino. The majority of subjects were enrolled from sites in Latin America (46%) and Europe (33%); 12% were enrolled in Africa, 6% were enrolled in North America and 3% were enrolled in Asia. Forty-eight percent of subjects received molnupiravir or placebo within days of COVID-19 symptom onset. The most common risk factors were obesity (74%), over 60 years of age (17%), and diabetes (16%). Among 792 subjects (55% of total randomized population) with available baseline SARS-CoV-2 variant/clade identification results, 58% were infected with Delta (B.1.617.2 and AY lineages), 20% were infected with Mu (B.1.621), 11% were infected with Gamma (P.1), and the remainder were infected with other variants/clades. Overall, baseline demographic and disease characteristics were well balanced between the treatment arms.Table provides the results of the primary endpoint (the percentage of subjects who were hospitalized or died through Day 29 due to any cause). The efficacy results are based on unvaccinated adults who were 18 years of age and older and had one or more pre-defined risk factors for disease progression: over 60 years of age, diabetes, obesity (BMI >=30), chronic kidney disease, serious heart conditions, chronic obstructive pulmonary disease, or active cancer. Please refer to Figure for results by certain subgroups. These subgroup analyses are considered exploratory. Data are not available in certain subgroups of subjects who are at high risk for progression to severe COVID-19 as defined by CDC. Table 3. Efficacy Results in Non-Hospitalized Adults with COVID-19The determination of primary efficacy was based on planned interim analysis of 762 subjects. At the interim analysis, 7.3% of patients who received molnupiravir were either hospitalized or died through Day 29 (28/385), compared with 14.1% of placebo-treated patients (53/377). The adjusted risk difference was -6.8% with 95% CI of (-11.3%, -2.4%) and 2-sided p-value 0.0024. Molnupiravir(N=709) (%)Placebo(N=699) (%)Adjusted Risk Difference% (95% CI)Adjusted relative risk reduction of molnupiravir compared to placebo for all randomized subjects was 30% (95% CI: 1%, 51%).Analyses are adjusted by the stratification factor of time of COVID-19 symptom onset (<=3 days vs. >3 [4-5] days).All-cause hospitalization >=24 hours for acute care or death through Day 2948 (6.8%)68 (9.7%)-3.0% (-5.9%, -0.1%)All-cause mortality through Day 291 (0.1%)9 (1.3%)Figure 1. Subgroup Efficacy Results in Non-Hospitalized Adults with COVID-19 All-Randomized SubjectsThe corresponding confidence interval is based on Miettinen Nurminen method.The modified intent-to-treat population is the efficacy analysis population.Baseline serum samples were evaluated with the Roche Elecsys anti-N assay to test for the presence of antibodies (IgM, IgG and IgA) against the SARS-CoV-2 nucleocapsid protein.The findings of these subgroup analyses are considered exploratory.. Figure 1.

FEMALES & MALES OF REPRODUCTIVE POTENTIAL SECTION.

8.3 Females and Males of Reproductive Potential. Based on animal studies, molnupiravir may cause fetal harm when administered to pregnant individual.Pregnancy TestingPrior to initiating treatment with molnupiravir, assess whether an individual of childbearing potential is pregnant or not, if clinically indicated [see Warnings and Precautions (5.1)]. ContraceptionFemalesAdvise individuals of childbearing potential to use reliable method of contraception correctly and consistently, as applicable for the duration of treatment and for days after the last dose of molnupiravir [see Warnings and Precautions (5.1)]. MalesWhile the risk is regarded as low, nonclinical studies to fully assess the potential for molnupiravir to affect offspring of treated males have not been completed. Advise sexually active individuals with partners of childbearing potential to use reliable method of contraception correctly and consistently during treatment and for at least months after the last dose of molnupiravir.The risk beyond three months after the last dose of molnupiravir is unknown. Studies to understand the risk beyond three months are ongoing.Molnupiravir was equivocal (neither clearly positive nor negative) in one in vivo mutagenicity assay of reticulocytes and RBCs which are used to reflect prior effects on hematopoietic stem cells in bone marrow. Molnupiravir was not mutagenic when assessed in second in vivo assay of liver (somatic cells) and bone marrow (somatic cells and stem cells) from transgenic rats administered molnupiravir for 28 days. In contrast to somatic cells, germ cells (eggs and sperm) pass genetic information from generation to generation. planned study of male testicular germ cells from transgenic rats will assess the potential for molnupiravir to affect offspring of treated males [see Nonclinical Toxicology (13.1)].

