Tofacitinib 11 mg Tablet, Film Coated, Extended Release, 30-count — NDC 42799-970-30 (Billing 42799-0970-30)

12 CLINICAL PHARMACOLOGY

12.1Mechanism of Action Tofacitinib is a Janus kinase (JAK) inhibitor. JAKs are intracellular enzymes which transmit signals arising from cytokine or growth factor-receptor interactions on the cellular membrane to influence cellular processes of hematopoiesis and immune cell function. Within the signaling pathway, JAKs phosphorylate and activate Signal Transducers and Activators of Transcription (STATs) which modulate intracellular activity including gene expression.

Tofacitinib modulates the signaling pathway at the point of JAKs, preventing the phosphorylation and activation of STATs. JAK enzymes transmit cytokine signaling through pairing of JAKs (e.g., JAK1/JAK3, JAK1/JAK2, JAK1/TyK2, JAK2/JAK2). Tofacitinib inhibited the in vitro activities of JAK1/JAK2, JAK1/JAK3, and JAK2/JAK2 combinations with IC 50 of 406, 56, and 1377 nM, respectively.

However, the relevance of specific JAK combinations to therapeutic effectiveness is not known.

12.2Pharmacodynamics Treatment with tofacitinib was associated with dose-dependent reductions of circulating CD16/56+ natural killer cells, with estimated maximum reductions occurring at approximately 8-10 weeks after initiation of therapy. These changes generally resolved within 2-6 weeks after discontinuation of treatment. Treatment with tofacitinib was associated with dose-dependent increases in B cell counts.

Changes in circulating T-lymphocyte counts and T-lymphocyte subsets (CD3+, CD4+ and CD8+) were small and inconsistent. The clinical significance of these changes is unknown. Total serum IgG, IgM, and IgA levels after 6-month dosing in patients with rheumatoid arthritis (RA) were lower than in patients who received placebo; however, changes were small and not dose-dependent.

After treatment with tofacitinib in patients with RA, rapid decreases in serum C-reactive protein (CRP) were observed and maintained throughout dosing. Changes in CRP observed with tofacitinib treatment do not reverse fully within 2 weeks after discontinuation, indicating a longer duration of pharmacodynamic activity compared to the pharmacokinetic half-life. Similar changes in T cells, B cells, and serum CRP have been observed in patients with active psoriatic arthritis (PsA) although reversibility was not assessed.

Total serum immunoglobulins were not assessed in patients with active PsA.

12.3Pharmacokinetics Following oral administration of tofacitinib, peak plasma concentrations were reached within 0.5 hour - 1 hour, elimination half-life was about 3 hours and a dose-proportional increase in systemic exposure was observed in the therapeutic dosage range. Steady state concentrations were achieved in 24-48 hours with negligible accumulation after twice daily administration. Following oral administration of tofacitinib extended-release tablets, peak plasma concentrations were reached at 4 hours and half-life was about 6 to 8 hours.

Steady state concentrations were achieved within 48 hours with negligible accumulation after once daily administration. Table 7 describes the pharmacokinetic parameters of tofacitinib and tofacitinib extended-release tablets. Absorption Tofacitinib The absolute oral bioavailability of tofacitinib is 74%.

Coadministration of tofacitinib with a high-fat meal resulted in no changes in AUC while Cmax was reduced by 32%. In clinical trials, tofacitinib was administered without regard to meals [see Dosage and Administration (2.2) ]. Tofacitinib Extended-Release Tablets Coadministration of tofacitinib extended-release tablets 11 and 22 mg with a high-fat meal resulted in no changes in AUC while Cmax was increased by 27% and 19% respectively.

T max was extended by approximately 1 hour for both tofacitinib extended-release tablets 11 and 22 mg. Distribution After intravenous administration, the volume of distribution was 87 L. The protein binding of tofacitinib is approximately 40%.

Tofacitinib binds predominantly to albumin and does not appear to bind to α1-acid gly… [Excerpted — this section continues on DailyMed.]

