Comparative tolerance of IFN beta-1a regimens in patients with relapsing multiple sclerosis

Clinical effectiveness and cost-effectiveness of beta-interferon and glatiramer acetate for treating multiple sclerosis: systematic review and economic evaluation

BACKGROUND

At the time of publication of the most recent National Institute for Health and Care Excellence (NICE) guidance [technology appraisal (TA) 32] in 2002 on beta-interferon (IFN-β) and glatiramer acetate (GA) for multiple sclerosis, there was insufficient evidence of their clinical effectiveness and cost-effectiveness.

OBJECTIVES

To undertake (1) systematic reviews of the clinical effectiveness and cost-effectiveness of IFN-β and GA in relapsing-remitting multiple sclerosis (RRMS), secondary progressive multiple sclerosis (SPMS) and clinically isolated syndrome (CIS) compared with best supportive care (BSC) and each other, investigating annualised relapse rate (ARR) and time to disability progression confirmed at 3 months and 6 months and (2) cost-effectiveness assessments of disease-modifying therapies (DMTs) for CIS and RRMS compared with BSC and each other.

REVIEW METHODS

Searches were undertaken in January and February 2016 in databases including The Cochrane Library, MEDLINE and the Science Citation Index. We limited some database searches to specific start dates based on previous, relevant systematic reviews. Two reviewers screened titles and abstracts with recourse to a third when needed. The Cochrane tool and the Consolidated Health Economic Evaluation Reporting Standards (CHEERS) and Philips checklists were used for appraisal. Narrative synthesis and, when possible, random-effects meta-analysis and network meta-analysis (NMA) were performed. Cost-effectiveness analysis used published literature, findings from the Department of Health's risk-sharing scheme (RSS) and expert opinion. A de novo economic model was built for CIS. The base case used updated RSS data, a NHS and Personal Social Services perspective, a 50-year time horizon, 2014/15 prices and a discount rate of 3.5%. Outcomes are reported as incremental cost-effectiveness ratios (ICERs). We undertook probabilistic sensitivity analysis.

RESULTS

In total, 6420 publications were identified, of which 63 relating to 35 randomised controlled trials (RCTs) were included. In total, 86% had a high risk of bias. There was very little difference between drugs in reducing moderate or severe relapse rates in RRMS. All were beneficial compared with BSC, giving a pooled rate ratio of 0.65 [95% confidence interval (CI) 0.56 to 0.76] for ARR and a hazard ratio of 0.70 (95% CI, 0.55 to 0.87) for time to disability progression confirmed at 3 months. NMA suggested that 20 mg of GA given subcutaneously had the highest probability of being the best at reducing ARR. Three separate cost-effectiveness searches identified > 2500 publications, with 26 included studies informing the narrative synthesis and model inputs. In the base case using a modified RSS the mean incremental cost was £31,900 for pooled DMTs compared with BSC and the mean incremental quality-adjusted life-years (QALYs) were 0.943, giving an ICER of £33,800 per QALY gained for people with RRMS. In probabilistic sensitivity analysis the ICER was £34,000 per QALY gained. In sensitivity analysis, using the assessment group inputs gave an ICER of £12,800 per QALY gained for pooled DMTs compared with BSC. Pegylated IFN-β-1 (125 µg) was the most cost-effective option of the individual DMTs compared with BSC (ICER £7000 per QALY gained); GA (20 mg) was the most cost-effective treatment for CIS (ICER £16,500 per QALY gained).

LIMITATIONS

Although we built a de novo model for CIS that incorporated evidence from our systematic review of clinical effectiveness, our findings relied on a population diagnosed with CIS before implementation of the revised 2010 McDonald criteria.

CONCLUSIONS

DMTs were clinically effective for RRMS and CIS but cost-effective only for CIS. Both RCT evidence and RSS data are at high risk of bias. Research priorities include comparative studies with longer follow-up and systematic review and meta-synthesis of qualitative studies.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42016043278.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.

