Melflufen Combo Earns FDA Priority Review for Triple-refractory Myeloma

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by Patricia Inacio PhD |

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The U.S. Food and Drug Administration (FDA) has granted priority review to Oncopeptide’s application seeking accelerated approval of melflufen (melphalan flufenamide) plus dexamethasone for people with relapsed or refractory multiple myeloma (RRMM).

The new drug application was submitted in July and based on promising data from the HORIZON Phase 2 trial (NCT02963493). It is specific for people with triple-refractory disease — those who failed to respond to at least one immunomodulatory agent (IMiD), one proteasome inhibitor, and one anti-CD38 monoclonal antibody. A decision is expected in February.

Meanwhile, Oncopeptides has launched an early access program — called sEAPort (NCT04534322) and active since Sept. 1 — that makes melflufen available in the U.S. before its approval. Myeloma patients with triple-refractory disease are eligible for the program; more information can be found here.

“This is very exciting news. It is an important milestone for Oncopeptides, and a major step in making melflufen available for patients with multiple myeloma, who desperately need new treatment options,” Marty J Duvall, CEO of Oncopeptides, said in a press release.

“I am looking forward to a continuing dialogue with the FDA while we make the product available to RRMM patients in the US through an expanded access program, in an FDA approved trial called sEAPort,” Duvall said.

Melflufen is an investigational peptide-drug conjugate that delivers a cancer-killing agent specifically to cancer cells. The agent is fully active only in the presence of aminopeptidases, a special class of enzymes that exist at high levels in cancer cells.

The HORIZON trial included 157 patients who had received at least two prior therapies, including one IMiD and one proteasome inhibitor, and failed to respond to treatment with Darzalex (daratumumab) and/or Pomalyst (pomalidomide).

All received the combination of melflufen plus dexamethasone for up to two years.

Among patients with triple-refractory disease, 26% responded to treatment and these responses lasted a median of 4.4 months. Patients lived without disease progression for a median of 3.9 months, which increased to 8.5 months among those who responded to treatment. Overall survival was 11.2 months.

Regarding safety, most patients (94%) reported severe or life-threatening side effects, and these were mostly low levels of some immune cell type. Also, 10 patients died in the trial due to adverse events, but none was linked to treatment.

The designation of priority review is given by the FDA to medicines that treat a serious medical condition and provide significant advantages to currently available treatments. It shortens the revision time from the standard 10 months to six months.

The FDA has signed a Prescription Drug User Fee Act (PDUFA), which allows the federal agency to collect fees from manufacturers to expedite the approval process, with a target date of Feb. 28, 2021. By then, the FDA must come to a decision on whether melflufen plus dexamethasone should be approved for this indication.