Patient satisfaction following transition from the original to the new formulation of subcutaneous interferon beta-1a in relapsing multiple sclerosis: a randomized, two-arm, open-label, Phase IIIb study

Subcutaneous Interferon-β1a Does Not Increase the Risk of Stroke in Patients with Multiple Sclerosis: Analysis of Pooled Clinical Trials and Post-Marketing Surveillance

INTRODUCTION

Previous studies suggest that multiple sclerosis (MS) patients have a greater stroke risk than the general population but there is limited evidence of stroke risk in patients receiving disease-modifying treatment. We assessed stroke risk in MS patients treated with subcutaneous interferon-β1a (sc IFN-β1a) using pooled data from clinical trials and post-marketing surveillance.

METHODS

Seventeen phase II-IV Merck KGaA-sponsored trials of sc IFN-β1a were assessed to estimate the stroke incidence rate (IR) and IR ratio (IRR) per 100 patient-years (PY), and associated 95% confidence intervals (CI). The association of treatment duration with stroke was assessed through a Cox model. IR, IRR, and hazard ratio (HR) were adjusted by age, sex, presence of any comorbidity, and MS duration. Individual case safety reports were retrieved from the Global Patient Safety Database. The reporting rates of stroke were calculated and classified as medically confirmed or non-medically confirmed according to the source of each report.

RESULTS

In 17 clinical trials, 4412 patients were treated with sc IFN-β1a for a total of 10,622 PY and 1055 patients with placebo for 2005 PY. The IR/100 PY (95% CI) of stroke was 0.025 (0.004, 0.150) in sc IFN-β1a patients and 0.051 (0.008, 0.349) in placebo patients. The IRR for sc IFN-β1a vs placebo was 0.486 (0.238, 0.995) and the HR was 0.496 (0.235, 1.043) for time to stroke-related event for sc IFN-β1a treatment at any dose compared with placebo. Among sc IFN-β1a patients, the IRR in those treated for < 2 years was 0.602 (0.159, 2.277) and for ≥ 2 years 0.469 (0.196, 1.124). Analysis of the safety database showed that the overall reporting rate for stroke was 13.286/10,000 PY.

CONCLUSION

Safety data from both clinical trial and post-marketing settings indicate that treatment with sc IFN-β1a does not increase stroke risk in patients with MS.

FUNDING

Merck KGaA, Darmstadt, Germany.

Subcutaneous IFN-β1a to treat relapsing-remitting multiple sclerosis

Multiple sclerosis (MS) is the main nontraumatic cause of handicap in young adults. Immunomodulators and treatments limiting lymphocyte migration have been proven efficient to treat relapsing-remitting MS. Subcutaneous IFN-β1a improve relapse rate and MRI parameters in a series of double-blind, placebo-controlled trials in relapsing-remitting MS patients. Similar results, and with a greater extent, were obtained when treating patients with a first demyelinating event suggestive of MS. Except for the rare liver toxicity, the drug is well tolerated and has no severe adverse reaction. When compared with intramuscular IFN-β1a, both relapse rate and MRI parameters were modulated in favor of the subcutaneous administration. Although the effect of subcutaneous IFN-β1a on disability progression is limited, the good tolerance profile together with the efficiency of the drug explain why this treatment, as well as the other interferons and glatiramer acetate, is a first-line therapy for relapsing-remitting MS.

Rebif(®) Quality of Life (RebiQoL): A randomized, multicenter, Phase IIIb study evaluating quality-of-life measures in patients receiving the serum-free formulation of subcutaneous interferon beta-1a for the treatment of relapsing forms of multiple sclerosis

BACKGROUND

In clinical studies, treatment with subcutaneous interferon beta-1a (IFNβ-1a) has been shown to reduce relapse rates and slow the progression of physical disability in patients with relapsing forms of multiple sclerosis (MS). A formulation of subcutaneous IFNβ-1a has been developed that is free of fetal bovine serum and human serum albumin.

OBJECTIVE

To evaluate (a) the impact on quality of life (QoL) and treatment satisfaction of transitioning from the original formulation of subcutaneous IFNβ-1a to the serum-free formulation in patients with relapsing forms of MS; and (b) the impact of dose titration versus non-titration during the transition on tolerability and patterns of analgesic use. QoL was measured by the Multiple Sclerosis Treatment Concerns Questionnaire Global Side Effects (GSE) score.