MICROBIOLOGY SECTION.

12.4 Microbiology. Antiviral ActivityNHC, the nucleoside analogue metabolite of molnupiravir, was active in cell culture assays against SARS-CoV-2 with 50% effective concentrations (EC50 values) ranging between 0.67 to 2.66 uM in A-549 cells and 0.32 to 2.03 uM in Vero E6 cells. NHC had similar activity against SARS-CoV-2 variants Alpha (B.1.1.7), Beta (B.1.351), Gamma (P.1), and Delta (B.1.617.2) with EC50 values of 1.59, 1.77 and 1.32 and 1.68 uM, respectively. NHC had non-antagonistic antiviral activity with remdesivir against SARS-CoV-2 in cell culture.ResistanceNo amino acid substitutions in SARS-CoV-2 associated with resistance to NHC have been identified in Phase clinical trials evaluating molnupiravir for the treatment of COVID-19. Studies to evaluate selection of resistance to NHC with SARS-CoV-2 in cell culture have not been completed. Resistance selection studies have been conducted with other coronaviruses (MHV and MERS-CoV) and showed low likelihood of resistance development to NHC. Following 30 passages in cell culture, only 2-fold decrease in susceptibility was observed and no NHC resistance-associated amino acid substitutions were identified. NHC retained activity in cell culture against virus with polymerase (nsp 12) substitutions (e.g., F480L, V557L and E802D) associated with decreased remdesivir sensitivity, indicating lack of cross-resistance.In clinical trials, encoded amino acid changes (substitutions, deletions or insertions) were more likely to be detected in viral sequences in subjects treated with molnupiravir compared to placebo. In small number of subjects amino acid changes in the spike protein occurred at positions targeted by monoclonal antibodies and vaccines. The clinical and public health significance of these changes are unknown.Activity against SARS-CoV-2 in animal modelsThe antiviral activity of molnupiravir has been demonstrated in mouse, hamster, and ferret models of SARS-CoV-2 infection when dosing was administered prior to or within 1-2 days after viral challenge. In SARS-CoV-2 infected ferrets, molnupiravir significantly reduced SARS-CoV-2 viral titers in the upper respiratory tract and completely inhibited viral spread to untreated contact animals. In SARS-CoV-2 infected Syrian hamsters, molnupiravir reduced viral RNA and infectious virus titers in the lungs of animals. Histopathological analysis of lung tissue harvested after infection showed significantly reduced SARS-CoV-2 viral antigen levels and lower abundance of pulmonary lesions in molnupiravir-treated animals compared with controls.In Vitro Cytotoxicity NHC, the nucleoside analogue metabolite of molnupiravir, had variable cytotoxicity against different mammalian cell types with CC50 values ranging from 7.5 uM (human lymphoid CEM cell line) to >100 uM, in 3-day exposure assays. Molnupiravir inhibited the proliferation of human bone marrow progenitor cells with CC50 values of 24.9 uM and 7.7 uM for erythroid and myeloid progenitor proliferation, respectively, in 14-day colony formation assays.

NONCLINICAL TOXICOLOGY SECTION.

