Results from a phase II study in patients with newly diagnosed multiple myeloma (MM) indicate that, at 12 months, iberdomide is an effective post-autologous hematopoietic cell transplant (AHCT) maintenance strategy, with a favorable safety profile and superior response improvement when compared with lenalidomide maintenance. Niels W.C.J. van de Donk, MD, a hematologist at University Medical Center in Amsterdam, Netherlands, led the study and presented the efficacy and safety results at the 65th ASH Annual Meeting and Exposition.
“The big advantage of iberdomide is that it is an orally available drug,” Dr. van de Donk said.
Dr. van de Donk began his presentation by explaining that, while maintenance with lenalidomide is the standard of care after high-dose chemotherapy and AHCT, patients not only relapse, but they also discontinue treatment because of adverse events (AE). Thus, the community needs a drug with a more acceptable tolerability profile, he explained.
Iberdomide is a new, potent oral cereblon E3 ligase modulator with greater tumoricidal and immune-modulatory effects than lenalidomide. The new immunostimulatory drug has been shown in a phase I/II clinical trial to not only have a good safety profile but to also be effective in the treatment of patients with triple-class refractory MM. Dr. van de Donk and colleagues thus designed the EMN26 study to evaluate whether iberdomide could be a better option than lenalidomide for maintenance therapy of patients with MM.
EMN26, an ongoing phase II European multicohort study conducted in four countries, enrolled patients with MM who have achieved at least a partial response after induction therapy containing a proteosome inhibitor plus lenalidomide and pomalidomide followed by single or double AHCT +/- consolidation. Approximately 20% of patients had MM with high-risk cytogenetics. The study began with two doses of iberdomide (1.0 and 1.3 mg), and then a third dose of 0.75 mg was added to the protocol.
“These days, in multiple studies, we are treating a larger number of patients with multiple doses to come up with a good proposal for a maintenance dose,” Dr. van de Donk said in an interview. The median follow-up was 14.6 months for the 1.3 mg cohort, 17 months for the 1.0 mg cohort, and 4.7 months for the 0.75 mg cohort. Because of the short follow-up of the 0.75 mg cohort. Dr. van de Donk focused his presentation on the higher-dosed cohorts.
At six months, 42% of patients in the 1.3 mg cohort had an improvement in response, and 45% of those in the 1.0 mg cohort had an improvement in response. The response rate improved over time such that at 12 months 50% of the 1.3 mg cohort had an improvement in response and 54% of the 1.0 mg cohort had an improvement in response. Neutropenia was the main hematologic side effect. Most non-hematologic adverse events (AE) were low grade, and there were no second primary malignancies reported.
Dr. van de Donk concluded his presentation by describing the phase III EXCALIBER study, which is now enrolling. The head-to-head randomized study will continue to define the recommended maintenance dose and will directly compare iberdomide to lenalidomide.
Any conflicts of interest declared by the authors can be found in the original abstract.
Reference
van de Donk NWCJ, Touzeau C, Terpos E, et al. Iberdomide maintenance after autologous stem-cell transplantation in newly diagnosed MM: First results of the phase 2 EMN26 study. Abstract 208. Presented at the 65th American Society of Hematology Annual Meeting and Exposition; December 9, 2023; San Diego, California.