Among heavily pretreated patients with relapsed or refractory multiple myeloma, idecabtagene vicleucel (ide-cel) – a chimeric antigen receptor (CAR)-T cell therapy – may induce a response, although it carries a high rate of adverse events (AEs), according to research published in The New England Journal of Medicine.

Although many novel treatments have entered the multiple myeloma landscape in the past several decades, relapse is common, and the disease remains largely incurable. CAR-T cell therapy, which has been approved for use in B cell cancers, has shown promise in the myeloma setting, with ide-cel (also known as bb2121), which targets the B cell maturation antigen, showing good efficacy potential in a phase 1 study.

For the present phase 2 study, researchers evaluated the safety and efficacy of ide-cel in a group of patients with relapsed or refractory multiple myeloma who had received at least 3 lines of prior therapy. All patients were at least 18 years old and were enrolled between December 2017 and November 2018.

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Overall, 128 patients were enrolled and received 1 of 3 target CAR-positive T cell doses: 150 x 106 (4 patients), 300 x 106 (70 patients), and 450 x 106 (54 patients). In the total cohort, the median age was 61 years (range, 33-78), 76 (59%) patients were male sex, and 108 (84%) had at least triple-refractory disease.

The median follow-up period was 13.3 months. At this point, the overall response rate was 73%, with 33% of patients having a complete response or better. Out of the overall 128 patients treated, 33 patients (26%) were minimal residual disease (MRD)-negative . Additionally, 79% of the 42 patients with a complete response or better were MRD-negative. Patients in the 150 x 106 dose-group had a response rate of 50%, vs 69% in the 300 x 106 dose-group and 81% in the 450 x 106 dose-group.

The median progression-free survival period was 8.8 months; median overall survival was 19.4 months.

In the overall cohort, common AEs included neutropenia (91%), anemia (70%), thrombocytopenia (63%), and cytokine release syndrome (84%). Neurotoxic AEs were observed in 18% of patients, though none were higher than grade 3.

“Results of the KarMMa study support substantial antitumor activity for ide-cel across a target dose range of 150 × 106 to 450 × 106 CAR+ T cells,” the authors wrote. “The 450 × 106 dose appeared to be somewhat more effective than the other doses.”

Disclosures: Some authors have declared affiliations with or received funding from the pharmaceutical industry. Please refer to the original study for a full list of disclosures.


Munshi NC, Anderson LD Jr, Shah N, et al. Idecabtagene vicleucel in relapsed and refractory multiple myeloma. N Engl J Med. 2021;384(8):705-16. doi:10.1056/NEJMoa2024850