Anti-Drug Antibody Incidence Comparison of Therapeutic Proteins Administered Via Subcutaneous vs. Intravenous Route.

Subcutaneous (SC) administration of therapeutic proteins is perceived to pose higher risk of immunogenicity when compared with intravenous (IV) route of administration (RoA). However, systematic evaluations of clinical data to support this claim are lacking. This meta-analysis was conducted to compare the immunogenicity of the same therapeutic protein by IV and SC RoA. Anti-drug antibody (ADA) data and controlling variables for 7 therapeutic proteins administered by both IV and SC routes across 48 treatment groups were analyzed. RoA was the primary independent variable of interest while therapeutic protein, patient population, adjusted dose, and number of ADA samples were controlling variables. Analysis of variance was used to compare the ADA incidence between IV and SC RoA, while accounting for controlling variables and potential interactions. Subsequently, 10 additional therapeutic proteins with ADA data published for both IV and SC administration were added to the above 7 therapeutic proteins and were evaluated for ADA incidence. RoA had no statistically significant effect on ADA incidence for the initial dataset of 7 therapeutic proteins (p = 0.55). The only variable with a significant effect on ADA incidence was the therapeutic protein. None of the other controlling variables, including their interactions with RoA, was significant. When all data from the 17 therapeutic proteins were pooled, there was no statistically significant effect of RoA on ADA incidence (p = 0.81). In conclusion, there is no significant difference in ADA incidence between the IV and SC RoA, based on analysis of clinical ADA data from 17 therapeutic proteins.

Extension Study of PF-05280586, a Potential Rituximab Biosimilar, Versus Rituximab in Subjects With Active Rheumatoid Arthritis.

OBJECTIVE: This extension study provided continued treatment to subjects with active rheumatoid arthritis who had participated for ≥16 weeks in a pharmacokinetic similarity study of PF-05280586 (potential rituximab biosimilar). Objectives were to evaluate overall pharmacokinetics, pharmacodynamics, immunogenicity, safety, and tolerability of PF-05280586 after transition from rituximab reference products to PF-05280586, and follow-up of biomarker and efficacy assessments. METHODS: Subjects were offered ≤3 additional courses of treatment of PF-05280586, with or without a single transition from rituximab in Europe (rituximab-EU; MabThera) or the US (rituximab-US; Rituxan) to PF-05280586. Each course comprised 2 intravenous infusions (1,000 mg on days 1 and 15, separated by 24 weeks [± 8 weeks]). RESULTS: Of 220 subjects in the parent study, 185 were randomized and included in this study. There were no notable differences in drug concentrations between groups or across courses, with little variation in depletion of CD19+ B cells between groups, and no apparent relationship between infusion-related reactions and antidrug antibodies with or without single transition from rituximab reference products to PF-05280586. Long-term safety and tolerability of PF-05280586 was acceptable in all groups for up to 96 weeks, with a low incidence of treatment-emergent adverse events independent of single drug transition. The percentage of subjects with a low disease activity score and disease activity score remission was similar across groups for all time points, and responses were sustained until end of study. CONCLUSION: This study demonstrated acceptable safety, tolerability, and immunogenicity, with or without single transition from rituximab reference products to PF-05280586, without increased immunogenicity on single transition.

Modified-release sildenafil reduces Raynaud's phenomenon attack frequency in limited cutaneous systemic sclerosis.

OBJECTIVE: To examine the effect of sildenafil in patients with Raynaud's phenomenon (RP) secondary to limited cutaneous systemic sclerosis (lcSSc). METHODS: In this double-blind, placebo-controlled study, 57 patients with RP secondary to lcSSc were randomized to receive modified-release sildenafil 100 mg once daily for 3 days followed by modified-release sildenafil 200 mg once daily for 25 days or placebo. The primary assessment was the percentage change in the number of RP attacks per week in the per-protocol population. Secondary end points included Raynaud's Condition Score, duration of attacks, RP pain score, endothelial dysfunction assessed by a peripheral arterial tonometric (PAT) device, and serum biomarker levels. RESULTS: The mean percentage reduction from baseline to day 28 in attacks per week was greater for modified-release sildenafil than for placebo (-44.0% versus -18.1%, P = 0.034); the mean number of attacks per week improved from 25.0 at baseline to 19.3 after placebo treatment and from 30.5 to 18.7 after modified-release sildenafil treatment (P = 0.244). Decreases from baseline in Raynaud's Condition Score, duration of attacks, and RP pain score were not significantly different between groups. Mean values and changes from baseline in PAT responses and serum biomarker levels were similar between groups. The most frequent adverse events were headache and dyspepsia; the majority of adverse events were mild or moderate. CONCLUSION: Our findings indicate that modified-release sildenafil reduced attack frequency in patients with RP secondary to lcSSc and was well tolerated. Modified-release sildenafil may be a treatment option in this patient population.