13 NONCLINICAL TOXICOLOGY. 13.1 Carcinogenesis, Mutagenesis, Impairment of Fertility. CarcinogenesisA mouse carcinogenicity study with molnupiravir is ongoing.MutagenesisMolnupiravir and NHC were positive in the in vitro bacterial reverse mutation assay (Ames assay) with and without metabolic activation. Molnupiravir was studied in two in vivo rodent mutagenicity models. The in vivo Pig-a mutagenicity assay gave equivocal results. Molnupiravir was negative in the in vivo Big Blue(R) (cII Locus) transgenic rodent mutagenicity assay. Molnupiravir was negative for induction of chromosomal damage in in vitro micronucleus (with and without metabolic activation) and in vivo rat micronucleus assays. To assess effects on germ cells, transgenic rodent male germ cell mutagenicity assay is planned.Based on the totality of the available genotoxicity data and the duration of treatment (5 days), molnupiravir is low risk for genotoxicity.Impairment of FertilityThere were no effects on fertility, mating performance or early embryonic development when molnupiravir was administered to female or male rats at NHC exposures approximately and times, respectively, the human NHC exposure at the RHD.. 13.2 Animal Toxicology and/or Pharmacology. Bone and cartilage toxicity changes resulting in impaired transformation of growth cartilage into new bone were observed in the femur and tibia of rats in 3-month toxicity study at >= 500 mg/kg/day (5 times the human NHC exposure at the RHD). There was no bone or cartilage toxicity in 1-month toxicity study in rats up to 500 mg/kg/day (4 and times the human NHC exposure at the RHD in females and males, respectively), in dogs dosed for 14 days up to 50 mg/kg/day (similar to the human NHC exposure at the RHD), or in 1-month toxicity study in mice up to 2,000 mg/kg/day (19 times the human NHC exposure at the RHD). Growth cartilage is not present in mature skeletons, therefore the bone and cartilage findings are not relevant for adult humans but may be relevant for pediatric patients [see Warnings and Precautions (5.3) and Use in Specific Populations (8.4)].Reversible, dose-related bone marrow toxicity affecting all hematopoietic cell lines was observed in dogs at >=17 mg/kg/day (less than the human NHC exposure at the RHD). Mild decreases in peripheral blood cell and platelet counts were seen after days of molnupiravir treatment progressing to more severe hematological changes after 14 days of treatment. Neither bone marrow nor hematological toxicity was observed in 1-month toxicity study in mice up to 2,000 mg/kg/day (19 times the human NHC exposure at the RHD) and 3-month toxicity study in rats up to 1,000 mg/kg/day (9 and 15 times the human NHC exposure at the RHD in females and males, respectively).

PATIENT COUNSELING INFORMATION.

17 PATIENT COUNSELING INFORMATION. As prescribing healthcare practitioner, you must communicate to the patient and/or caregiver information consistent with the FACT SHEET FOR PATIENTS AND CAREGIVERS and document that information was provided. copy of this Fact Sheet should be provided to the patient and/or caregiver prior to receiving molnupiravir [see Box].Hypersensitivity ReactionsInform patients that hypersensitivity reactions have been reported, even following single dose of molnupiravir, and to discontinue the drug and to inform their healthcare provider at the first sign of skin rash, hives or other skin reactions, rapid heartbeat, difficulty in swallowing or breathing, any swelling suggesting angioedema (for example, swelling of the lips, tongue, face, tightness of the throat, hoarseness), or other symptoms of an allergic reaction [see Warnings and Precautions (5.2)].Risk of Fetal ToxicityAdvise patients that molnupiravir is not recommended for use in pregnancy because it may cause fetal harm. Advise individuals of childbearing potential to inform their healthcare provider of known or suspected pregnancy [see Box, Warnings and Precautions (5.1) and Use in Specific Populations (8.1)]. Advise individuals of childbearing potential to use effective contraception correctly and consistently while taking molnupiravir and for days after the last dose. While the risk is regarded as low, nonclinical studies to fully assess the potential for molnupiravir to affect offspring of treated males have not been completed. Advise sexually active individuals with partners of childbearing potential to use reliable method of contraception consistently and correctly while taking molnupiravir and for at least months after the last dose of molnupiravir. The risk beyond months after the last dose of molnupiravir is unknown. Studies to understand the risk beyond three months are ongoing [see Use in Specific Populations (8.3)]. Risk of Bone and Cartilage ToxicityMolnupiravir is not authorized for use in patients less than 18 year of age as it may affect bone growth and cartilage formation [see Warnings and Precautions (5.3) and Use in Specific Populations (8.4)]. Pregnancy Surveillance ProgramThere is pregnancy surveillance program that monitors pregnancy outcomes in individuals exposed to molnupiravir during pregnancy. Encourage participation and advise patients about how they may enroll in the pregnancy surveillance program. Advise patients who have taken molnupiravir during pregnancy to report their pregnancy to Merck Sharp Dohme Corp., subsidiary of Merck Co., Inc., Kenilworth, NJ USA at 1-877-888-4231 or pregnancyreporting.msd.com [see Use in Specific Populations (8.1)].LactationBreastfeeding is not recommended while taking molnupiravir and for days after the last dose of molnupiravir. Advise lactating individuals to consider interrupting breastfeeding and to consider pumping and discarding breast milk during treatment and for days after the last dose of molnupiravir [see Use in Specific Populations (8.2)].Administration InstructionsInform patients to take molnupiravir with or without food. Advise patients to swallow molnupiravir capsules whole, and to not open, break, or crush the capsules. Instruct patients that if they miss dose of molnupiravir and it is within 10 hours of the time it is usually taken, the patient should take it as soon as possible and resume the normal dosing schedule. If the patient misses dose by more than 10 hours, the patient should not take the missed dose and instead take the next dose at the regularly scheduled time. Advise the patient to not double the dose to make up for missed dose [see Dosage and Administration (2.2)].Alert the patient of the importance of completing the full 5-day treatment course and to continuing isolation in accordance with public health recommendations to maximize viral clearance and minimize transmission of SARS-CoV-2 [see Dosage and Administration (2.2)].

