Biosimilar Drugs for RA Studied in Multiple Trials

Etanercept Biosimilars

A number of Phase 3 trials are ongoing for etanercept biosimilars.¹ One evaluation identified three trials in rheumatoid arthritis (RA) patients and one in psoriasis patients. The psoriatic arthritis trial evaluated PASI as a primary endpoint and the following secondary endpoints: PASI50, PASI75, PASI90, PASI score, laboratory values, ECG, adverse events (AEs), injection site reactions and immunogenicity. The RA trials are evaluating ACR20 as the primary endpoint. Secondary endpoints include ACR50, ACR70, DAS28, AEs, serious AEs, safety and immunogenicity.

Sarilumab (REGN88/SAR153191), an investigational fully human monoclonal antibody against the interleukin 6 receptor (IL-6R), met co-primary efficacy endpoints in a Phase 3, placebo-controlled clinical trial in RA patients.² The study, known as SARIL-RA-TARGET, evaluated safety and efficacy of two subcutaneous (SubQ) doses of sarilumab compared with placebo. Sarilumab was added to non-biologic disease-modifying antirheumatic drug (DMARD) therapy in RA patients who were intolerant to or had inadequate responders for tumor necrosis factor alpha inhibitors (n = 546). Patients received sarilumab 150 mg, sarilumab 200 mg or placebo injection every other week (Q2W).

ACR20 improvement was 61% in the sarilumab 200 mg Q2W dosed group, compared with 56% improvement in the sarilumab 150 mg group and 34% improvement in placebo-treated patients. Greater improvement in physical function was also noted by the change from baseline in the Health Assessment Questionnaire-Disability Index at Week 12. Sarilumab blocks IL-6 binding, subsequently interrupting cytokine-mediated inflammatory signaling. Adverse effects reported in the SARIL-RA-TARGET study included infections and injection site reactions. Neutrophil count reduction was the only laboratory abnormality noted in 0.6–1% of sarilumab-treated patients and 1% of placebo-treated patients. Serious infections were uncommon, and no unexpected safety findings were seen.

Methotrexate-induced pulmonary toxicity usually occurs within one year of beginning treatment.

Two additional Phase 3 studies have shown sarilumab meeting its primary endpoints. These studies include a total of 419 patients.² These studies are named SARIL-RA-EASY and SARIL-RA-ASCERTAIN.

Antirheumatic Drugs May Be Linked to Pulmonary Toxicity

At the ACR’s recent State-of-the-Art Clinical Symposium held in Chicago in May, Kristin Highland, MD, a critical care/pulmonologist and rheumatologist, reported on antirheumatic agents and their pulmonary toxicity, using data from Pneumotox Online, a website and mobile application used to assist in the diagnosis of drug-induced respiratory disease.^3,4

Of note, Dr. Highland singled out methotrexate (MTX) as an agent known for causing pulmonary toxicity. Potential risk factors for developing MTX-induced pulmonary toxicity include existing lung disease, diabetes, age, renal disease and prior use of DMARDs. Common presentations of this toxicity include dyspnea, non-productive cough and fever. MTX-induced pulmonary toxicity usually occurs within one year of beginning treatment. Chest radiographs show diffuse interstitial infiltrates and patchy infiltrates. A restrictive ventilatory defect is also usually seen.⁵