12.1Mechanism of Action Tofacitinib is a Janus kinase (JAK) inhibitor. JAKs are intracellular enzymes which transmit signals arising from cytokine or growth factor-receptor interactions on the cellular membrane to influence cellular processes of hematopoiesis and immune cell function. Within the signaling pathway, JAKs phosphorylate and activate Signal Transducers and Activators of Transcription (STATs) which modulate intracellular activity including gene expression.

Tofacitinib modulates the signaling pathway at the point of JAKs, preventing the phosphorylation and activation of STATs. JAK enzymes transmit cytokine signaling through pairing of JAKs (e.g., JAK1/JAK3, JAK1/JAK2, JAK1/TyK2, JAK2/JAK2). Tofacitinib inhibited the in vitro activities of JAK1/JAK2, JAK1/JAK3, and JAK2/JAK2 combinations with IC 50 of 406, 56, and 1377 nM, respectively.

However, the relevance of specific JAK combinations to therapeutic effectiveness is not known.

12.3Pharmacokinetics Following oral administration of tofacitinib, peak plasma concentrations were reached within 0.5 hour - 1 hour, elimination half-life was about 3 hours and a dose-proportional increase in systemic exposure was observed in the therapeutic dosage range. Steady state concentrations were achieved in 24-48 hours with negligible accumulation after twice daily administration. Following oral administration of tofacitinib extended-release tablets, peak plasma concentrations were reached at 4 hours and half-life was about 6 to 8 hours.

Steady state concentrations were achieved within 48 hours with negligible accumulation after once daily administration. Table 7 describes the pharmacokinetic parameters of tofacitinib and tofacitinib extended-release tablets. Absorption Tofacitinib The absolute oral bioavailability of tofacitinib is 74%.

Coadministration of tofacitinib with a high-fat meal resulted in no changes in AUC while Cmax was reduced by 32%. In clinical trials, tofacitinib was administered without regard to meals [see Dosage and Administration (2.2) ]. Tofacitinib Extended-Release Tablets Coadministration of tofacitinib extended-release tablets 11 and 22 mg with a high-fat meal resulted in no changes in AUC while Cmax was increased by 27% and 19% respectively.

T max was extended by approximately 1 hour for both tofacitinib extended-release tablets 11 and 22 mg. Distribution After intravenous administration, the volume of distribution was 87 L. The protein binding of tofacitinib is approximately 40%.

Tofacitinib binds predominantly to albumin and does not appear to bind to α1-acid glycoprotein. Tofacitinib distributes equally between red blood cells and plasma. Metabolism and Excretion Clearance mechanisms for tofacitinib are approximately 70% hepatic metabolism and 30% renal excretion of the parent drug.

The metabolism of tofacitinib is primarily mediated by CYP3A4 with minor contribution from CYP2C19. In a human radiolabeled study, more than 65% of the total circulating radioactivity was accounted for by unchanged tofacitinib, with the remaining 35% attributed to 8 metabolites, each accounting for less than 8% of total radioactivity. The pharmacologic activity of tofacitinib is attributed to the parent molecule.

Pharmacokinetics in Patients with RA, PsA, AS, and UC Population pharmacokinetic (PK) analyses indicated that PK characteristics were similar between patients with RA, PsA, ankylosing spondylitis, and UC. The coefficient of variation (%) in AUC of tofacitinib were generally similar across different disease patients, ranging from 22% to 34% (Table 8). Specific Populations Covariate evaluation as part of population PK analyses in adult patient populations indicated no clinically relevant change in tofacitinib exposure, after accounting for differences in renal function (i.e., creatinine clearance) between patients, based on age, weight, biological sex and race (Figure 1).

An approximately linear relationship between body weight and volume of distribution was observed, resulting in higher peak (C max ) and lower trough (C min ) concentrations in lighter patients. However, this difference is not considered to be clinically relevant. The effect of renal and hepatic impairment and other intrinsic factors on the PK of tofacitinib is shown in Figure 1.