Cutaneous adverse events associated with disease-modifying treatment in multiple sclerosis: a systematic review

Glatiramer acetate and interferon-beta are approved first-line disease-modifying treatments (DMTs) for multiple sclerosis (MS). DMTs can be associated with cutaneous adverse events, which may influence treatment adherence and patient quality of life. In this systematic review, we aimed to provide an overview of the clinical spectrum and the incidence of skin reactions associated with DMTs. A systematic literature search was performed up to May 2011 in Medline, Embase, and Cochrane databases without applying restrictions in study design, language, or publishing date. Eligible for inclusion were articles describing any skin reaction related to DMTs in MS patients. Selection of articles and data extraction were performed by two authors independently. One hundred and six articles were included, of which 41 (39%) were randomized controlled trials or cohort studies reporting incidences of mainly local injection-site reactions. A large number of patients had experienced some form of localized injection-site reaction: up to 90% for those using subcutaneous formulations and up to 33% for those using an intramuscular formulation. Sixty-five case-reports involving 106 MS patients described a wide spectrum of cutaneous adverse events, the most frequently reported being lipoatrophy, cutaneous necrosis and ulcers, and various immune-mediated inflammatory skin diseases. DMTs for MS are frequently associated with local injection-site reactions and a wide spectrum of generalized cutaneous adverse events, in particular, the subcutaneous formulations. Although some of the skin reactions may be severe and persistent, most of them are mild and do not require cessation of DMT.

Comparison of two dosing frequencies of subcutaneous interferon beta-1a in patients with a first clinical demyelinating event suggestive of multiple sclerosis (REFLEX): a phase 3 randomised controlled trial

BACKGROUND

In patients presenting with a first clinical demyelinating event that is suggestive of multiple sclerosis (MS), treatment with interferon beta can delay the occurrence of further attacks and the onset of MS. We investigated the effects of two dosing frequencies of subcutaneous interferon beta-1a in patients with a first clinical demyelinating event.

METHODS

We undertook a multicentre phase 3 study (REbif FLEXible dosing in early MS [REFLEX]) that included patients (aged 18-50 years) with a single clinical event suggestive of MS, and at least two clinically silent T2 lesions on brain MRI. Participants were randomly assigned in a 1:1:1 ratio by use of a centralised interactive voice response system to receive the serum-free formulation of subcutaneous interferon beta-1a 44 μg three times a week or once a week (plus placebo twice a week for masking), or placebo three times a week for up to 24 months. Patients and physicians were masked to group allocation. The primary endpoint was time to a diagnosis of MS as defined by the 2005 McDonald criteria and the main secondary endpoint was time to clinically definite MS (CDMS) as defined by the Poser criteria. Analysis was by intention to treat. The study is registered with ClinicalTrials.gov, number NCT00404352.

FINDINGS

517 patients were randomly assigned (171 to subcutaneous interferon beta-1a three times a week, 175 to subcutaneous interferon beta-1a once a week, and 171 to placebo) and 515 were treated. The 2-year cumulative probability of McDonald MS was significantly lower in patients treated with subcutaneous interferon beta-1a (three times a week 62·5%, p<0·0001, hazard ratio [HR] 0·49 [95% CI 0·38-0·64]; once a week 75·5%, p=0·008, HR 0·69 [0·54-0·87]) versus placebo (85·8%). 2-year rates of conversion to CDMS were lower for both interferon beta-1a dosing regimens (three times a week 20·6%, p=0·0004, HR 0·48 [0·31-0·73]; once a week 21·6%, p=0·0023, HR 0·53 [0·35-0·79]) than for placebo (37·5%). Adverse events were within the established profile for subcutaneous interferon beta-1a.

INTERPRETATION

Both regimens of subcutaneous interferon beta-1a delayed clinical relapses and subclinical disease activity. The potential differences between the regimens warrant longer-term study.

FUNDING

Merck Serono SA, Geneva, Switzerland.

[Discontinuation and long-term adherence to beta interferon therapy in patients with multiple sclerosis]

OBJECTIVE

To determine discontinuation rate and degree of adherence to first-line treatment with interferon-beta (INFβ) in patients with multiple sclerosis (MS), identifying causes and associated factors.

