ZELBORAF Vemurafenib 240 mg Tablet, Film Coated, 112-count — NDC 50242-090-02 (Billing 50242-0090-02)

12 CLINICAL PHARMACOLOGY

12.1Mechanism of Action Vemurafenib is a low molecular weight, orally available inhibitor of some mutated forms of BRAF serine- threonine kinase, including BRAF V600E. Vemurafenib also inhibits other kinases in vitro such as CRAF, ARAF, wild-type BRAF, SRMS, ACK1, MAP4K5, and FGR at similar concentrations. Some mutations in the BRAF gene including V600E result in constitutively activated BRAF proteins, which can cause cell proliferation in the absence of growth factors that would normally be required for proliferation.

Vemurafenib has anti-tumor effects in cellular and animal models of melanomas with mutated BRAF V600E.

12.2Pharmacodynamics Cardiac Electrophysiology In a multi-center, open-label, single-arm study in 132 patients with BRAF V600E mutation-positive metastatic melanoma, patients administered vemurafenib 960 mg orally twice daily did not experience large changes in mean QTc interval (i.e., > 20 ms) from baseline. Vemurafenib is associated with concentration- dependent QTc interval prolongation. The largest mean change from baseline in the first month of treatment occurred at 2 hours post-dose on Day 15—an increase of 12.8 ms (upper boundary of the two-sided 90% confidence interval of 14.9 ms).

In the first 6 months of treatment, the largest observed mean change from baseline occurred at a pre-dose time point—an increase of 15.1 ms (upper boundary of the two-sided 90% confidence interval of 17.7 ms).

12.3Pharmacokinetics The pharmacokinetics of vemurafenib were determined in patients with BRAF mutation-positive metastatic melanoma following 15 days of 960 mg twice daily with dosing approximately 12 hours apart. The population pharmacokinetic analysis pooled data from 458 patients. At steady-state, vemurafenib exhibits linear pharmacokinetics within the 240 mg to 960 mg dose range.

Absorption The mean bioavailability of vemurafenib at steady state was 64% (56% CV). The median time to reach maximum plasma vemurafenib concentration (T max ) was 3 hours following multiple doses. The mean (± SD) C max and AUC 0-12 were 62 ± 17 µg/mL and 601 ± 170 µg*h/mL, respectively.

The median accumulation ratio estimate from the population pharmacokinetic analysis for the twice daily regimen is 7.4, with steady-state achieved at approximately 15 to 22 days. In clinical trials, vemurafenib was administered without regard to food. A food effect study has demonstrated that a single dose of vemurafenib administered with a high-fat meal increased AUC by approximately 5-fold, increased C max by 2.5-fold, and delayed T max by approximately 4 hours as compared to the fasted state.

QTc prolongation may occur with increased exposures as vemurafenib is associated with concentration-dependent QTc interval prolongation [see Clinical Pharmacology (12.2) ] . Distribution Vemurafenib is highly bound (> 99%) to human albumin and alpha-1 acid glycoprotein plasma proteins. The population apparent volume of distribution is estimated to be 106 L (with 66% inter-patient variability).

Metabolism Following oral administration of 960 mg of 14 C-vemurafenib, mean data showed that vemurafenib and its metabolites represented 95% and 5% of the components in plasma over 48 hours, respectively. Elimination Following oral administration of 960 mg of 14 C-vemurafenib, approximately 94% of the radioactive dose was recovered in feces and approximately 1% was recovered in the urine. The population apparent clearance is estimated to be 31 L/day (with 32% inter-patient variability).

The median elimination half-life estimate for vemurafenib is 57 hours (the 5th and 95th percentile range is 30 to 120 hours). Specific Populations Hepatic Impairment : The pharmacokinetics of vemurafenib were examined in patients with metastatic melanoma enrolled in the clinical trials with normal hepatic function (n=158, total bilirubin ≤ ULN) and mild (n=58, total bilirubin 1.0–1.5 × ULN), moderate (n=27, total bilirubin 1.5–3 × ULN), or severe (n=3, total biliru… [Excerpted — this section continues on DailyMed.]

12.1Mechanism of Action Vemurafenib is a low molecular weight, orally available inhibitor of some mutated forms of BRAF serine- threonine kinase, including BRAF V600E. Vemurafenib also inhibits other kinases in vitro such as CRAF, ARAF, wild-type BRAF, SRMS, ACK1, MAP4K5, and FGR at similar concentrations. Some mutations in the BRAF gene including V600E result in constitutively activated BRAF proteins, which can cause cell proliferation in the absence of growth factors that would normally be required for proliferation.

Vemurafenib has anti-tumor effects in cellular and animal models of melanomas with mutated BRAF V600E.

12.3Pharmacokinetics The pharmacokinetics of vemurafenib were determined in patients with BRAF mutation-positive metastatic melanoma following 15 days of 960 mg twice daily with dosing approximately 12 hours apart. The population pharmacokinetic analysis pooled data from 458 patients. At steady-state, vemurafenib exhibits linear pharmacokinetics within the 240 mg to 960 mg dose range.