Note: Reference values for weight, age, biological sex, and race comparisons are 70 kg, 55 years, male, and white, respectively; reference groups for renal and hepatic impairment data are patients with normal renal and hepatic function. Renal function was estimated using creatinine clearance by Cockcroft-Gault method and hepatic function was estimated using Child-Pugh scoring method. In patients with end-stage renal disease maintained on hemodialysis, mean AUC was approximately 40% higher compared with historical healthy subject data, consistent with approximately 30% contribution of renal clearance to the total clearance of tofacitinib [see Dosage and Adminis… [Excerpted — this section continues on DailyMed.]

12.2Pharmacodynamics Treatment with tofacitinib was associated with dose-dependent reductions of circulating CD16/56+ natural killer cells, with estimated maximum reductions occurring at approximately 8-10 weeks after initiation of therapy. These changes generally resolved within 2-6 weeks after discontinuation of treatment. Treatment with tofacitinib was associated with dose-dependent increases in B cell counts.

Changes in circulating T-lymphocyte counts and T-lymphocyte subsets (CD3+, CD4+ and CD8+) were small and inconsistent. The clinical significance of these changes is unknown. Total serum IgG, IgM, and IgA levels after 6-month dosing in patients with rheumatoid arthritis (RA) were lower than in patients who received placebo; however, changes were small and not dose-dependent.

After treatment with tofacitinib in patients with RA, rapid decreases in serum C-reactive protein (CRP) were observed and maintained throughout dosing. Changes in CRP observed with tofacitinib treatment do not reverse fully within 2 weeks after discontinuation, indicating a longer duration of pharmacodynamic activity compared to the pharmacokinetic half-life. Similar changes in T cells, B cells, and serum CRP have been observed in patients with active psoriatic arthritis (PsA) although reversibility was not assessed.

Total serum immunoglobulins were not assessed in patients with active PsA.

14 CLINICAL STUDIES

14.1Clinical Studies in Rheumatoid Arthritis The rheumatoid arthritis (RA) clinical development program with tofacitinib included six randomized controlled trials in adults with moderate to severe active RA. Trial Design Study RA-I (NCT00814307) was a 6-month monotherapy trial in which 610 patients with moderate to severe active RA who had an inadequate response to a DMARD (nonbiologic or biologic) received tofacitinib 5 mg or 10 mg twice daily or placebo added to their background DMARD. At the Month 3 visit, all patients randomized to placebo treatment were switched in a blinded fashion to a second predetermined treatment of tofacitinib 5 mg or 10 mg twice daily.

The primary endpoints at Month 3 were the proportion of patients who achieved an ACR20 response, changes in Health Assessment Questionnaire – Disability Index (HAQ-DI), and rates of Disease Activity Score DAS28-4(ESR) less than 2.6. Study RA-II (NCT00856544) was a 12-month trial in which 792 patients with moderate to severe active RA who had an inadequate response to a nonbiologic DMARD received tofacitinib 5 mg or 10 mg twice daily or placebo added to background DMARD treatment (excluding potent immunosuppressive treatments such as azathioprine or cyclosporine).

At the Month 3 visit, nonresponding patients were switched in a blinded fashion to a second predetermined treatment of tofacitinib 5 mg or 10 mg twice daily. At the end of Month 6, all patients treated with placebo were switched to their second predetermined tofacitinib treatment in a blinded fashion. The primary endpoints were the proportion of patients who achieved an ACR20 response at Month 6, changes in HAQ-DI at Month 3, and rates of DAS28-4(ESR) less than 2.6 at Month 6.

Study RA-III (NCT00853385) was a 12-month trial in 717 patients with moderate to severe active RA who had an inadequate response to methotrexate (MTX). Patients received tofacitinib 5 mg or 10 mg orally twice daily, adalimumab 40 mg subcutaneously every other week, or placebo added to background MTX. Patients treated with placebo were switched as in Study RA-II.

The primary endpoints were the proportion of patients who achieved an ACR20 response at Month 6, HAQ-DI at Month 3, and DAS28-4(ESR) less than 2.6 at Month 6. Study RA-IV (NCT00847613) was a 2-year trial with a planned analysis at 1 year in which 797 patients with moderate to severe active RA who had an inadequate response to MTX received tofacitinib 5 mg or 10 mg twice daily or placebo added to background MTX. Patients treated with placebo were switched as in Study RA-II.

