PIFELTRO

Warnings and Precautions, Severe Skin Reactions ( 5.1 ) 11/2024

1 INDICATIONS AND USAGE PIFELTRO ® is indicated in combination with other antiretroviral agents for the treatment of HIV-1 infection in adults and pediatric patients weighing at least 35 kg: with no prior antiretroviral treatment history; OR to replace the current antiretroviral regimen in those who are virologically-suppressed (HIV-1 RNA less than 50 copies per mL) on a stable antiretroviral regimen with no history of treatment failure and no known substitutions associated with resistance to doravirine [see Clinical Studies (14) ] . PIFELTRO, a non-nucleoside reverse transcriptase inhibitor (NNRTI), is indicated in combination with other antiretroviral agents for the treatment of HIV-1 infection in adults and pediatric patients weighing at least 35 kg: with no prior antiretroviral treatment history, OR to replace the current antiretroviral regimen in those who are virologically-suppressed (HIV-1 RNA less than 50 copies per mL) on a stable antiretroviral regimen with no history of treatment failure and no known substitutions associated with resistance to doravirine. ( 1 )

2 DOSAGE AND ADMINISTRATION Recommended dosage: One tablet taken orally once daily with or without food in adults and pediatric patients weighing at least 35 kg. ( 2.1 ) Dosage adjustment with rifabutin: One tablet taken twice daily (approximately 12 hours apart). ( 2.2 ) 2.1 Recommended Dosage The recommended dosage regimen of PIFELTRO in adults and pediatric patients weighing at least 35 kg is one 100 mg tablet taken orally once daily with or without food [see Clinical Pharmacology (12.3) ] . 2.2 Dosage Adjustment with Rifabutin If PIFELTRO is co-administered with rifabutin, increase PIFELTRO dosage to one tablet twice daily (approximately 12 hours apart) for the duration of rifabutin co-administration [see Drug Interactions (7.1) and Clinical Pharmacology (12.3) ].

3 DOSAGE FORMS AND STRENGTHS PIFELTRO film-coated tablets are white, oval-shaped tablets, debossed with the corporate logo and 700 on one side and plain on the other side. Each tablet contains 100 mg doravirine. Tablets: 100 mg doravirine. ( 3 )

4 CONTRAINDICATIONS PIFELTRO is contraindicated when co-administered with drugs that are strong cytochrome P450 (CYP)3A enzyme inducers as significant decreases in doravirine plasma concentrations may occur, which may decrease the effectiveness of PIFELTRO [see Warnings and Precautions (5.2) , Drug Interactions (7.1) , and Clinical Pharmacology (12.3) ] . These drugs include, but are not limited to, the following: the anticonvulsants carbamazepine, oxcarbazepine, phenobarbital, phenytoin the androgen receptor inhibitor enzalutamide the antimycobacterials rifampin, rifapentine the cytotoxic agent mitotane St. John's wort ( Hypericum perforatum) PIFELTRO is contraindicated when co-administered with drugs that are strong cytochrome P450 (CYP)3A enzyme inducers as significant decreases in doravirine plasma concentrations may occur, which may decrease the effectiveness of PIFELTRO. ( 4 )