Absorption The mean bioavailability of vemurafenib at steady state was 64% (56% CV). The median time to reach maximum plasma vemurafenib concentration (T max ) was 3 hours following multiple doses. The mean (± SD) C max and AUC 0-12 were 62 ± 17 µg/mL and 601 ± 170 µg*h/mL, respectively.

The median accumulation ratio estimate from the population pharmacokinetic analysis for the twice daily regimen is 7.4, with steady-state achieved at approximately 15 to 22 days. In clinical trials, vemurafenib was administered without regard to food. A food effect study has demonstrated that a single dose of vemurafenib administered with a high-fat meal increased AUC by approximately 5-fold, increased C max by 2.5-fold, and delayed T max by approximately 4 hours as compared to the fasted state.

QTc prolongation may occur with increased exposures as vemurafenib is associated with concentration-dependent QTc interval prolongation [see Clinical Pharmacology (12.2) ] . Distribution Vemurafenib is highly bound (> 99%) to human albumin and alpha-1 acid glycoprotein plasma proteins. The population apparent volume of distribution is estimated to be 106 L (with 66% inter-patient variability).

Metabolism Following oral administration of 960 mg of 14 C-vemurafenib, mean data showed that vemurafenib and its metabolites represented 95% and 5% of the components in plasma over 48 hours, respectively. Elimination Following oral administration of 960 mg of 14 C-vemurafenib, approximately 94% of the radioactive dose was recovered in feces and approximately 1% was recovered in the urine. The population apparent clearance is estimated to be 31 L/day (with 32% inter-patient variability).

The median elimination half-life estimate for vemurafenib is 57 hours (the 5th and 95th percentile range is 30 to 120 hours). Specific Populations Hepatic Impairment : The pharmacokinetics of vemurafenib were examined in patients with metastatic melanoma enrolled in the clinical trials with normal hepatic function (n=158, total bilirubin ≤ ULN) and mild (n=58, total bilirubin 1.0–1.5 × ULN), moderate (n=27, total bilirubin 1.5–3 × ULN), or severe (n=3, total bilirubin > 3 × ULN) hepatic impairment. Patients received vemurafenib 960 mg orally twice daily.

The apparent clearance of vemurafenib in patients with mild and moderate hepatic impairment was similar to that in patients with normal hepatic function. The appropriate dose for patients with severe hepatic impairment cannot be determined as clinical and pharmacokinetic data were available for only three patients [see Use in Specific Populations (8.6) ]. Renal Impairment : The pharmacokinetics of vemurafenib were examined in patients with metastatic melanoma enrolled in the clinical trials with normal renal function (CLcr ≥ 90 mL/min) and mild (n=94, CLcr > 60 to 89 mL/min), moderate (n=11, CLcr 30 to 59 mL/min) or severe (n=1, CLcr < 29 mL/min) renal impairment.

Patients received vemurafenib 960 mg orally twice daily. The apparent clearance of vemurafenib in patients with mild and moderate renal impairment was similar to that in patients with normal renal function. The appropriate dose for patients with severe renal impairment cannot be determined as clinical and pharmacokinetic data were available for only one patient [see Use in Specific Populations (8.7) ].

Age, Body Weight, Sex, and Race : Based on the population pharmacokinetic analysis, age, body weight, and sex do not have a clinically important effect on the exposure of vemurafenib. There are insufficient data to evaluate potential differences in the pharmacokinetics of vemurafenib by rac… [Excerpted — this section continues on DailyMed.]

12.2Pharmacodynamics Cardiac Electrophysiology In a multi-center, open-label, single-arm study in 132 patients with BRAF V600E mutation-positive metastatic melanoma, patients administered vemurafenib 960 mg orally twice daily did not experience large changes in mean QTc interval (i.e., > 20 ms) from baseline. Vemurafenib is associated with concentration- dependent QTc interval prolongation. The largest mean change from baseline in the first month of treatment occurred at 2 hours post-dose on Day 15—an increase of 12.8 ms (upper boundary of the two-sided 90% confidence interval of 14.9 ms).

In the first 6 months of treatment, the largest observed mean change from baseline occurred at a pre-dose time point—an increase of 15.1 ms (upper boundary of the two-sided 90% confidence interval of 17.7 ms).

14 CLINICAL STUDIES Treatment-Naïve Patients with BRAF V600E Mutation-Positive Unresectable or Metastatic Melanoma Trial 1, an international, open-label, randomized controlled trial, equally allocated 675 patients with treatment-naive, BRAF V600E mutation-positive unresectable or metastatic melanoma, as detected by the cobas ® 4800 BRAF V600 Mutation Test, to receive ZELBORAF 960 mg by mouth twice daily (n=337) or dacarbazine 1000 mg/m 2 intravenously on Day 1 every 3 weeks (n=338). Randomization stratification factors were disease stage, lactate dehydrogenase (LDH), ECOG performance status, and geographic region.

