Randomized, Multicenter Study to Assess the Effects of Different Doses of Sildenafil on Mortality in Adults With Pulmonary Arterial Hypertension.

BACKGROUND: Sildenafil, approved for pulmonary arterial hypertension (PAH), has a recommended adult dose of 20 mg TID, with a previously approved 5-mg TID dose by the US Food and Drug Administration. Safety concerns arose because of common off-label use of higher doses, particularly after pediatric data linked higher doses to increased mortality. To assess this, the Food and Drug Administration mandated a study evaluating the effects of various sildenafil doses on mortality in adults with PAH. METHODS: This randomized, double-blind study compared sildenafil at doses of 5, 20, or 80 mg TID in adults with PAH. The primary objective was noninferiority of 80 mg of sildenafil versus 5 mg for all-cause mortality. Secondary end points included time to clinical worsening and change in 6-minute walk distance at 6 months. Interim analyses were planned at 50% and 75% of the anticipated mortality events. Safety and tolerability were assessed in the intention-to-treat population. RESULTS: The study was halted after the first interim analysis, demonstrating noninferiority for 80 mg of sildenafil versus 5 mg. Of 385 patients enrolled across all dose groups, 78 died. The primary analysis showed a hazard ratio of 0.51 (99.7% CI, 0.22-1.21; P<0.001 for noninferiority) for overall survival comparing 80 mg of sildenafil with 5 mg. Time to clinical worsening favored 80 mg of sildenafil compared with 5 mg (hazard ratio, 0.44 [99.7% CI, 0.22-0.89]; P<0.001). Sildenafil at 80 mg improved 6-minute walk distance from baseline at 6 months compared with 5 mg (least square mean change, 18.9 m [95% CI, 2.99-34.86]; P=0.0201). No significant differences were found between 80 mg of sildenafil and 20 mg in mortality, clinical worsening, and 6-minute walk distance. Adverse event-related drug discontinuations were numerically higher with 80 mg of sildenafil. CONCLUSIONS: Sildenafil at 80 mg was noninferior to sildenafil at 5 mg when examining all-cause mortality in adults with PAH. Secondary efficacy end points favored 80 mg of sildenafil over 5 mg. On the basis of these findings, the Food and Drug Administration recently revoked the approval of 5 mg of sildenafil for adults with PAH, reinforced 20 mg TID as the recommended dose, and now allows dose titration up to 80 mg TID, if needed. REGISTRATION: URL: https://www.clinicaltrials.gov; Unique identifier: NCT02060487.

Bioequivalence Studies of Sildenafil Citrate Orodispersible Film Administered with and without Water vs ViagraⓇ Film-Coated Tablets in Healthy Male Volunteers.

Background: Orodispersible film (ODF) formulation offers ease of use, convenience of administration, and other advantages, especially for patients who have difficulty in swallowing or are on liquid restriction compared with conventional oral formulations for the treatment of erectile dysfunction. Objectives: These studies compared the bioequivalence of 50 mg sildenafil citrate ODF formulation (test drug) with the marketed 50 mg sildenafil citrate film-coated tablet (FCT) (ViagraⓇ; Pfizer, New York, NY) (reference drug), with and without water in 2 randomized cross-over studies. Methods: Two randomized cross-over studies were conducted. The first study explored the bioequivalence of test drug administered with and without water compared with the reference drug with water. The second study investigated the bioequivalence of test drug, without water, compared with the reference drug with water. Forty-two and 80 healthy male volunteers were recruited in the first and second study, respectively. All volunteers fasted for 10 hours pre-dose. A 1-day washout period between doses was observed. Blood samples were collected at both before (up to 120 minutes before dosing) and after dosing (at different intervals up to 14 hours) stages. Statistical analyses on pharmacokinetic parameters were performed. Safety and tolerability for both the formulations were evaluated. Results: In the first study, bioequivalence was demonstrated for sildenafil citrate ODF administered with water when compared with the ViagraⓇ FCT. The ratios of adjusted geometric means (90% confidence interval (CI)) were maximum plasma concentration: 1.02 (94.91-108.78) and area under the plasma concentration-time curve: 1.09 (104.49-113.21) for sildenafil citrate ODF administered with water vs ViagraⓇ FCT. These ratios were within the bioequivalence acceptance range of 80% to 125%, indicating that the bioequivalence criteria were met. The pharmacokinetic parameters for the second study also showed bioequivalence for sildenafil citrate ODF (without water) compared with ViagraⓇ FCT. The ratios of adjusted geometric means (90% CI) were maximum plasma concentration: 1.02 (95.47-109.36) and area under the plasma concentration-time curve: 1.06 (103.42-108.40) for sildenafil citrate ODF administered without water vs ViagraⓇ FCT. Adverse events in both the studies occurred at similar rates for the 2 formulations and were mild in intensity. Conclusions: These results suggest that the new ODF formulation can be used interchangeably with the marketed FCT formulation. Sildenafil citrate ODF administered with and without water met bioequivalence criteria compared with ViagraⓇ FCT administered with water under fasted conditions in healthy adult male volunteers. The new ODF formulation can be used as a suitable alternative to the conventional oral solid dosage form.