MATERIAL AND METHOD

A retrospective observational study that included patients with MS treated with INFβ during 2001. The patients were followed-up from the beginning of treatment until the end of 2006. The data sources used were a computer database compiled in the outpatients' area, medical records and application protocols for beginning and monitoring treatment for MS. Patient characteristics at baseline, treatment and continuity were included in the information collected.

RESULTS

The study included 131 patients. Mean follow-up was 74 ± 26 years. 641% of the patients were treated with only one drug during the study. At 2 years follow-up 99% of patients had discontinued INFβ therapy and at 5 years 412% had done so. Men, patients with relapsing-remitting MS and those treated with INFβ1a i.m. continued treatment for a longer period, but this was statistically significant only in patients with 10 years or less of disease progression at the beginning of therapy. Main causes of discontinuation were lack of efficacy (388%) and adverse effects (328%). Compliant patients presented lower discontinuation rates (558% vs. 75%).

CONCLUSIONS

treatment of MS patients with IFNβ is discontinued mainly due to lack of efficacy and adverse effects. Greater understanding of patients' views can help to identify those at greatest risk of lack of adherence, thereby helping to improve treatment.

Role of differential expression of interferon receptor isoforms on the response of multiple sclerosis patients to therapy with interferon beta

The cytokine interferon (IFN)-β is successfully used in the treatment of multiple sclerosis. However, some patients fail to respond to therapy, probably due to different biological patterns that are of importance in influencing clinical response. A common mechanism involved in the modulation of responsiveness to cytokine is represented by regulation of their receptor expression through autocrine-ligand-mediated loops. Mechanistically, IFN-β exerts its biological effects through interaction with the IFN-α/-β-receptor (IFNAR), which then activates several transcription factors. IFNAR is composed of 2 chains, IFNAR-1 and IFNAR-2, which associate with IFN-β to form a ternary complex. The major ligand-binding subunit is IFNAR-2 and it exists in 3 mRNA splice variants, resulting in 2 transmembrane (IFNAR-2b and IFNAR-2c) isoforms and a soluble (IFNAR-2a) one. On the contrary, from normal cells only one IFNAR-1 isoform, with transcriptional capacity, was identified. In the past decades, considerable information has accumulated pertaining to the downregulation of the IFNAR complex in IFN-treated patients, but only a few studies have investigated the molecular events involved in this phenomenon. The intent of the present review is to place this receptor downregulation in the context of IFN-β therapy and of its clinical and biological outcomes in IFN-β-treated patients.

Clinical effects and tolerability of high-dose, high-frequency recombinant interferon beta-1a in patients with multiple sclerosis: maximizing therapy through long-term adherence

IMPORTANCE OF THE FIELD

High-dose, high-frequency IFN beta-1a in multiple sclerosis (MS) can prevent lesion formation, decrease the frequency/severity of relapses and delay progression of disability, with a proven safety profile. Rates of non-adherence are high. There are drugs under investigation that may have greater efficacy and different safety profiles from existing therapies.

AREAS COVERED IN THIS REVIEW

Evidence supporting the efficacy of IFN beta-1a, factors contributing to non-adherence, and strategies to combat non-adherence. It is hoped that these strategies, coupled with future advances in pharmacogenetics, might lead to better outcomes. The PubMed database was searched using the terms "multiple sclerosis" and "interferon beta-1a", for papers published between 1998 and 2010. Relevant manuscripts and pivotal papers from clinical trials were cited. Searches of abstracts from congresses were also performed to obtain recent findings.

WHAT THE READER WILL GAIN

An overview of early pivotal trials, comparative studies with other treatments, and recent studies assessing the development of this therapy.

TAKE HOME MESSAGE

Long-term treatment with IFN beta-1a has benefits in MS and a good safety profile. Although adherence outside of clinical trials can be poor, injection devices, better tolerated drug formulations and education regarding treatment expectations are some of the strategies employed to help patients to adhere to treatment in the hope of improving outcomes.