PHARMACOKINETICS SECTION.

12.3 Pharmacokinetics. Molnupiravir is 5-isobutyrate prodrug of NHC that is hydrolyzed during or after absorption. NHC, the primary circulating analyte, is taken up by cells and anabolized to NHC-TP. NHC is eliminated by metabolism to uridine and/or cytidine through the same pathways involved in endogenous pyrimidine metabolism. NHC pharmacokinetics are shown in Table 2.Table 2: Pharmacokinetics of NHC After Multiple Oral Administration of 800 mg Molnupiravir Every 12 HoursNHC Geometric Mean (%CV)Values were obtained from Phase study of healthy subjects, unless otherwise indicated.Pharmacokinetics in PatientsAUC0-12hr (nghr/mL)Values were obtained from population PK analysis. 8260 (41.0)Cmax (ng/mL) 2330 (36.9)C12hr (ng/mL) 31.1 (124)Pharmacokinetics in Healthy SubjectsAUC0-12hr (nghr/mL)8330 (17.9)Cmax (ng/mL)2970 (16.8)C12hr (ng/mL)16.7 (42.8)AUC Accumulation Ratio1.09 (11.8)AbsorptionTmax (hr)Median [min max] 1.50 [1.00 2.02]Effect of Food35% reduction in Cmax, no effect on AUCDistributionPlasma Protein Binding (in vitro)0%Apparent Volume of Distribution (L) 142EliminationEffective t1/2 (hr)3.3Apparent Clearance (L/hr) 76.9Fraction of dose excreted in urine over the time interval of 0-12 hours3% (81.6%)Specific PopulationsPopulation PK analysis results indicated that age, sex, race, ethnicity, or disease severity do not meaningfully influence the PK of NHC.Pediatric PatientsMolnupiravir has not been studied in pediatric patients.Patients with Renal ImpairmentRenal clearance is not meaningful route of elimination for NHC. In population PK analysis, mild or moderate renal impairment did not have meaningful impact on the PK of NHC. The PK of molnupiravir and NHC has not been evaluated in patients with eGFR less than 30 mL/min/1.73m2 or on dialysis.Patients with Hepatic ImpairmentThe PK of molnupiravir and NHC has not been evaluated in patients with moderate and severe hepatic impairment. Preclinical data indicate that hepatic elimination is not expected to be major route of NHC elimination; therefore, hepatic impairment is unlikely to affect NHC exposure.Drug Interaction StudiesIn vitro study results indicated that molnupiravir and NHC are not substrates of CYP enzymes or human P-gp and BCRP transporters. In vitro study results also indicated that molnupiravir and NHC are not inhibitors of CYP1A2, 2B6, 2C8, 2C9, 2C19, 2D6, and 3A4 or inhibitors of OATP1B1, OATP1B3, OCT1, OCT2, OAT1, OAT3, MATE1, MATE2K, MRP2, MDR1 and BCRP or inducers of CYP1A2, 2B6, and 3A4. The interaction between molnupiravir with concomitant medications, including other treatments for mild-to-moderate COVID-19, has not been evaluated.

