Distinguishing Strategic Roles of CELMoDs in Multiple Myeloma

Paul G. Richardson, MD, director of Clinical Research and Clinical Program Leader at the Jerome Lipper Multiple Myeloma Center, the Dana-Farber Cancer Institute and RJ Corman Professor of Medicine, Harvard Medical School, detailed the significant clinical potential of the cereblon E3 ligase modulators (CELMoDs), iberdomide and mezigdomide, that he discussed in a presentation hosted by the Miami Cancer Institute.

He highlighted the 2 CELMoDs and their distinct roles in the evolving myeloma treatment landscape. Mezigdomide has demonstrated particularly striking efficacy in highly refractory patient populations. When utilized as a doublet therapy with dexamethasone, it achieved a response rate of approximately 40% to 50%. Notably, the molecule was specifically designed for superior tissue penetration, allowing it to overcome the challenges of extramedullary disease, where it has produced remarkable clinical responses.

The synergy of mezigdomide becomes even more apparent when integrated into combination regimens. Richardson noted that combining mezigdomide with the proteasome inhibitor bortezomib (Velcade) increases response rates to 90%. Furthermore, combinations with carfilzomib (Kyprolis) have yielded response rates in the region of 80%. Critically, these high levels of activity are observed even in patients who were previously exposed to these specific proteasome inhibitors, marking a significant observation for the treatment of resistant disease.

In comparison, iberdomide also exhibits strong synergy but at a slightly lower level of potency. As a doublet with dexamethasone, iberdomide results in response rates of roughly 25% to 30%. Although its activity increases significantly when paired with agents like daratumumab (Darzalex) or bortezomib, the results generally do not reach the same peaks seen with mezigdomide combinations.

These varying levels of potency and tolerability allow for a strategic positioning of both agents. Richardson envisions iberdomide being utilized in early relapse settings or even as a frontline maintenance therapy due to its benign safety profile. Mezigdomide, conversely, is being developed as the agent of choice for the relapsed/refractory setting, serving a role similar to but more powerful than, pomalidomide. This dual-track development strategy ensures that oral CELMoDs can serve as versatile backbone therapies across the entire spectrum of the disease.