At ASH 2025 we presented the data from our pivotal phase II iMMagine-1 study of anitocabtagene autoleucel, antio-cel, in patients with relapsed/refractory multiple myeloma. In this study our data cut-off date for this data was October 7th 2025. So far we had 117 patients with a median follow-up of 15.9 months and all patients received a single infusion of anito-cel. The target dose of cells was 115x106 CAR-positive viable T-cells.
What was interesting about this CAR T-cell, different from other BCMA CARs, is the way that the CAR actually attaches to myeloma. Instead of a traditional scFv for BCMA it actually has something called a D-domain which is a smaller protein which improves induction or transduction of the CARs onto the cells and, again, why maybe our target dose of CAR T-cells is a bit lower in this study compared to other CAR Ts. The other piece is that maybe because the CAR T is able to come off the target faster that maybe it causes less inflammation and potentially causes less toxicity.
The updated data we presented was the overall response rate which has been deepening. It was 96% and the complete response, stringent CR rate, was actually 74%. The vgPR rate was 88% and this was all based on an independent review committee assessment.
The other big data we presented was our MRD testing data and at the time of the data cut-off 95% of patients achieved overall MRD undetectability at 10-5 and for patients that had a sufficient follow-up at six months or greater 83% actually had sustained MRD undetectability at 10-5.
In terms of PFS we were able to show that the 18-month PFS rate was 67.4%, at 24 months it’s now 61.7%. So we have not reached median PFS as of yet. Overall survival median has not been reached either and at 24 months is 83%.
The other important safety data was that there are no delayed or non-ICANS neurotoxicities, including Parkinsons, Parkinsonism, cranial nerve palsies or Guillain-Barré syndrome. We have not seen any immune effector cell associated entercolitis as of yet either. The last patient dose was more than 12 months ago.
So the preliminary results from the phase II iMMagine-1 study continue to demonstrate that deep and durable response and the safety profile is very predictable and manageable. This was in patients in a fourth line plus relapsed/refractory population and patients who are triple- and penta-refractory disease.
What is the clinical significance of these results and what is next for this study?
Again, with the great response rates and PFS which has not reached median yet but looks really good, even at the 24-month mark, we always want therapies that are going to improve survival for our patients but safety is just as important and quality of life is really important. So CAR T is the one thing that offers a ‘one and done’ for our myeloma patients who, for the most part, have been dealing with therapy continuously their entire lives since their diagnosis. So I do think that ‘one and done’ aspect is really unique for CAR Ts in general but the fact that, again, we don’t see some of the toxicities that we’ve seen with our other CAR Ts but with this great response, hopefully it will improve access to CAR T for our patients. So, again, if we can do this outpatient, for instance, which 8% of our patients were outpatient, but we can learn how to do this in maybe not just big hospitals like mine, more of our patients who have myeloma can actually get CAR T therapy. I think that’s always really exciting, that more access is really, really important for our patients.