Assessing cost-effectiveness in the management of multiple sclerosis

Multiple sclerosis (MS) is one of the most common causes of neurological disability in young and middle-aged adults, with current prevalence rates estimated to be 30 per 100,000 populations. Women are approximately twice as susceptible as males, but males are more likely to have progressive disease. The onset of the disease normally occurs between 20 and 40 years of age, with a peak incidence during the late twenties and early thirties, resulting in many years of disability for a large proportion of patients, many of whom require wheelchairs and some nursing home or hospital care. The aim of this study is to update a previous review which considered the cost-effectiveness of disease-modifying drugs (DMDs), such as interferons and glatiramer acetate, with more up to date therapies, such as mitaxantrone hydrochloride and natalizumab in the treatment of MS. The development and availability of new agents has been accompanied by an increased optimism that treatment regimens for MS would be more effective; that the number, severity and duration of relapses would diminish; that disease progression would be delayed; and that disability accumulation would be reduced. However, doubts have been expressed about the effectiveness of these treatments, which has only served to compound the problems associated with endeavors to estimate the relative cost-effectiveness of such interventions.

Improving compliance with interferon-beta therapy in patients with multiple sclerosis

Multiple sclerosis (MS) is an inflammatory demyelinating disease affecting young adults (with a peak of onset between the ages of 20 and 40 years). In 80-90% of cases, it is characterized by an early relapsing-remitting (RR) inflammatory phase, followed by a secondary progressive course in which disability progressively accumulates. Interferon-beta (IFNbeta) therapies represent the first-line treatment of RRMS. There are three IFNbeta formulations currently licensed for RRMS. Two are formulations of INFbeta-1a, one administered at a dosage of 30 mug intramuscularly weekly (Avonex(R)) and the other administered at a dosage of 22 or 44 microg subcutaneously (SC) three times a week (Rebif(R) 22 and 44). The third is a formulation of IFNbeta-1b, administered at a dosage of 250 microg SC every other day (Betaseron(R)). These treatments reduce the frequency of acute relapses and, to a lesser extent, disability progression. However, when starting an IFNbeta therapy, a treatment discontinuation rate ranging from 14% to 44% has to be expected. In a sizable proportion of patients, treatment suspension is caused by the occurrence of adverse effects (most commonly a flu-like syndrome and injection site reactions) and/or poor compliance. Individualized patient education and support are critical to improve adherence to therapy in the long term. Approaches aimed at reducing the proportion of subjects interrupting IFNbeta encompass both pharmacological and non-pharmacological interventions, and may involve several professional figures, such as the neurologist, the psychologist, the pharmacist, the physical and speech therapist, and the nurse. Recently, the development of new IFNbeta formulations, with reduced immunogenic potential, has offered an additional approach to improving patient adherence. Biferonex(R) is a pH neutral and human serum albumin-free IFNbeta-1a. A phase III, 2-year study of the product involving patients with RRMS has been conducted, but the results were not considered conclusive enough to allow approval in Europe. Rebif(R) New Formulation (RNF) is a formulation of INFbeta-1a that is not produced using fetal bovine serum and that does not have human serum albumin as an excipient. The formulation has been approved in Europe and an application for approval has been filed in the US. On the basis of the final analysis of a phase III trial, RNF showed higher tolerability, particularly in terms of injection site reactions, compared with the older formulation. Further studies assessing its usefulness as an alternative therapy for patients who are intolerant of other IFNbeta formulations are required.

High-dose, high-frequency recombinant interferon beta-1a in the treatment of multiple sclerosis

BACKGROUND

There is at present no cure for multiple sclerosis (MS), and existing therapies are designed primarily to prevent lesion formation, decrease the rate and severity of relapses and delay the resulting disability by reducing levels of inflammation.

OBJECTIVE

The aim of this review was to assess the treatment of relapsing MS with particular focus on subcutaneous (s.c.) interferon (IFN) beta-1a.

METHOD

The literature on IFN beta-1a therapy of MS was reviewed based on a PubMed search (English-language publications from 1990) including its pharmacodynamics and pharmacokinetics, clinical efficacy in relapsing MS as shown in placebo-controlled studies and in comparative trials, efficacy in secondary progressive MS, safety and tolerability, and the impact of neutralizing antibodies.

