Mrinal S. Patnaik, MBBS

Mrinal S. Patnaik, MBBS, Associate Professor of Internal Medicine and Oncology and a consultant in hematology at the Mayo Clinic, Rochester, commented on the MEDALIST trial for The ASCO Post. “Given its unique mode of action, relative ease of administration, and excellent tolerability, luspatercept is an exciting modality to treat anemia in patients with myelodysplastic syndromes (MDS).”

Dr. Patnaik noted the significant morbidity and mortality among patients with lower-risk MDS and transfusion-dependent anemia. Erythropoietin-stimulating agents are a key treatment modality in these patients, but they are effective in a select group, he noted.

Published studies have shown that low transfusion dependence, a morphologic diagnosis of refractory anemia or refractory anemia with ring sideroblasts, the use of a fixed-dose vs weight-based erythropoietin regimen, a shorter time from diagnosis to starting treatment, and a lower serum erythropoietin level are predictive of response to erythropoietin-stimulating agents. In these patients, the response rate is approximately 50%, and the median duration of response is about 12 to 18 months. Recurrent anemia after failure of an erythropoietin-stimulating agent or patients who are nonresponsive to or ineligible for these agents are often difficult to treat, with limited options being androgens, lenalidomide, or hypomethylating agents—drugs associated with side effects, he pointed out.

‘Revolutionizing’ Management of Anemia

“The advent of agents such as luspatercept and sotatercept, which bind to select transforming growth factor-ß superfamily ligands such as GDF11 to reduce aberrant Smad2/3 signaling—thus enhancing the late stages of erythropoiesis—has revolutionized the management of anemia in MDS,” Dr. Patnaik said. “In the MEDALIST trial, 37.9% of patients on the luspatercept arm achieved the primary endpoint of red cell transfusion independence for 8 weeks, vs 13.2% in the placebo arm (P < .0001), and 28% achieved red cell transfusion independence for 12 weeks. These numbers are very hard to achieve with alternative strategies.… Future evaluations in additional MDS subtypes and other myeloid neoplasms, such as MDS/myeloproliferative neoplasm overlap syndromes, will be needed for broader applicability,” he added.

David P. Steensma, MD

Press briefing moderator David P. Steensma, MD, Associate Professor of Medicine at Harvard Medical School and Institute Physician at Dana-Farber Cancer Institute in Boston, noted that the responses seen in the placebo arm in the MEDALIST study “highlight a challenge in formally measuring clinical responses in MDS, given that the disease course and transfusion needs fluctuate. A proposed revision to the International Working Group response criteria should help clarify this,” he told journalists.

At Last: Potentially Useful Agent in MDS

However, Dr. Steensma agreed that luspatercept has the potential to become a useful agent in MDS. “Luspatercept is clearly an active drug, and its safety profile seems quite benign. This will be useful for some patients with ring sideroblasts, who constitute about 20% of patients overall but who are overrepresented among the clinic population receiving transfusions, since they tend to have more severe anemia and survive longer than those with some other MDS subtypes,” he said. “A key question is whether luspatercept will be useful in the larger group of anemic patients with MDS without ring sideroblasts, and that is now being studied in the COMMANDS trial. We’ll have to watch for cost-effectiveness once the drug’s price is announced. The duration of response in MEDALIST was not as long as I’d hoped, and only a minority of patients responded. But still, it will help to have this as an option for MDS treatment.”

He added that luspatercept could become the first drug to be approved in MDS in 12 years, whereas 8 agents were approved these past 2 years for acute myeloid leukemia. “We’re overdue for a new treatment for MDS,” Dr. Steensma commented. ■

DISCLOSURE: Dr. Patnaik’s institution has received funding from Stem Line Therapeutics. Dr. Steensma’s institution has received research funding from Celgene, Aprea, and H3 Biomedicine; and he has received funds for data safety monitoring committee service from Onconova and Janssen.