PREGNANCY SECTION.

8.1 Pregnancy. Pregnancy Surveillance ProgramThere is pregnancy surveillance program that monitors pregnancy outcomes in individuals exposed to molnupiravir during pregnancy. The prescribing healthcare provider must document that pregnant individual was made aware of Merck Sharp Dohmes pregnancy surveillance program at 1-877-888-4231 or pregnancyreporting.msd.com. If the pregnant individual agrees to participate in the pregnancy surveillance program and allows the prescribing healthcare provider to disclose patient specific information to Merck Sharp Dohme, the prescribing healthcare provider must provide the patients name and contact information to Merck Sharp Dohme. Pregnant individuals exposed to molnupiravir can also report the exposure by contacting Merck Sharp Dohme Corp., subsidiary of Merck Co., Inc., Kenilworth, NJ USA at 1-877-888-4231 or pregnancyreporting.msd.com.Risk SummaryBased on animal data, molnupiravir may cause fetal harm when administered to pregnant individuals. There are no available human data on the use of molnupiravir in pregnant individuals to evaluate the risk of major birth defects, miscarriage or adverse maternal or fetal outcomes; therefore, molnupiravir is not recommended during pregnancy [see Box and Warnings and Precautions (5.1)]. In an animal reproduction study, oral administration of molnupiravir to pregnant rats during the period of organogenesis resulted in embryofetal lethality and teratogenicity at times the human NHC (N4-hydroxycytidine) exposures at the recommended human dose (RHD) and reduced fetal growth at >= times the human NHC exposure at the RHD. Oral administration of molnupiravir to pregnant rabbits during the period of organogenesis resulted in reduced fetal body weights at 18 times the human NHC exposure at the RHD (see Data). When considering molnupiravir for pregnant individual, the prescribing healthcare provider must communicate the known and potential benefits and the potential risks of using molnupiravir during pregnancy to the pregnant individual. Molnupiravir may only be prescribed to pregnant individual after the prescribing healthcare provider has determined that the benefits would outweigh the risks for that individual patient. If the decision is made to use molnupiravir during pregnancy, the prescribing healthcare provider must document that the known and potential benefits and potential risks of using molnupiravir during pregnancy were communicated to the pregnant individual [see Box]. There are maternal and fetal risks associated with untreated COVID-19 in pregnancy (see Clinical Considerations).The estimated background risk of major birth defects and miscarriage for the indicated population is unknown. All pregnancies have background risk of birth defect, loss, or other adverse outcomes. In the U.S. general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is to 4% and 15 to 20%, respectively.Clinical ConsiderationsDisease-associated maternal and/or embryo/fetal riskCOVID-19 in pregnancy is associated with adverse maternal and fetal outcomes, including preeclampsia, eclampsia, preterm birth, premature rupture of membranes, venous thromboembolic disease, and fetal death.DataAnimal DataIn an embryofetal development (EFD) study in rats, molnupiravir was administered orally to pregnant rats at 0, 100, 250, or 500 mg/kg/day from gestation days (GDs) to 17. Molnupiravir was also administered orally to pregnant rats at up to 1,000 mg/kg/day from GDs to 17 in preliminary EFD study. Developmental toxicities included post-implantation losses, malformations of the eye, kidney, and axial skeleton, and rib variations at 1,000 mg/kg/day (8 times the human NHC exposure at the RHD) and decreased fetal body weights and delayed ossification at >=500 mg/kg/day (3 times the human NHC exposure at the RHD). There were no developmental toxicities at <=250 mg/kg/day (less than the human NHC exposure at the RHD). Maternal toxicities included decreased food consumption and body weight losses, resulting in the early sacrifice of two of sixteen animals at 1,000 mg/kg/day, and decreased body weight gain at 500 mg/kg/day. In an EFD study in rabbits, molnupiravir was administered orally to pregnant rabbits at 0, 125, 400, or 750 mg/kg/day from GDs to 19. Developmental toxicity was limited to reduced fetal body weights at 750 mg/kg/day (18 times the human NHC exposures at the RHD). There was no developmental toxicity at <=400 mg/kg/day (7 times the human NHC exposures at the RHD). Maternal toxicities included reduced food consumption and body weight gains, and abnormal fecal output at 750 mg/kg/day.In pre- and post-natal developmental study, molnupiravir was administered orally to female rats at doses up to 500 mg/kg/day (similar to the human NHC exposure at the RHD) from GD6 through lactation day 20. No effects were observed in offspring.