CONCLUSION

The literature suggests that high-dose, high-frequency s.c. IFN beta-1a offers an effective option for treating patients with relapsing MS, with proven long-term safety and tolerability, and has a favourable benefit-to-risk ratio compared with other forms of IFN beta.

Chronic myeloid leukaemia in two multiple sclerosis patients on interferon beta-1a

Haematological problems are commonly associated with use of beta-interferon in multiple sclerosis (MS) patients. However these problems are usually benign and are reversible when the drug is stopped. We describe two patients, with the diagnosis of MS, who developed leucocytosis. Cytogenetic studies showed the presence of the Philadelphia chromosome in all the cells analysed, confirming the diagnosis of chronic myeloid leukaemia (CML). The first patient currently on imatimib mesylate and interferon beta-1a is asymptomatic. For the second patient, interferon beta-1a was withdrawn after suspicion of CML.

A review of disease-modifying therapies for MS: maximizing adherence and minimizing adverse events

BACKGROUND

In a chronic disabling disorder such as multiple sclerosis (MS), adherence to treatment is of critical importance in maximizing benefits of therapy over the long term. Adverse events (AEs) are often cited by patients who discontinue therapy.

METHODS

Databases including Medline, CINAHL, and International Pharmaceutical Abstracts were searched for literature pertaining to adherence and AEs in MS published between January 1970 and August 2008. Clinical studies and case reports of AEs were included, as were papers that outlined factors that influence adherence. An advisory board with extensive experience in managing patients with MS developed guidelines to assist healthcare providers in maximizing adherence to disease-modifying therapy.

DISCUSSION

Internally based factors such as self-image, and externally based factors such as AEs, may influence patients' willingness and ability to adhere to therapy. Management of AEs associated with disease-modifying therapies and other therapies is reviewed, including intramuscular and subcutaneous interferon beta (IFNbeta)-1a, IFNbeta-1b, glatiramer acetate, natalizumab, methylprednisolone, mitoxantrone, cyclophosphamide, methotrexate, azathioprine, and intravenous immunoglobulin.

CONCLUSIONS

Effective management of MS is an ongoing, dynamic process that can enhance patients' adherence to therapy. Healthcare practitioners may address factors influencing adherence among patients with MS by managing treatment expectations, maintaining good communication with the patient, and managing AEs of treatment. Although the guidelines proposed herein originate from a single advisory board, it seems clear that by addressing patient concerns, healthcare practitioners can work with patients to enhance their ability to continue to adhere to their therapies and thereby gain the benefits of their treatment over the long term.

Treating relapsing multiple sclerosis with subcutaneous versus intramuscular interferon-beta-1a: modelling the clinical and economic implications

The EVIDENCE trial concluded that administering high-dose/high-frequency subcutaneous (SC) interferon-beta-1a (IFNb1a) was more effective in preventing relapses among patients with relapsing multiple sclerosis (MS) than low-dose weekly intramuscular (IM) IFNb1a after 64 weeks. This analysis utilized discrete-event simulation (DES) to model the potential longer-term clinical and economic implications of this trial. A DES predicting the course of relapsing MS and incorporating the effect of IFNb1a therapy was developed. The model began by randomly reading in actual patient data from the trial to create 1000 patients. Each simulated patient was replicated - one was assigned to receive SC IFNb1a three times a week and the other to receive IM IFNb1a once a week. During the simulation, patients may (i) experience relapses, with associated short- and long-term impacts on costs and disability; (ii) develop new T2 lesions detected by a magnetic resonance imaging scan; (iii) discontinue treatment because of adverse events or lack of response; (iv) advance to secondary progressive MS; or (v) die. Model inputs were mainly obtained from the EVIDENCE trial, but were taken from published literature if they could not be obtained from the trial. Direct medical costs ($US, year 2006 values) to the US payers were primarily obtained by updating a published cost analysis. Costs and benefits were discounted at 3% per annum. Extensive sensitivity analyses were conducted to test the robustness of the model results. Based on 100 replications of 1000 patient pairs over 4 years, SC IFNb1a was predicted to enable more patients to avoid relapse (216 vs 147). Total mean costs per patient (discounted) were $US79 890 with SC IFNb1a versus $US74 485 with IM administration, a net increase of $US5405 per patient. However, SC IFNb1a was estimated to prevent 0.50 relapses and save 23 relapse-free days per patient, yielding incremental cost-effectiveness ratios of $US10 755 per relapse prevented and $US232 per relapse-free day gained. Sensitivity analyses revealed that the result was most sensitive to the treatment efficacy, model time horizon and cost of IFNb1a treatment. Based on the results observed in the EVIDENCE trial, the model predicted that SC IFNb1a would yield greater health benefits over 4 years than IM IFNb1a, at a cost that would seem to be a reasonable trade-off.

