The U.S. FDA approved a new formulation of melphalan injection for use as a high-dose conditioning treatment prior to hematopoietic cell transplantation in multiple myeloma (MM) patients and for the palliative treatment of MM patients for whom oral therapy is not appropriate. This is the first product to be approved for the high-dose conditioning indication in MM. The new formulation of melphalan does not contain propylene glycol and can be stabilized at room temperature for four hours in addition to the one hour following reconstitution.
Approval was granted based on results from a multi-center, open-label, phase IIb trial in which 61 patients received 200 mg/m2 of this melphalan formulation followed by transplant. The overall response rate was 95 percent, and the complete response rate was 31 percent. All patients had successful myeloablation and subsequent neutrophil and platelet engraftment with no mortality reported at day 100.
The drug has a Boxed Warning for severe bone marrow suppression, hypersensitivity, and leukemogenicity. The most common adverse events (observed in ≥50% of patients) were neutropenia, leukopenia, lymphopenia, and thrombocytopenia. Diarrhea, nausea, fatigue, hypokalemia, anemia, and vomiting were the most common non-hematologic adverse events.
Source: Spectrum Pharmaceuticals press release, March 15, 2016.