6 ADVERSE REACTIONS The following adverse reactions are discussed in other sections of the labeling: Skin and Hypersensitivity Reactions [see Warnings and Precautions (5.1) ] Immune Reconstitution Syndrome [see Warnings and Precautions (5.3) ] Most common adverse reactions (incidence greater than or equal to 5%, all grades) are nausea, dizziness, headache, fatigue, diarrhea, abdominal pain, and abnormal dreams. ( 6.1 ) To report SUSPECTED ADVERSE REACTIONS, contact Merck Sharp & Dohme LLC at 1-877-888-4231 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch . 6.1 Clinical Trials Experience Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice. Adverse Reactions in Adults with No Antiretroviral Treatment History The safety assessment of PIFELTRO used in combination with other antiretroviral agents is based on Week 96 data from two Phase 3, randomized, international, multicenter, double-blind, active-controlled trials (DRIVE-FORWARD (Protocol 018) and DRIVE-AHEAD (Protocol 021)). In DRIVE-FORWARD, 766 adult participants received either PIFELTRO 100 mg (n=383) or darunavir 800 mg + ritonavir 100 mg (DRV+r) (n=383) once daily, each in combination with emtricitabine/tenofovir disoproxil fumarate (FTC/TDF) or abacavir/lamivudine (ABC/3TC). By Week 96, 2% in the PIFELTRO group and 3% in the DRV+r group had adverse events leading to discontinuation of study medication. In DRIVE-AHEAD, 728 adult participants received either DELSTRIGO [doravirine (DOR)/3TC/TDF] (n=364) or efavirenz (EFV)/FTC/TDF once daily (n=364). By Week 96, 3% in the DELSTRIGO group and 7% in the EFV/FTC/TDF group had adverse events leading to discontinuation of study medication. Adverse reactions reported in greater than or equal to 5% of participants in any treatment group in DRIVE-FORWARD and DRIVE-AHEAD are presented in Table 1. Table 1: Adverse Reactions Frequencies of adverse reactions are based on all adverse events attributed to trial drugs by the investigator. (All Grades) Reported in ≥5% No adverse reactions of Grade 2 or higher (moderate or severe) occurred in ≥ 2% of participants treated with doravirine. of Participants in Any Treatment Group in Adults with No Antiretroviral Treatment History in DRIVE-FORWARD and DRIVE-AHEAD (Week 96) DRIVE-FORWARD DRIVE-AHEAD PIFELTRO+2 NRTIs NRTI = nucleoside reverse transcriptase inhibitor. Once Daily N=383 DRV+r+2 NRTIs Once Daily N=383 DELSTRIGO Once Daily N=364 EFV/FTC/TDF Once Daily N=364 NRTIs = FTC/TDF or ABC/3TC. Fatigue: includes fatigue, asthenia, malaise Abdominal Pain: includes abdominal discomfort, abdominal pain, abdominal pain lower, abdominal pain upper, epigastric discomfort Rash: includes rash, rash erythematous, rash generalized, rash macular, rash maculo-papular, rash papular, rash pruritic, rash pustular Nausea 7% 8% 5% 7% Headache 6% 3% 4% 5% Fatigue 6% 3% 4% 4% Diarrhea 6% 13% 4% 6% Abdominal Pain 5% 2% 1% 2% Dizziness 3% 2% 7% 32% Rash 2% 3% 2% 12% Abnormal Dreams 1% 1.3 - 1.8 × ULN or Increase of >0.3 mg/dL above baseline 4% 6% 3% 2% >1.8 × ULN or Increase of ≥1.5 × above baseline 4% 4% 3% 2% Aspartate aminotransferase (IU/L) 2.5 - 500 mg/dL 1% 2% 1% 3% Change in Lipids from Baseline For DRIVE-FORWARD and DRIVE-AHEAD, changes from baseline at Week 48 in LDL-cholesterol, non-HDL-cholesterol, total cholesterol, triglycerides, and HDL-cholesterol are shown in Table 4. Changes from baseline at Week 96 were similar to those seen at Week 48. The LDL and non-HDL comparisons were pre-specified and are summarized in Table 4. The differences were statistically significant, showing superiority for doravirine for both parameters. The clinical benefit of these findings has not been demonstrated. Table 4: Mean Change from Baseline in Fasting Lipids in Adult Participants with No Antiretroviral Treatment Hist …