The primary endpoints were the proportion of patients who achieved an ACR20 response at Month 6, mean change from baseline in van der Heijde-modified total Sharp Score (mTSS) at Month 6, HAQ-DI at Month 3, and DAS28-4(ESR) less than 2.6 at Month 6. Study RA-V (NCT00960440) was a 6-month trial in which 399 patients with moderate to severe active RA who had an inadequate response to at least one approved TNF blocking biological product received tofacitinib 5 mg or 10 mg twice daily or placebo added to background MTX. At the Month 3 visit, all patients randomized to placebo treatment were switched in a blinded fashion to a second predetermined treatment of tofacitinib 5 or 10 mg twice daily.

The primary endpoints at Month 3 were the proportion of patients who achieved an ACR20 response, HAQ-DI, and DAS28-4(ESR) less than 2.6. Study RA-VI (NCT01039688) was a 2-year monotherapy trial with a planned analysis at 1 year in which 952 MTX-naïve patients with moderate to severe active RA received tofacitinib 5 or 10 mg twice daily or MTX dose-titrated over 8 weeks to 20 mg weekly. The primary endpoints were mean change from baseline in van der Heijde-modified Total Sharp Score (mTSS) at Month 6 and the proportion of patients who achieved an ACR70 response at Month 6.

Although other dosages have been studied, the recommended dosage of tofacitinib is 5 mg twice daily. Tofacitinib 10 mg twice daily is… [Excerpted — this section continues on DailyMed.]

13 NONCLINICAL TOXICOLOGY

13.1Carcinogenesis, Mutagenesis, Impairment of Fertility In a 39-week toxicology study in monkeys, tofacitinib at exposure levels approximately 6 times the recommended dose of 5 mg twice daily, and approximately 3 times the 10 mg twice daily dose (on an AUC basis at oral doses of 5 mg/kg twice daily) produced lymphomas. No lymphomas were observed in this study at exposure levels 1 times the recommended dose of 5 mg twice daily, and approximately 0.5 times the 10 mg twice daily dose (on an AUC basis at oral doses of 1 mg/kg twice daily).

The carcinogenic potential of tofacitinib was assessed in 6-month rasH2 transgenic mouse carcinogenicity and 2-year rat carcinogenicity studies. Tofacitinib, at exposure levels approximately 34 times the recommended dose of 5 mg twice daily, and approximately 17 times the 10 mg twice daily dose (on an AUC basis at oral doses of 200 mg/kg/day) was not carcinogenic in mice. In the 24-month oral carcinogenicity study in Sprague-Dawley rats, tofacitinib caused benign Leydig cell tumors, hibernomas (malignancy of brown adipose tissue), and benign thymomas at doses greater than or equal to 30 mg/kg/day (approximately 42 times the exposure levels at the recommended dose of 5 mg twice daily, and approximately 21 times the 10 mg twice daily dose on an AUC basis).

The relevance of benign Leydig cell tumors to human risk is not known. Tofacitinib was not mutagenic in the bacterial reverse mutation assay. It was positive for clastogenicity in the in vitro chromosome aberration assay with human lymphocytes in the presence of metabolic enzymes, but negative in the absence of metabolic enzymes.

Tofacitinib was negative in the in vivo rat micronucleus assay and in the in vitro CHO-HGPRT assay and the in vivo rat hepatocyte unscheduled DNA synthesis assay. In rats, tofacitinib at exposure levels approximately 17 times the recommended dose of 5 mg twice daily, and approximately 8.3 times the 10 mg twice daily dose (on an AUC basis at oral doses of 10 mg/kg/day) reduced female fertility due to increased post-implantation loss. There was no impairment of female rat fertility at exposure levels of tofacitinib equal to the recommended dose of 5 mg twice daily, and approximately 0.5 times the 10 mg twice daily dose (on an AUC basis at oral doses of 1 mg/kg/day).

Tofacitinib exposure levels at approximately 133 times the recommended dose of 5 mg twice daily, and approximately 67 times the 10 mg twice daily dose (on an AUC basis at oral doses of 100 mg/kg/day) had no effect on male fertility, sperm motility, or sperm concentration.