Safety and tolerability in relapsing-remitting multiple sclerosis patients treated with high-dose subcutaneous interferon-beta by Rebiject autoinjection over a 1-year period: the CoSa study

OBJECTIVES

Approved multiple sclerosis (MS) treatments include subcutaneous and intramuscular interferon beta (IFN-beta) Patient satisfaction during long-term IFN-beta treatment is crucial. This study investigated the satisfaction of patients with relapsing-remitting MS treated with IFN-beta-1a (Rebif) by the autoinjection system, Rebiject.

MATERIALS AND METHODS

This prospective observational study recruited subjects with relapsing-remitting MS (n = 76) from 19 neurological centers in Italy who were eligible for subcutaneous IFN-beta-1a treatment either as a first immunomodulatory therapy or as a switch from other treatments. Patients received IFN-beta-1a 44 mug 3 times weekly via the Rebiject system. A questionnaire on the use of Rebiject and the most common adverse effects related to IFN-beta-1a administration was completed monthly under the supervision of trained nurses.

RESULTS

Satisfaction with treatment was reported by 80.2% of patients who received at least 1 dose. Advantages reported for the Rebiject system included its convenience (53% of all patients), ease of use (25%), reduced trauma and pain (11% and 6%, respectively), and reduced local skin reactions (5%). No significant changes from baseline were observed regarding the frequency or severity of local reactions.

CONCLUSIONS

During the 1-year observation of this small cohort, most patients considered the Rebiject system to be convenient, with a third of the patients feeling that the system was easier to use than conventional procedures. Rebiject was also associated with less pain and trauma in some patients. Use of Rebiject may facilitate IFN-beta-1a administration and may lead to an increase in compliance and adherence, thus increasing the effectiveness of treatment.

The Rebif new formulation story: it's not trials and error

The rapid evolution of the biopharmaceutical industry and the development of innovative technologies have provided an opportunity to improve recombinant interferon (IFN)-beta formulations. A number of strategies have been developed to improve the stability, tolerability and immunogenicity of IFNbeta formulations that are used in the long-term treatment of patients with multiple sclerosis (MS). This review focuses on the production of recombinant IFNs and discusses the development of one such biopharmaceutical, Rebif New Formulation (RNF).RNF was developed with the aim of further improving the tolerability and immunogenicity of Rebif, an approved IFNbeta-1a formulation administered subcutaneously three times per week (sc tiw). To this end, numerous candidate drug vehicles and formulations were developed. However, unlike other formulations of IFNbeta, the new candidate formulations in this case were free from all serum-derived components. Specifically, each RNF candidate was free from human serum albumin and produced without fetal bovine serum. The physicochemical stability, injection-site tolerability, pharmacokinetic profile and immunogenic potential of each candidate formulation were systematically tested. This involved initial screening of a large pool of formulations for promising candidates. Two candidate formulations were selected and subjected to further, extensive evaluation.Ex vivo T-cell assays were used to compare the immunogenicity of RNF candidates with that of the current (at the time of writing) approved formulation and an IFNbeta standard. A single RNF candidate induced less T-cell activation, in terms of proliferation and proinflammatory cytokine secretion, than the other two formulations. The results provided ex vivo evidence of the improved immunogenic potential of RNF. A murine model was used to compare the relative immunogenicity of RNF in vivo with two approved formulations of IFNbeta-1a. Mice treated with RNF developed neutralising antibodies more slowly and produced lower titres than mice treated with equivalent doses of the current IFNbeta-1a sc tiw formulation or another approved IFNbeta-1a formulation administered intramuscularly once per week (Avonex). RNF also demonstrated better local tolerability than the current IFNbeta-1a sc tiw formulation after single subcutaneous doses in healthy volunteers. One RNF candidate was superior to the others in all preclinical and phase I studies, and was chosen as the final RNF. This formulation is currently undergoing assessment in a 96-week, phase IIIb clinical trial in patients with MS. This single-arm, open-label, multicentre study will compare the immunogenicity and tolerability of RNF with historical data on the current formulation; results of a 48-week, interim analysis indicate that RNF has improved local tolerability and immunogenicity compared with the current formulation. It is anticipated that the benefits of RNF will translate into an improved long-term benefit-to-risk profile. Further assessment of RNF and other MS drugs is ongoing with the aim of enhancing the therapeutic options available for patients with MS.