7 DRUG INTERACTIONS Consult the full prescribing information prior to and during treatment for important potential drug-drug interactions. ( 4 , 5.2 , 7 ) 7.1 Effect of Other Drugs on PIFELTRO Co-administration of PIFELTRO with a CYP3A inducer decreases doravirine plasma concentrations, which may reduce PIFELTRO efficacy [see Contraindications (4) , Warnings and Precautions (5.2) , and Clinical Pharmacology (12.3) ] . Co-administration of PIFELTRO and drugs that are inhibitors of CYP3A may result in increased plasma concentrations of doravirine. Table 6 shows significant drug interactions with PIFELTRO. Table 6: Drug Interactions with PIFELTRO This table is not all inclusive. Concomitant Drug Class: Drug Name Effect on Concentration Clinical Comment ↑ = increase, ↓ = decrease All other drug-drug interactions shown are anticipated based on the known metabolic and elimination pathways. Androgen Receptors enzalutamide ↓ doravirine Co-administration is contraindicated with enzalutamide. At least a 4-week cessation period is recommended prior to initiation of PIFELTRO. Anticonvulsants carbamazepine oxcarbazepine phenobarbital phenytoin ↓ doravirine Co-administration is contraindicated with these anticonvulsants. At least a 4-week cessation period is recommended prior to initiation of PIFELTRO. Antimycobacterials rifampin The interaction between PIFELTRO and the concomitant drug was evaluated in a clinical study. rifapentine ↓ doravirine Co-administration is contraindicated with rifampin or rifapentine . At least a 4-week cessation period is recommended prior to initiation of PIFELTRO. rifabutin ↓ doravirine Increase PIFELTRO dosage to one tablet twice daily when co-administered with rifabutin [see Dosage and Administration (2.2) ] . Cytotoxic Agents mitotane ↓ doravirine Co-administration is contraindicated with mitotane. At least a 4-week cessation period is recommended prior to initiation of PIFELTRO. HIV Antiviral Agents efavirenz etravirine nevirapine ↓ doravirine Use with efavirenz, etravirine, or nevirapine is not recommended. Herbal Products St. John's wort ↓ doravirine Co-administration is contraindicated with St. John's wort. At least a 4-week cessation period is recommended prior to initiation of PIFELTRO. No clinically significant changes in concentration were observed for doravirine when co-administered with the following agents: dolutegravir, TDF, lamivudine, elbasvir and grazoprevir, ledipasvir and sofosbuvir, ritonavir, ketoconazole, aluminum hydroxide/magnesium hydroxide/simethicone containing antacid, pantoprazole, and methadone [see Clinical Pharmacology (12.3) ]. 7.2 Effect of PIFELTRO on Other Drugs No clinically significant changes in concentration were observed for the following agents when co-administered with doravirine: dolutegravir, lamivudine, TDF, elbasvir and grazoprevir, ledipasvir and sofosbuvir, atorvastatin, an oral contraceptive containing ethinyl estradiol and levonorgestrel, metformin, methadone, and midazolam [see Clinical Pharmacology (12.3) ] .