Treatment continued until disease progression, unacceptable toxicity, and/or consent withdrawal. The major efficacy outcome measures of the trial were overall survival (OS) and investigator-assessed progression-free survival (PFS). Other outcome measures included confirmed investigator-assessed best overall response rate.

Baseline characteristics were balanced between treatment groups. Most patients were male (56%) and Caucasian (99%), the median age was 54 years (24% were ≥ 65 years), all patients had ECOG performance status of 0 or 1, and the majority of patients had metastatic disease (95%). Trial 1 demonstrated statistically significant increases in overall survival and progression-free survival in the ZELBORAF arm compared to the dacarbazine control arm.

Table 5 and Figure 1 summarize the efficacy results. Table 5 Efficacy of ZELBORAF in Treatment-Naïve Patients with BRAF V600E Mutation-Positive Melanoma As detected by the cobas ® 4800 BRAF V600 Mutation Test ZELBORAF (n=337) Dacarbazine (n=338) p-value Unstratified log-rank test Overall Survival Number of Deaths Total of 200 deaths (ZELBORAF median follow-up 6.2 months) 78 (23%) 122 (36%) Hazard Ratio (95% CI) Hazard ratio estimated using Cox model; a hazard ratio of < 1 favors ZELBORAF 0.47 (0.35, 0.62) < 0.0001 Updated Median Survival (months) (95 % CI) Kaplan-Meier estimate , Updated based on 478 deaths (ZELBORAF median follow-up 13.4 months) 13.6 (12.0, 15.3) 10.3 (9.1, 12.8) - Progression-Free Survival Hazard Ratio (95% CI) 0.26 (0.20, 0.33) < 0.0001 Median PFS (months) (95% CI) 5.3 (4.9, 6.6) 1.6 (1.6, 1.7) - Figure 1 Kaplan-Meier Curves of Overall Survival – Treatment-Naïve Patients The confirmed, investigator-assessed best overall response rate was 48.4% (95% CI: 41.6%, 55.2%) in the ZELBORAF arm compared to 5.5% (95% CI: 2.8%, 9.3%) in the dacarbazine arm.

There were 2 complete responses (0.9%) and 104 partial responses (47.4%) in the ZELBORAF arm and all 12 responses were partial responses (5.5%) in the dacarbazine arm. Figure 1 Patients with BRAF V600E Mutation-Positive Metastatic Melanoma Who Received Prior Systemic Therapy In a single-arm, multicenter, multinational trial (Trial 2), 132 patients with BRAF V600E mutation-positive metastatic melanoma, as detected by the cobas ® 4800 BRAF V600 Mutation Test, who had received at least one prior systemic therapy, received ZELBORAF 960 mg by mouth twice daily.

The median age was 52 years with 19% of patients being older than 65 years. The majority of patients were male (61%) and Caucasian (99%). Forty-nine percent of patients received ≥ 2 prior therapies.

The median duration of follow-up was 6.87 months (range, 0.6 to 11.3). The confirmed best overall response rate as assessed by an independent review committee (IRC) was 52% (95% CI: 43%, 61%). There were 3 complete responses (2.3%) and 66 partial responses (50.0%).

The median time to response was 1.4 months with 75% of responses occurring by month 1.6 of treatment. The median duration of response by IRC was 6.5 months (95% CI: 5.6, not reached). Patients with BRAF V600E Mutation-Positive Melanoma with Brain Metastases The activity of ZELBORAF for the treatment of BRAF V600E mutation-positive melanoma, metastatic to the brain was evaluated in an open-label, multicenter, single-arm, two cohort trial (Trial 3).

All patients received ZELBORAF 960 mg orally… [Excerpted — this section continues on DailyMed.]

13 NONCLINICAL TOXICOLOGY

13.1Carcinogenesis, Mutagenesis, Impairment of Fertility There have been no formal studies conducted assessing the carcinogenic potential of vemurafenib. ZELBORAF increased the development of cutaneous squamous cell carcinomas in patients in clinical trials. Vemurafenib did not cause genetic damage when tested in in vitro assays (bacterial mutation [AMES Assay], human lymphocyte chromosome aberration) or in the in vivo rat bone marrow micronucleus test.

No specific studies with vemurafenib have been conducted in animals to evaluate the effect on fertility; nevertheless, no histopathological findings were noted in reproductive organs in males and females in repeat-dose toxicology studies in rats at doses up to 450 mg/kg/day (approximately 0.6 and 1.6 times the human exposure based on AUC in males and females, respectively) and dogs at doses up to 450 mg/kg/day (approximately 0.3 times the human clinical exposure based on AUC in both males and females, respectively).

13.2Animal Toxicology and/or Pharmacology Consistent with the increased incidence of cutaneous squamous cell carcinomas in patients treated with vemurafenib, the treatment of mice implanted with human cuSCC cells with vemurafenib caused a dose- dependent acceleration of the growth of the implanted tumors.