Dr Spencer on Early Efficacy Data for In Vivo CAR T-Cell Therapy in R/R Myeloma

What is important here, even though it wasn't the primary end point of the study, is that [at] the 1-month time point, all [evaluable] patients who had results available [were] MRD negative at 10^-5 [sensitivity].

Andrew Spencer, MBBS, FRACP, FRCPA, DM, a professor of hematology at Monash University and head of the Malignant Hematology, Transplantation, and Cellular Therapy Service and the Myeloma Research Group at The Alfred Hospital, discussed key findings from the phase 1 inMMyCAR trial (NCT07075185) evaluating the in vivo CAR T-cell therapy KLN-1010 in patients with relapsed or refractory multiple myeloma.

Data presented by Spencer at the 2026 EHA Congress showed that among efficacy-evaluable patients (n = 18), KLN-1010 generated an overall response rate (ORR) of 100%, comprising a stringent complete response (sCR) rate of 22%, a CR rate of 6%, a very good partial response (VGPR) rate of 22%, and a PR rate of 50%. In 6 patients with at least 4 months of follow-up, 67% achieved a sCR, and 33% had a VGPR. In 14 patients evaluable for minimal residual disease (MRD), all were MRD negative at a 10^-5 sensitivity.

Although the current dataset is too small to determine whether particular patient populations derive greater benefit than others, Spencer noted that ongoing analyses will evaluate these questions as enrollment and follow-up continue. He stressed that one of the most notable findings to date was the achievement of MRD negativity at the 1-month assessment. Although MRD negativity was not the primary end point of the study, Spencer described the uniformity and rapidity of these responses as an unexpectedly strong efficacy signal.

As of data cutoff, Spencer reported that only 1 patient had experienced disease progression, and 1 additional patient lost MRD negativity. He cautioned that no therapy is expected to achieve universally durable responses, but also emphasized that these early outcomes compare favorably with expectations for heavily pretreated patients with relapsed or refractory multiple myeloma.

The combination of universal early MRD negativity, limited disease progression to date, and encouraging pharmacodynamic findings supports continued clinical development of in vivo CAR T-cell therapy, Spencer concluded.