Melflufen (PEPAXTO®) Receives FDA Approval for Relapsed/Refractory Multiple Myeloma

Today, a new treatment approach for multiple myeloma called melflufen (PEPAXTO^®)  was FDA approved for relapsed or refractory multiple myeloma patients who have received at least four prior lines of therapy and whose disease is refractory to at least one proteasome inhibitor, one immunomodulatory agent, and one CD38-directed monoclonal antibody. PEPAXTO is approved for use with the steroid dexamethasone. Oncopeptides, maker of PEPAXTO expects to have the intravenous drug to be available to physicians and patients within two weeks. 

Melflufen is the very first anti-cancer peptide-drug conjugate to be approved by the FDA, representing a new way to tackle multiple myeloma and cancer in general.

“Melphalan flufenamide is a novel and innovative therapeutic option which is active in patients with multiple myeloma who have a refractory disease, and the product has a manageable toxicity”, says Professor Ola Landgren, Chief of Myeloma Program and Leader of Experimental Therapeutics Program, Division of Hematology, Sylvester Comprehensive Cancer Center, University of Miami Health System in Miami, Florida. “Melphalan flufenamide will complement existing treatment regimens and contribute to address the growing unmet medical need among patients with relapsed or refractory multiple myeloma”.

The approval comes after review of the Phase II HORIZON study data which used melflufen (as an intraveneous administration) with the oral dexamethasone. The study included 157 patients and over half were triple-class refractory and had received at least four lines of treatment. The Overall Response Rate for the patients within this group of patients with refractory multiple myeloma was 23.7% and the Median Duration of Response was 4.2 months. Melflufen in combination with dexamethasone demonstrated activity in a subset of patients with Extra Medullary Disease (41%), an aggressive and resistant disease associated with a poor prognosis.

Additional data is expected from other studies in the coming months, such as the Phase III OCEAN study of 450 patients in over 100 centers, which is doing a head-to-head comparison between pomalidomide/dex vs. melflufen/dex. 

Melflufen does not work in the same way as melphalan, the drug commonly used for stem cell transplant. It's mechanism of action is completely different. At this point in time, melflufen will not replace melphalan as a transplant drug and will be used in the later treatment setting. 

We are excited that there is a new potential treatment for highly relapsed myeloma patients, especially those who have extra medullary myeloma, which is know to be higher risk myeloma. With additional myeloma treatment options like these, we can get closer to personalized care for all myeloma patients. 

To learn more about melflufen, click the links below: 

• Oncopeptides' Expanded Access Program for melflufen
• A Melflufen Update in Multiple Myeloma
• A New and Different Approach to Treat Triple Class Refractory Multiple Myeloma
• A Mid-Year Update with Paul Richardson, MD, Dana Farber Cancer Institute