SPL UNCLASSIFIED SECTION.

FACT SHEET FOR HEALTHCARE PROVIDERS: EMERGENCY USE AUTHORIZATION FOR MOLNUPIRAVIRHIGHLIGHTS OF EMERGENCY USE AUTHORIZATION (EUA)These highlights of the EUA do not include all the information needed to use molnupiravir under the EUA. See the FULL FACT SHEET FOR HEALTHCARE PROVIDERS for molnupiravir. MOLNUPIRAVIR capsules, for oral useOriginal EUA Authorized Date: 12/23/2021Revised EUA Authorized Date: 02/2022 MANDATORY REQUIREMENTS FOR ADMINISTRATION OF MOLNUPIRAVIR UNDER EMERGENCY USE AUTHORIZATIONRefer to FULL FACTSHEET for details.--------------RECENT MAJOR CHANGES-----------Mandatory Requirements Box: Revised requirements pertaining to other therapeutics 02/2022Emergency Use Authorization (Section 1): Updates on available alternatives to molnupiravir 02/2022Warnings and Precautions (Sections 5.2 and 17): addition of hypersensitivity including anaphylaxis 02/2022 Adverse Reactions (Section 6.2): addition of post-authorization experience section 02/2022------------EUA FOR MOLNUPIRAVIR-----------The U.S. Food and Drug Administration (FDA) has issued an EUA for the emergency use of the unapproved molnupiravir, nucleoside analogue that inhibits SARS-CoV-2 replication by viral mutagenesis for the treatment of mild-to-moderate coronavirus disease 2019 (COVID-19) in adults with positive results of direct SARS-CoV-2 viral testing who are at high risk for progression to severe COVID-19, including hospitalization or death, and for whom alternative COVID-19 treatment options approved or authorized by FDA are not accessible or clinically appropriate. Molnupiravir is not FDA-approved for any use including for use for the treatment of COVID-19. Prior to initiating treatment with molnupiravir, carefully consider the known and potential risks and benefits. (1)LIMITATIONS OF AUTHORIZED USE (1)Molnupiravir is not authorized -for use in patients less than 18 years of age (5.3)-for initiation of treatment in patients requiring hospitalization due to COVID-19. Benefit of treatment with molnupiravir has not been observed in subjects when treatment was initiated after hospitalization due to COVID-19. (2.1) -for use for longer than consecutive days.-for pre-exposure or post-exposure prophylaxis for prevention of COVID-19. Molnupiravir may only be prescribed for an individual patient by physicians, advanced practice registered nurses, and physician assistants that are licensed or authorized under state law to prescribe drugs in the therapeutic class to which molnupiravir belongs (i.e., anti-infectives).Molnupiravir is authorized only for the duration of the declaration that circumstances exist justifying the authorization of the emergency use of molnupiravir under section 564(b)(1) of the Act, 21 U.S.C. 360bbb-3(b)(1), unless the authorization is terminated or revoked sooner.See the box in the beginning of the Full Fact Sheet for details on mandatory requirements for administration of molnupiravir under emergency use authorization.See Full Fact Sheet for Healthcare Providers for the justification for emergency use of drugs during the COVID-19 pandemic, information on available alternatives, and additional information on COVID-19. ------DOSAGE AND ADMINISTRATION------800 mg (four 200 mg capsules) taken orally every 12 hours for days, with or without food. (2.1)Take molnupiravir as soon as possible after diagnosis of COVID-19 has been made, and within days of symptom onset. (2.1)Completion of the full 5-day treatment course and continued isolation in accordance with public health recommendations are important to maximize viral clearance and minimize transmission of SARS-CoV-2. (2.1)Molnupiravir is not authorized for use for longer than consecutive days because the safety and efficacy have not been established. (2.1)-----DOSAGE FORMS AND STRENGTHS-----Capsules: 200 mg (3)------------CONTRAINDICATIONS------------No contraindications have been identified based on the limited available data on the emergency use of molnupiravir authorized under this EUA. (4)------WARNINGS AND PRECAUTIONS------Embryo-Fetal Toxicity: Molnupiravir is not recommended for use during pregnancy. (5.1, 8.1, 8.3)Hypersensitivity reactions, including anaphylaxis have been reported with