IMS 2026 | Real-world outcomes with BCMA bispecifics after belantamab mafodotin in multiple myeloma

So, we performed at the Royal Marsden Hospital an evaluation of our patients that started T-cell-engaging bispecific antibody therapy against BCMA. We focused particularly on a group of patients that started the treatment relatively early on, so we have actually long follow-up. We limited our analysis to patients that had at least one year of follow-up, which is longer than many of the real-world analyses. And our knowledge of our population was, of course, that some of them have had prior BCMA-targeting ADC treatments with Belantamab. And one of the big questions with these drugs that target BCMA is at the moment, can we give them one after the other? And does it potentially have a negative impact on the effect of targeting the same target twice? So first with the ADC and then the bispecific. So we considered all of our patients that received bispecific antibody with either the standard of care treatment Teclistamab or elranatamab that is reimbursed in the UK and then looked into whether they have had prior ADC therapy with Belantamab or not. So we had a subgroup of patients that was a well-balanced analysis actually. It was roughly 50-50 patients that did or did not have the prior ADC treatment. And we were ourselves actually very positively surprised that these patients had very similar response rates, but particularly the long-term progression-free survival was identical practically for these two populations. So we really see these patients. I have these patients in my daily practice as well that are now staying on over a year of remission time with a BCMA bispecific antibody with having had the ADC treatment just before. And I think a special characteristic of our analysis is that most patients had the ADC immediately before starting the treatment with the bispecific and were truly refractory to the ADC. So there seem to be non-overlapping resistance mechanisms that makes it possible, at least for quite a significant proportion of patients, to still benefit a lot from T-cell engagement therapy even if they had BCMA ADC before when it targets the same class of actions. We did some internal analysis in the data set to make sure that the data set is not just unusual. So we looked at for example whether cytogenetics are associated with outcome in the T-cell engager group or extramedullary disease. And both of them had an effect that was consistent with what has been demonstrated before. So for example, extramedullary disease was associated with an inferior outcome with the T-cell engager treatment. High-risk cytogenetics was also associated with an inferior outcome. Interestingly, we did see in the group of no high-risk cytogenetic abnormalities a really striking progression-free survival of long-term follow-up over a year that was well above 50%. So we are really thinking that it is useful to test genetics also in that relapsed refractory group. As we perform this analysis and have seen a reassuring result of patients still responding to BCMA T-cell engager after BCMA ADC therapy, we think this can be quite reassuring for countries where, for example, second-line treatment is limited to ADCs. This is the case at the moment in the UK. Second-line center of care treatment is Belantamab Velcade or Belantamab Pomalidomide Dexamethasone. And of course, every physician starting such a treatment is wondering at the moment, might this have a negative impact on subsequent bispecific antibody therapy? We have not seen such an effect in our analysis that is positive, that is good for the patients. It actually is in keeping with some translational results that have been generated as part of the belantamab development program as well, where patients still express BCMA by soluble BCMA when they relapse from Belantamab. It might be an indicator that Belantamab is actually a targeted chemotherapy rather than an immune-targeting agent like the T-cell engagers. And overall, I think it gives us all hopefully hope, although more data is needed, that we can actually really use these drugs sequentially, which is great because it offers an extra line of treatment for patients.

This transcript is AI-generated. While we strive for accuracy, please verify this copy with the video.