Immunogenicity and tolerability of an investigational formulation of interferon-beta1a: 24- and 48-week interim analyses of a 2-year, single-arm, historically controlled, phase IIIb study in adults with multiple sclerosis

BACKGROUND

RNF (Rebif New Formulation, Merck Serono International S.A., Geneva, Switzerland), a formulation of interferon-beta1a (IFN-beta1a) without human- or animal-derived components, is currently under investigation. It was developed with the aim of maximizing the treatment benefit for patients with multiple sclerosis (MS) by improving injection tolerability and reducing the development of neutralizing antibodies (NAbs).

OBJECTIVE

This paper reports the results of planned 24- and 48-week interim analyses comparing immunogenicity and tolerability data from an ongoing study of RNF with historical-control data for the currently approved formulation of IFN-beta1a from the EVIDENCE (EVidence of Interferon Dose-response: European North American Comparative Efficacy) study.

METHODS

Patients in the 96-week, multicenter, singlearm, Phase IIIb RNF study received 44 microg/0.5 mL SC tiw; patients in the EVIDENCE study received an identical regimen of the currently approved formulation of IFN-beta1a. Criteria for inclusion in the RNF study were age between 18 and 60 years, an Expanded Disability Status Scale (EDSS) score <6.0, and a diagnosis of relapsing MS (McDonald criteria). Criteria for inclusion in the EVIDENCE study were age between 18 and 55 years, an EDSS score of 0 to 5.5, and a diagnosis of clinically definite relapsing-remitting MS (Poser criteria). Patients in both studies were treatment naive. Both studies used the same cytopathic-effect assay for NAbs to assess immunogenicity; patients who had NAb titers >or=20 neutralizing units (NU)/mL were considered NAb+. The primary end point was to compare the proportions of NAb+ patients in the RNF study and the historical data. Comparisons were descriptive and used exact 95% CIs. Safety analyses included 8 prespecified adverse events (AEs) of interest.

RESULTS

Baseline demographic characteristics were well balanced between the RNF (N = 260) and EVIDENCE (N = 339) studies, except that patients in the RNF study were slightly younger (median age, 34.0 vs 39.0 years, respectively), and a few had secondary progressive MS (n = 6) or progressive relapsing MS (n = 1). At week 48, 87.3% of patients in the RNF study remained on treatment. The incidence of the prespecified AEs of interest in the RNF and EVIDENCE studies was as follows: flu-like symptoms (70.8% and 48.1%, respectively), injection-site reactions (29.6% and 83.8%), hepatic disorders (13.1% and 16.8%), cytopenia (9.6% and 11.8%), depression and suicidal ideation (5.8% and 19.8%), skin rashes (5.4% and 12.1%), hypersensitivity reactions (5.4% and 3.2%), and thyroid disorders (2.3% and 5.0%). Overall, the majority (96.9%) of AEs in the RNF study were mild (69.5%) or moderate (27.5%) in severity. The proportions of patients in the RNF and EVIDENCE studies with NAbs at both 24 and 48 weeks were 2.5% (95% CI, 0.9-5.5) and 14.3% (95% CI, 10.7-18.6), respectively; the proportions with NAbs at week 48 only were 13.9% (95% CI, 9.9-18.7) and 24.4% (95% CI, 19.9-29.4). The proportions of NAb+ patients with high NAb titers (>1000 NU/mL) at week 48 were 11.1% in the RNF study and 19.5% in the EVIDENCE study.