molnupiravir. If signs and symptoms of clinically significant hypersensitivity reaction or anaphylaxis occur, immediately discontinue molnupiravir. (5.2)Bone and Cartilage Toxicity: Molnupiravir is not authorized for use in patients less than 18 years of age because it may affect bone and cartilage growth. (5.3, 8.4, 13.2)-----------ADVERSE REACTIONS-----------Most common adverse reactions (incidence >= 1%) are diarrhea, nausea, and dizziness. (6.1) You or your designee must report all SERIOUS ADVERSE EVENTS or MEDICATION ERRORS potentially related to molnupiravir (1) by submitting FDA Form 3500 online, (2) by downloading this form and then submitting by mail or fax, or (3) contacting the FDA at 1-800-FDA-1088 to request this form. Please also provide copy of this form to Merck Sharp Dohme Corp., subsidiary of Merck Co., Inc., Kenilworth, NJ USA at 1-800-672-6372 or Fax 215-616-5677 (6.4)-------------DRUG INTERACTIONS--------------No drug interactions have been identified based on the limited available data on the emergency use of molnupiravir authorized under this EUA. (7)----------USE IN SPECIFIC POPULATIONS---------Pregnancy: The use of molnupiravir is not recommended during pregnancy. Advise individuals of childbearing potential to use effective contraception correctly and consistently, as applicable, for the duration of treatment and for days after the last dose of molnupiravir. (8.1, 8.3)Lactation: Breastfeeding is not recommended during treatment and for days after the last dose of molnupiravir. lactating individual may consider interrupting breastfeeding and may consider pumping and discarding breast milk during treatment and for days after the last dose of molnupiravir. (8.2) See FACT SHEET FOR PATIENTS AND CAREGIVERS.. Molnupiravir is not authorized -for use in patients less than 18 years of age (5.3)-for initiation of treatment in patients requiring hospitalization due to COVID-19. Benefit of treatment with molnupiravir has not been observed in subjects when treatment was initiated after hospitalization due to COVID-19. (2.1) -for use for longer than consecutive days.-for pre-exposure or post-exposure prophylaxis for prevention of COVID-19. -for use in patients less than 18 years of age (5.3). -for initiation of treatment in patients requiring hospitalization due to COVID-19. Benefit of treatment with molnupiravir has not been observed in subjects when treatment was initiated after hospitalization due to COVID-19. (2.1) -for use for longer than consecutive days.. -for pre-exposure or post-exposure prophylaxis for prevention of COVID-19.. 800 mg (four 200 mg capsules) taken orally every 12 hours for days, with or without food. (2.1). Take molnupiravir as soon as possible after diagnosis of COVID-19 has been made, and within days of symptom onset. (2.1). Completion of the full 5-day treatment course and continued isolation in accordance with public health recommendations are important to maximize viral clearance and minimize transmission of SARS-CoV-2. (2.1). Molnupiravir is not authorized for use for longer than consecutive days because the safety and efficacy have not been established. (2.1). Embryo-Fetal Toxicity: Molnupiravir is not recommended for use during pregnancy. (5.1, 8.1, 8.3). Hypersensitivity reactions, including anaphylaxis have been reported with molnupiravir. If signs and symptoms of clinically significant hypersensitivity reaction or anaphylaxis occur, immediately discontinue molnupiravir. (5.2). Bone and Cartilage Toxicity: Molnupiravir is not authorized for use in patients less than 18 years of age because it may affect bone and cartilage growth. (5.3, 8.4, 13.2). Pregnancy: The use of molnupiravir is not recommended during pregnancy. Advise individuals of childbearing potential to use effective contraception correctly and consistently, as applicable, for the duration of treatment and for days after the last dose of molnupiravir. (8.1, 8.3). Lactation: Breastfeeding is not recommended during treatment and for days after the last dose of molnupiravir. lactating individual may consider interrupting breastfeeding and may consider pumping and discarding breast milk during treatment and for days after the last dose of molnupiravir. (8.2).