Long-term Efficacy, Safety, and Immunogenicity of the Infliximab (IFX) Biosimilar, PF-06438179/GP1111, in Patients with Rheumatoid Arthritis After Switching from Reference IFX or Continuing Biosimilar Therapy: Week 54-78 Data From a Randomized, Double-Blind, Phase III Trial.

OBJECTIVE: Our objective was to evaluate the long-term efficacy, safety, and immunogenicity of the infliximab biosimilar, PF-06438179/GP1111 (PF-SZ-IFX), in patients with rheumatoid arthritis (RA) who continued biosimilar treatment throughout 78 weeks or who switched from reference infliximab (Remicade®) sourced from the EU (IFX-EU) at week 30 or week 54 in the REFLECTIONS B537-02 study. METHODS: In this phase III, double-blind, active-controlled study, patients with moderate-to-severe active RA were initially randomized to PF-SZ-IFX or IFX-EU, each with methotrexate (treatment period [TP] 1; N = 650). At week 30, patients receiving PF-SZ-IFX continued PF-SZ-IFX; patients receiving IFX-EU were re-randomized to continue IFX-EU or switch to PF-SZ-IFX (TP2; n = 566). From weeks 54 to 78, all patients received open-label treatment with PF-SZ-IFX (TP3; n = 505). Efficacy, safety, and immunogenicity data were analyzed during TP3. RESULTS: Efficacy was sustained and comparable across groups at week 78, with American College of Rheumatology criteria for ≥ 20% clinical improvement response rates of 75.9% (biosimilar group), 77.8% (week 30 switch group), and 68.3% (week 54 switch group). The incidence of treatment-emergent adverse events was 28.9%, 29.4%, and 30.2%, respectively. The proportion of patients who were antidrug antibody (ADA) positive and neutralizing antibody positive (as a percentage of ADA-positive patients) was stable and comparable between groups. CONCLUSIONS: Results to week 78 continue to support the efficacy, safety, and immunogenicity of PF-SZ-IFX in patients with moderate-to-severe active RA. There were no clinically meaningful differences between groups, independent of a single treatment transition from IFX-EU to PF-SZ-IFX at week 30 or week 54. TRIAL REGISTRATION NUMBER: NCT02222493.

Randomised, double-blind, phase III study comparing the infliximab biosimilar, PF-06438179/GP1111, with reference infliximab: efficacy, safety and immunogenicity from week 30 to week 54.

Objective: To investigate the efficacy, safety and immunogenicity of PF-06438179/GP1111 (PF-SZ-IFX) compared with European reference infliximab (Remicade®; ref-IFX) in patients with moderate-to-severe, active rheumatoid arthritis after continued long-term use of PF-SZ-IFX, and in patients who were switched from ref-IFX to PF-SZ-IFX. Methods: REFLECTIONS B537-02 was a double-blind, active-controlled, multinational study in which patients (N=650) were initially randomised to PF-SZ-IFX or ref-IFX for 30 weeks (treatment period [TP] 1). During weeks 30-54 (TP2), the PF-SZ-IFX group (n=280) continued treatment with PF-SZ-IFX (PF-SZ-IFX/PF-SZ-IFX) and patients in the ref-IFX group (n=286) were rerandomised (1:1) to continue ref-IFX (ref-IFX/ref-IFX) (n=143) or switch to PF-SZ-IFX (ref-IFX/PF-SZ-IFX) (n=143) for a further 24 weeks. Efficacy, safety, immunogenicity and pharmacokinetics were evaluated. Results: During TP2, patients in all three treatment groups continued to maintain comparable treatment response. At week 54, the American College of Rheumatology (ACR20) response rates were 71.1% (PF-SZ-IFX/PF-SZ-IFX), 64.3% (ref-IFX/ref-IFX) and 70.6% (ref-IFX/PF-SZ-IFX). Observations for other endpoints, including ACR50/70, Disease Activity Score in 28 Joints Based on High-Sensitivity C Reactive Protein(DAS28-CRP) remission, and mean change in DAS28-CRP and Health Assessment Questionnaire-Disability Index, were also comparable. Treatment-emergent adverse events were reported in 36.8% (PF-SZ-IFX/PF-SZ-IFX), 33.6% (ref-IFX/ref-IFX) and 37.8% (ref-IFX/PF-SZ-IFX) of patients; there were no clinically meaningful differences in the safety profiles between groups. The percentage of patients who were antidrug antibody-positive was generally stable through the treatment period and comparable overall between the PF-SZ-IFX/PF-SZ-IFX (52.1%; neutralising: 80.8%), ref-IFX/ref-IFX (60.1%; neutralising: 84.9%) and ref-IFX/PF-SZ-IFX (58.0%; neutralising 78.3%) groups. Conclusions: The similar efficacy, safety and immunogenicity of PF-SZ-IFX compared with ref-IFX were maintained for up to 54 weeks and were not affected by blinded treatment switch from ref-IFX to PF-SZ-IFX at week 30. Trial registration number: NCT02222493.