CONCLUSIONS

The results of these interim analyses suggest that RNF had an improved overall tolerability and safety profile and a lower immunogenic potential compared with the approved IFN-beta1a formulation assessed in the EVIDENCE study. Two-year results from the RNF study are anticipated before the end of 2007.

Benefits of high-dose, high-frequency interferon beta-1a in relapsing-remitting multiple sclerosis are sustained to 16 months: final comparative results of the EVIDENCE trial

The EVIDENCE trial demonstrated that interferon (IFN) beta-1a, 44 mcg subcutaneously (sc) three times weekly (tiw) (Rebif), was significantly more effective than IFN beta-1a, 30 mcg intramuscularly (im) once weekly (qw) (Avonex), in reducing relapses and magnetic resonance imaging (MRI) activity in patients with relapsing-remitting multiple sclerosis at both 24 and 48 weeks of therapy. We now present final comparative data on these patients, showing that the superior efficacy of IFN beta-1a, 44mcg sc tiw, for relapse measures and MRI activity, compared with IFN beta-1a, 30mcg im qw, was sustained for at least 16 months. The development of antibodies to IFN was associated with reduced efficacy on MRI measures and fewer IFN-related adverse events, but did not have an impact on relapse outcomes.

Subcutaneous Recombinant Interferon-??-1a (Rebif??)

Subcutaneous recombinant interferon-beta-1a (Rebif) 22 or 44 microg three times weekly is a valuable option in the first-line treatment in patients with relapsing-remitting multiple sclerosis (RRMS). It has shown benefits on outcome measures related to relapses, progression of disability and magnetic resonance imaging (MRI) in clinical trials. A significant efficacy advantage for subcutaneous interferon-beta-1a three times weekly over intramuscular interferon-beta-1a 30 microg once weekly was shown at 24 and 48 weeks. The most common adverse events are generally mild and clinically manageable. Considering both direct and indirect comparative clinical trial data, an assessment suggests that subcutaneous interferon-beta-1a 44 microg three times weekly has the best benefit-to-risk values of the available disease-modifying drugs used to treat RRMS.

Importance of benefit-to-risk assessment for disease-modifying drugs used to treat MS

Interferon (IFN) beta has been shown to be an effective therapy in pivotal studies of multiple sclerosis (MS), with differences in outcomes based on dose and/or frequency of administration. Glatiramer acetate (GA) has also shown to have an effect on relapses and magnetic resonance imaging measures, but not on disability. All products are associated with adverse events, and utilisation of a specific therapy needs to consider benefit in relation to risk. Evidence-based medicine provides a means of assessing benefit and risk in the context of the number of patients one needs to treat to obtain benefit (NNT) compared with the number needed to treat for an adverse outcome (NNH). Efficacy and safety data are presented from IFN beta-1a (Rebif) clinical trials, including relevant NNT and NNH values, to allow assessment of the overall benefit-to-risk ratio compared with placebo. Additional comparisons are made with published data for other IFN products and GA. The indirect comparative information reviewed demonstrates that IFN appears to have a better benefit- to-risk ratio than GA. Indirect comparisons suggest better efficacy of thrice weekly (tiw) IFN beta-1a compared with alternate-day IFN beta-1b, but no direct comparative data are available. Direct comparative data show that IFN beta-1a at a dose of 44 mcg tiw has a favourable benefit-to-risk ratio compared with both 22 mcg tiw and 30 mcg once weekly, suggesting that 44 mcg tiw currently has the best benefit- to-risk ratio for the treatment of relapsing MS.