STOCKHOLM—Oncopeptides AB has reported that the FDA has approved the company’s oncology drug Pepaxto (melphalan flufenamide, also known as melflufen), in combination with dexamethasone, for the treatment of adult patients with relapsed or refractory multiple myeloma 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 the first anticancer peptide-drug conjugate that has been approved for multiple myeloma.
This indication has been granted under accelerated approval, based upon the HORIZON trial. The HORIZON study evaluated intravenous Pepaxto in combination with dexamethasone, and included heavily pretreated patients with a poor prognosis. This multi-center single arm study evaluated 157 patients with relapsed or refractory multiple myeloma, of whom 97 were triple-class refractory and had received at least four prior lines of treatment. The overall response rate for the patients within this group of patients with refractory multiple myeloma was 23.7 percent, and the median duration of response was 4.2 months.
“While the treatment landscape for multiple myeloma has dramatically improved in recent years, once patients become resistant to existing classes of therapy they can face a very guarded prognosis,” said Dr. Paul G. Richardson, clinical program leader and director of Clinical Research at the Jerome Lipper Multiple Myeloma Center of the Dana-Farber Cancer Institute.
“Research has shown melphalan flufenamide to be a novel and innovative therapeutic option, which is active in refractory disease and has manageable toxicity, with the convenience of being administered by infusion once a month,” added Richardson. “Based on our findings, melphalan flufenamide is an important addition to the treatment armamentarium, with the potential to meaningfully improve outcomes in an area of important unmet medical need.”
Pepaxto is administered as a once monthly thirty-minute infusion. Oncopeptides plans to begin promoting Pepaxto to healthcare professionals across the US immediately, and expects a labeled product in distribution centers and specialty pharmacies within a few weeks.
“We are proud to bring forward the first anticancer peptide-drug conjugate approved by the FDA for multiple myeloma. Pepaxto uses innovative technology that links a peptide carrier to a cytotoxic agent. The conjugated agent is a highly lipophilic compound, which allows it to be rapidly distributed into cells,” explained Jakob Lindberg, chief scientific officer at Oncopeptides. The compound then leverages amino peptidases that are overexpressed in multiple myeloma cells, causing the release of the cytotoxic payload.”
“When we listed Oncopeptides on Nasdaq Stockholm, we promised to establish melflufen as an attractive treatment option for patients with multi-resistant disease. With the approval of Pepaxto, that has finally become reality,” Lindberg continued. “I am immensely proud of the relentless dedication of our organization and development partners around the world who have made this journey possible.”
“Moving ahead, our focus is to further advance Pepaxto. We look forward to receiving top line data from the Phase 3 OCEAN study in the second quarter,” noted Marty Duvall, CEO of Oncopeptides. “This comparative study with pomalidomide is designed to support a future supplementary New Drug Application to expand the label.”
Oncopeptides also reported back in December that the first patient had been dosed in the Phase 3 LIGHTHOUSE study, evaluating the efficacy and safety of a triple combination therapy with Pepaxto plus dexamethasone and subcutaneous daratumumab, compared to daratumumab alone.
“Following the encouraging results of our ANCHOR study, this is an important study to further evaluate the potential role of melflufen in triplet regimens,” Dr. Klaas Bakker, chief medical officer of Oncopeptides, pointed out in a press release. “There is an imminent need for additional therapeutic options as myeloma patients become multi-resistant earlier in their treatment journey. A positive outcome may potentially support the use of melflufen as combination therapy with daratumumab in earlier stages of multiple myeloma.”
Oncopeptides had reported updated efficacy and safety data from its ongoing Phase 2 ANCHOR combination study earlier in December, as well. The data showed that a triplet regimen with Pepaxto plus dexamethasone, in combination with daratumumab or bortezomib, in heavily pretreated patients with relapsed refractory multiple myeloma demonstrated encouraging activity.
The therapy was well tolerated in the ANCHOR trial, and had a similar safety profile as when used as a doublet regimen in the HORIZON trial. The reported severe treatment-related adverse events were primarily hematologic, and were clinically manageable with dose reduction.
“The ANCHOR data are very promising: both combinations are well tolerated and demonstrated encouraging activity. The data support further development of melflufen in triplet regimens. We are preparing study start in close dialogue with relevant authorities and expect to enroll the first patient during the first quarter of 2021,” Bakker stated.