Amgen announced in May the publication of primary results from the Phase 3 OPTiM study in the Journal of Clinical Oncology (JCO). The data published in JCO, which were previously presented at the Annual Meetings of the American Society of Clinical Oncology (ASCO) in 2013 and 2014, demonstrated a significantly higher durable response rate (DRR) in patients with unresected stage IIIB, IIIC or IV metastatic melanoma receiving the investigational oncolytic immunotherapy talimogene laherparepvec compared to those who received granulocyte-macrophage colony-stimulating factor (GM-CSF). Results showed that the primary endpoint of DRR was met, however the secondary endpoint of overall survival (OS) was not met, although there was a strong trend in favor of talimogene laherparepvec.
A DRR measures the number of patients who had a complete response or partial response within the first 12 months of treatment and maintained the response continuously for at least 6 months. The most frequent adverse events (AEs) observed in this study were chills, pyrexia, injection-site pain, nausea, flu-like symptoms and fatigue. The most common serious AEs included disease progression, cellulitis and pyrexia. No treatment-related deaths were observed. The OPTiM data serve as the basis of a Biologics License Application which has been accepted for review by the U.S. Food and Drug Administration (FDA), and a Marketing Authorization Application in the European Union for talimogene laherparepvec for the treatment of adults with regionally or distantly metastatic melanoma.
The FDA has set a review goal date under the Prescription Drug User Fee Act of Oct. 27, 2015. The OPTiM study was a global, randomized, open-label, Phase 3 trial designed to evaluate the safety and efficacy of talimogene laherparepvec compared to a control therapy with GM-CSF in over 400 patients with unresected stage IIIB, IIIC or IV melanoma. Patients were randomized 2:1 to receive either talimogene laherparepvec intralesionally every two weeks or GM-CSF subcutaneously for the first 14 days of each 28 day cycle. Treatment could last for up to 18 months. Where appropriate, stable or responding patients could receive additional treatment on an extension protocol. Talimogene laherparepvec is an investigational oncolytic immunotherapy designed to selectively replicate in tumors (but not normal tissue) and to initiate an immune response to target cancer cells that have metastasized.
Talimogene laherparepvec was designed to work in two important and complementary ways. First, it is injected directly into tumors where it replicates inside the tumor’s cells causing the cell to rupture and die in a process called lysis. Then, the rupture of the cancer cells can release tumor-derived antigens, along with GM-CSF, that can stimulate a system-wide immune response where white blood cells are able to seek out and target cancer that has spread throughout the body.