WARNINGS AND PRECAUTIONS SECTION.

5 WARNINGS AND PRECAUTIONS. There are limited clinical data available for molnupiravir. Serious and unexpected adverse events may occur that have not been previously reported with molnupiravir use.. 5.1 Embryo-Fetal Toxicity. Based on findings from animal reproduction studies, molnupiravir may cause fetal harm when administered to pregnant individuals. There are no available human data on the use of molnupiravir in pregnant individuals to evaluate the risk of major birth defects, miscarriage or adverse maternal or fetal outcomes; therefore, molnupiravir is not recommended for use during pregnancy. When considering molnupiravir for pregnant individual, the prescribing healthcare provider must communicate the known and potential benefits and the potential risks of using molnupiravir during pregnancy to the pregnant individual. Molnupiravir is authorized to be prescribed to pregnant individual only after the healthcare provider has determined that the benefits would outweigh the risks for that individual patient. If the decision is made to use molnupiravir during pregnancy, the prescribing healthcare provider must document that the known and potential benefits and the potential risks of using molnupiravir during pregnancy were communicated to the pregnant individual.Advise individuals of childbearing potential of the potential risk to fetus and to use an effective method of contraception correctly and consistently, as applicable, during treatment with molnupiravir and for days after the final dose [see Use in Specific Populations (8.1, 8.3 and Nonclinical Toxicology (13.1)].Prior to initiating treatment with molnupiravir, assess whether an individual of childbearing potential is pregnant or not, if clinically indicated. Pregnancy status does not need to be confirmed in patients who have undergone permanent sterilization, are currently using an intrauterine system or contraceptive implant, or in whom pregnancy is not possible. In all other patients, assess whether the patient is pregnant based on the first day of last menstrual period in individuals who have regular menstrual cycles, is using reliable method of contraception correctly and consistently or have had negative pregnancy test. pregnancy test is recommended if the individual has irregular menstrual cycles, is unsure of the first day of last menstrual period or is not using effective contraception correctly and consistently [see Box].. 5.2 Hypersensitivity Including Anaphylaxis. Hypersensitivity reactions, including anaphylaxis, have been reported with molnupiravir. If signs and symptoms of clinically significant hypersensitivity reaction or anaphylaxis occur, immediately discontinue molnupiravir and initiate appropriate medications and/or supportive care.. 5.3 Bone and Cartilage Toxicity. Molnupiravir is not authorized for use in patients less than 18 years of age because it may affect bone and cartilage growth. Bone and cartilage toxicity was observed in rats after repeated dosing [see Nonclinical Toxicity (13.2)]. The safety and efficacy of molnupiravir have not been established in pediatric patients [see Use in Specific Populations (8.4)].