B-cell-tailored dosing of ocrelizumab shows good results

In a randomised-controlled trial, B-cell-tailored dosing of ocrelizumab yielded encouraging results thus far. Results of an interim analysis of the BLOOMS trial showed very little radiological or clinical disease activity in either the personalised interval dosing (PID) or standard interval dosing (SID) group. Final results are expected in 2027.

Ocrelizumab and other anti-CD20 therapies are highly effective in relapsing-remitting MS, but there is a wide variety in B-cell reconstitution kinetics. Partial B-cell repopulation varies from 27 to 175 weeks after the last infusion. Cohort studies have already shown that with extended dosing intervals a low relapse rate is sustained [1,2].

To compare the efficacy of B-cell-tailored PID of ocrelizumab with SID in patients with relapsing-remitting MS, the ongoing investigator-initiated, non-inferiority BLOOMS trial (NCT05296161) was set up in the Netherlands [3]. The aim is to recruit 296 patients; the reported interim analysis included 163 participants currently enrolled. Participants are required to receive ocrelizumab treatment for a minimum of 48 weeks. They are randomised 1:1 to PID or SID of ocrelizumab. Infusions in the PID group will be extended as long as the CD19+ B-cell count remains below 0.01 10⁹/L (10 cells/μL). The co-primary outcome is the number of participants with relapses and/or new/enlarging T2-lesions.

Of 163 participants in the interim analysis, 87 were in the SID and 76 in the PID group. There was 1 relapse in both groups. The number of participants with new/enlarged T2-lesions was 2 in the SID group and 1 in the PID group. Any evidence of disease activity was seen in 3 and 2 participants in the SID and PID groups, respectively.

The number of participants thus far with an infusion interval was 63. The median interval was 8 months, the range was 6.0 to as long as 17.3 months. The drop-out percentage was 6.7 (n=11).

Final conclusions can only be drawn after the full cohort of patients completed the follow-up duration of 2 years.

1. Cucuzza CS, et al. Neurol Neuroimmunol Neuroinflamm. 2022 Nov 21;10(1):e200056.
2. van Lierop ZY, et al. Mult Scler. 2022;28(7):1121-25.
3. Hogenboom L, et al. B-cell tailored dosing versus standard interval dosing of ocrelizumab in relapsing-onset MS –Interim analysis of a randomized controlled trial (BLOOMS trial). Abstract O113, ECTRIMS 2024, 17–20 October 2024, Copenhagen, Denmark.

Medical writing support was provided by Michiel Tent

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Posted on 23 September 2024