While CELMoDs frequently cause neutropenia, this effect is most pronounced in early cycles and manageable with growth factors. This contrasts sharply with the persistent, quality-of-life-impairing non-hematologic side effects of lenalidomide, such as rash and severe fatigue. This trade-off results in a significantly better long-term tolerability profile for patients.
An expert who initially viewed CELMoDs as incremental improvements now considers them fundamentally different. The new litmus test for future myeloma trials will be tracking prior patient exposure to CELMoDs like iberdomide, just as they track prior IMiD exposure today, cementing their status as a distinct therapeutic category.
Unlike older IMiDs where T-cell effects are secondary, CELMoDs have a powerful, independent pro-T-cell mechanism. This dual action is so significant that in the future, CELMoDs will be prescribed not just for their direct anti-myeloma effects, but specifically to enhance the efficacy of T-cell therapies like CAR-T and bispecific antibodies.
In newly diagnosed, transplant-ineligible myeloma, an iberdomide-based triplet (Iber-Dara-Dex) achieved 64% MRD negativity. This result is described as "astounding" because achieving MRD negativity is not even a realistic goal for comparable IMiD-based triplets like Dara-Len-Dex (the MAYA regimen). This sets a dramatically higher efficacy bar for frontline treatments.