METHODS

Patients who had received the original formulation of IFNβ-1a subcutaneously for ≥24 weeks were randomized to receive the serum-free formulation of IFNβ-1a 44μg subcutaneously three times weekly for 12 weeks, with or without a dose titration over a 4-week period. After week 12, patients continued to receive serum-free subcutaneous IFNβ-1a during a safety extension phase until they completed between 84 and 112 weeks of treatment. The primary endpoint was the percentage change from baseline to week 12 in GSE score in all patients.

RESULTS

A total of 232 patients were randomized (titrated n=113; non-titrated n=119). The mean percent change (improvement) from baseline to week 12 in the GSE score was 5.0% (p<0.001 for mean change in GSE score from baseline); this change was similar between titrated and non-titrated patients and met criteria for non-inferiority to the original formulation. Adverse event (AE) incidence and use of analgesics for the treatment of flu-like symptoms (FLS) were less common in the titrated group. Few patients (<2%) discontinued due to AEs during weeks 0 to 12.

CONCLUSION

Patients with relapsing forms of MS who transitioned from original-formulation subcutaneous IFNβ-1a to serum-free subcutaneous IFNβ-1a had overall improved QoL scores at 12 weeks of treatment. Titration during the transition resulted in a lower requirement for analgesic treatment of FLS and fewer AEs.

Subcutaneous recombinant interferon-β-1a (Rebif®): a review of its use in the treatment of relapsing multiple sclerosis

Subcutaneous recombinant interferon-β-1a (SC IFNβ-1a) [Rebif®] is indicated as monotherapy for the prevention of relapses and progression of physical disability in patients with relapsing multiple sclerosis (MS). This article reviews the efficacy and tolerability of SC IFNβ-1a in this indication, with further discussion of its pharmacological properties and pertinent pharmacoeconomic studies. SC IFNβ-1a efficacy and tolerability were evaluated in randomized, double-blind, multinational trials in patients with relapsing-remitting MS (RRMS). Its efficacy was demonstrated in the 2-year PRISMS trial, as SC IFNβ-1a 22 or 44 μg three times weekly (tiw) significantly reduced relapse rates, with an ≈30% relative risk reduction compared with placebo. SC IFNβ-1a was also associated with significantly delayed progression of disability, and lower disease activity according to MRI, relative to placebo. In the 24-week EVIDENCE trial, a significantly higher proportion of SC IFNβ-1a 44 μg tiw than intramuscular IFNβ-1a (Avonex®) 30 μg once weekly recipients remained relapse free. A serum-free formulation of SC IFNβ-1a 44 μg tiw was more efficacious than placebo in preventing the development of brain lesions in the 16-week IMPROVE trial. In the 96-week REGARD trial, the efficacy of SC IFNβ-1a 44 μg tiw was not significantly different to that of glatiramer acetate for clinical endpoints, although it was associated with reduced development of brain lesions compared with glatiramer acetate, according to some MRI endpoints. In the 36-month CAMMS223 trial, alemtuzumab led to significantly lower relapse rates and risk of developing sustained disability than SC IFNβ-1a 44 μg tiw, and was generally more efficacious according to other clinical and MRI endpoints. Across trials, influenza-like symptoms, injection-site reactions, haematological disturbances and hepatic enzyme abnormalities were the most common treatment-emergent adverse events occurring with SC IFNβ-1a. In the PRISMS trial, SC IFNβ-1a 22 and 44 μg tiw recipients had more injection-site reactions than placebo recipients and, at the higher dosage, haematological disturbances and increases in ALT levels were also significantly more frequent than with placebo. Pooled data from clinical trials and postmarketing surveillance indicate that haematological and hepatic adverse events are generally asymptomatic and rarely result in treatment discontinuation. Nevertheless, some cases of serious hepatic complications have been reported. In cost-utility studies, first-line therapies for RRMS, including SC IFNβ-1a, all exceeded commonly accepted US thresholds for incremental cost per quality-adjusted life-years gained relative to symptomatic treatment. However, because of patient need and the difficulty in adequately assessing cost utility in a gradually progressive disease, these agents have been made available to many patients worldwide through special access programmes. Overall, SC IFNβ-1a has a favourable risk-benefit ratio and is a valuable first-line treatment option for patients with relapsing MS.