8 USE IN SPECIFIC POPULATIONS Pediatrics: Not recommended for patients weighing less than 35 kg. ( 8.4 ) 8.1 Pregnancy Pregnancy Exposure Registry There is a pregnancy exposure registry that monitors pregnancy outcomes in individuals exposed to PIFELTRO during pregnancy. Healthcare providers are encouraged to register patients by calling the Antiretroviral Pregnancy Registry (APR) at 1-800-258-4263. Risk Summary No adequate human data are available to establish whether or not PIFELTRO poses a risk to pregnancy outcomes. In animal reproduction studies, no adverse developmental effects were observed when doravirine was administered at exposures ≥8 times the exposure in humans at the recommended human dose (RHD) of PIFELTRO ( see Data ). The background rate of major birth defects is 2.7% in a U.S. reference population of the Metropolitan Atlanta Congenital Defects Program (MACDP). The rate of miscarriage is not reported in the APR. The estimated background rate of miscarriage in the clinically recognized pregnancies in the U.S. general population is 15-20%. Methodological limitations of the APR include the use of MACDP as the external comparator group. The MACDP population is not disease-specific, evaluates individuals and infants from the limited geographic area, and does not include outcomes for births that occurred at less than 20 weeks gestation. Data Animal Data Doravirine was administered orally to pregnant rabbits (up to 300 mg/kg/day on gestation days (GD) 7 to 20) and rats (up to 450 mg/kg/day on GD 6 to 20 and separately from GD 6 to lactation/postpartum day 20). No significant toxicological effects on embryo-fetal (rats and rabbits) or pre/post-natal (rats) development were observed at exposures (AUC) approximately 9 times (rats) and 8 times (rabbits) the exposure in humans at the RHD. Doravirine was transferred to the fetus through the placenta in embryo-fetal studies, with fetal plasma concentrations of up to 40% (rabbits) and 52% (rats) that of maternal concentrations observed on GD 20. 8.2 Lactation Risk Summary It is unknown whether doravirine is present in human milk, affects human milk production, or has effects on the breastfed infant. Doravirine is present in the milk of lactating rats ( see Data ). Potential risks of breastfeeding include: (1) HIV-1 transmission (in HIV-1-negative infants), (2) developing viral resistance (in HIV-1-positive infants), and (3) serious adverse reactions in a breastfed infant similar to those seen in adults. Data Doravirine was excreted into the milk of lactating rats following oral administration (450 mg/kg/day) from GD 6 to lactation day 14, with milk concentrations approximately 1.5 times that of maternal plasma concentrations observed 2 hours post dose on lactation day 14. 8.4 Pediatric Use The safety and efficacy of PIFELTRO for the treatment of HIV-1 infection have been established in pediatric patients weighing at least 35 kg [see Indications and Usage (1) and Dosage and Administration (2.1) ]. Use of PIFELTRO in this group is supported by evidence from adequate and well-controlled trials in adults and an open-label trial in virologically-suppressed or treatment-naïve pediatric participants 12 to less than 18 years of age. The safety, efficacy, and exposure of doravirine in these pediatric participants were similar to that in adults [see Adverse Reactions (6.1) , Clinical Pharmacology (12.3) , and Clinical Studies (14.3) ]. Safety and efficacy of PIFELTRO in pediatric patients weighing less than 35 kg have not been established. 8.5 Geriatric Use Clinical trials of PIFELTRO did not include sufficient numbers of participants aged 65 years and over to determine whether they respond differently from younger participants. In general, caution should be exercised in the administration of PIFELTRO in elderly patients, reflecting the greater frequency of decreased hepatic, renal, or cardiac function, and of concomitant disease or other drug therapy [see Clinical Pharmacology (12.3) …

12.1 Mechanism of Action Doravirine is an antiretroviral drug [see Microbiology (12.4) ].

11 DESCRIPTION PIFELTRO is a film-coated tablet containing doravirine for oral administration. Doravirine is an HIV-1 non-nucleoside reverse transcriptase inhibitor (NNRTI). Each tablet contains 100 mg of doravirine as the active ingredient. The tablets include the following inactive ingredients: colloidal silicon dioxide, croscarmellose sodium, hypromellose acetate succinate, lactose monohydrate, magnesium stearate, and microcrystalline cellulose. The tablets are film coated with a coating material containing the following inactive ingredients: hypromellose, lactose monohydrate, titanium dioxide, and triacetin. The coated tablets are polished with carnauba wax. The chemical name for doravirine is 3-chloro-5-[[1-[(4,5-dihydro-4-methyl-5-oxo-1 H -1,2,4-triazol-3-yl)methyl]-1,2-dihydro-2-oxo-4-(trifluoromethyl)-3-pyridinyl]oxy]benzonitrile. It has a molecular formula of C 17 H 11 ClF 3 N 5 O 3 and a molecular weight of 425.75. It has the following structural formula: Doravirine is practically insoluble in water. Chemical Structure

16 HOW SUPPLIED/STORAGE AND HANDLING Each PIFELTRO tablet contains 100 mg of doravirine, is white, oval-shaped and film-coated, and is debossed with the corporate logo and 700 on one side and plain on the other side. Each bottle contains 30 tablets (NDC 0006-3069-01) with silica gel desiccant and is closed with a child-resistant closure. Store PIFELTRO in the original bottle. Keep the bottle tightly closed to protect from moisture. Do not remove the desiccant. Store PIFELTRO at 20°C to 25°C (68°F to 77°F); excursions permitted to 15°C to 30°C (59°F to 86°F) [see USP Controlled Room Temperature].