Roche's Ocrevus Phase 4 Trial Discontinuation Study Tracks Early Relapsing Multiple Sclerosis
Clinical Design and Progress
AMS05, led by NIAID in collaboration with Genentech and the Autoimmunity Centers of Excellence, is a U.S. Phase 4 trial evaluating the possibility of discontinuing Ocrevus (ocrelizumab) in patients with relapsing multiple sclerosis (RMS). Ocrelizumab is a humanized monoclonal antibody targeting CD20 on B lymphocytes and is currently marketed for RMS. The study, which began in January 2023, aims to enroll 123 patients aged 18 to 55, with a primary completion date set for May 2030.
Structure to Validate Discontinuation
All participants receive 300mg on Day 1 and Day 14, followed by 600mg every 6 months for 24 months. At 24 months, participants are randomized 2:1, with the discontinuation group receiving placebo and the continuation group receiving ocrelizumab every 6 months until 48 months in a double-blind design. The primary endpoint is the proportion of participants without clinical relapse between 24 and 48 months, with frequent 3-tesla MRI scans monitoring new inflammatory lesions. This design directly evaluates how long disease suppression persists after B-cell depletion, rather than simply extending dosing intervals.
Regulatory Status and Competitive Landscape
The U.S. FDA approved Ocrevus for the treatment of relapsing and primary progressive multiple sclerosis on March 28, 2017, and the European Union authorized its sale on January 8, 2018. Other CD20-targeting competitors include Novartis's Kesimpta (ofatumumab) and TG Therapeutics's Briumvi (ublituximab-xiiy), with FDA approvals on 2020 and December 28, 2022, respectively. Standard treatments also include Tysabri (natalizumab), Tecfidera (dimethyl fumarate), and Aubagio (teriflunomide), offering a broad range of options. The key distinction of this study is not to demonstrate superiority over other drugs, but to answer whether high-efficacy treatment must be continued for life.
Implications for Patients, Market, and Revenue
According to GlobalData, the global multiple sclerosis treatment market was USD 32.8 billion in 2024 and is projected to reach USD 41.2 billion by 2034. Ocrevus generated CHF 7.01 billion in revenue in 2025, a 9% increase from the previous year, maintaining its position as a core growth product for Roche. If the discontinuation group shows sustained relapse suppression, it could provide evidence to reduce cumulative dosing frequency and injection-related burdens, though shorter treatment duration may lower per-patient revenue in the long term. Conversely, if the continuation group demonstrates superiority, it could reinforce the clinical rationale for maintaining the 6-month dosing interval and revenue sustainability.
From an investor perspective, the ongoing Phase 4 trial with 123 participants is a study to validate the long-term treatment duration and patient lifetime value of Ocrevus, which generated CHF 7.01 billion in revenue in 2025. For researchers, it provides a prospective, randomized, double-blind measurement of whether clinical relapse and MRI inflammation suppression can be maintained for more than 24 months after CD20-positive B-cell depletion. For the industry, it could provide evidence to influence discontinuation and re-treatment strategies for similar CD20-targeting products in the USD 32.8 billion global multiple sclerosis market in 2024. While direct revenue changes are limited until the primary completion in May 2030, success could reinforce reduced treatment burden and shorter dosing duration, while failure could strengthen the clinical justification for continued maintenance therapy.
Source: ClinicalTrials.gov (api_ct)