Pepaxto withdraws from the US market: Phase 3 clinical failure in the treatment of multiple myeloma

Pepaxto is the first anti-cancer peptide-drug conjugate (PDC), which can efficiently introduce the alkylating agent melphalan into myeloma cells

On October 22, 2021, Oncopeptipes AB announced that it has decided to withdraw the targeted anticancer drug Pepaxto (melphalan flufenamide, also known as melflufen) from the US market

Pepaxto was approved by the US FDA on February 26, 2021, in combination with dexamethasone, for the treatment of adult patients with relapsed or refractory multiple myeloma (MM)

Oncopeptides said that in the dialogue with the FDA, the agency apparently did not believe that the Phase 3 OCEAN study met the criteria for confirmatory research

In September of this year, Oncopeptides announced the data from the Phase 3 OCEAN study at the 18th International Myeloma Symposium (IMW) held in Vienna

The results announced at the IMW meeting showed that according to the independent review committee (IRC) assessment, the study reached the primary endpoint of progression-free survival (PFS): the median PFS in the Pepaxto group was 6.

Extensive analysis of pre-specified subgroups of data indicated that Pepaxto’s PFS benefit was primarily driven by patients who had not previously received autologous stem cell transplantation (ASCT).

In this study, compared with pomalidomide + dexamethasone, Pepaxto + dexamethasone treatment resulted in a significant increase in grade 3/4 hematological adverse events

Pepaxto (melflufen) is a lead drug from Oncopeptides' proprietary peptide-drug conjugate (PDC) platform.

Melflufen is activated by aminopeptidase, which is present in all human cells but is overexpressed in many cancers, including myeloma

Pepaxto Key Phase 2 HORIZON Clinical Study Data

Previously, the FDA accelerated the approval of Pepaxto, based on the results of the pivotal Phase II HORIZON study

The results showed that among the 97 patients, the overall response rate (ORR) was 23.

Conclusion: The combination of melflufen and dexamethasone will provide an important treatment option for adult patients with relapsed or refractory MM who are difficult to treat and have a poor prognosis, including three-drug refractory myeloma patients and extramedullary diseases (EMD).

Reference article: Oncopeptides withdraws Pepaxto® in US, scale down organization and focus on R&D