Amgen announced top-line results from the primary overall survival (OS) analysis of a phase 3 trial in melanoma, which evaluated the efficacy and safety of talimogene laherparepvec for the treatment of unresected stage IIIB, IIIC or IV melanoma compared to treatment with subcutaneous granulocyte-macrophage colony-stimulating factor (GM-CSF).

Results showed that, while the primary end point of durable response rate was met (as previously reported), the secondary endpoint of OS was not met, although there was a strong trend in favour of talimogene laherparepvec (p=0.051). The estimated OS hazard ratio and improvement in median OS were similar to what was previously reported at the interim OS analysis.

Talimogene laherparepvec is an investigational oncolytic immunotherapy designed to selectively replicate in tumours and to initiate an immune response to target cancer that has metastasized, or spread to other areas of the body.

"We remain encouraged that the study met its primary endpoint of achieving durable responses in patients with metastatic melanoma," said Sean E. Harper, managing director, executive vice president of research and development at Amgen. "We missed statistical significance on the secondary endpoint of overall survival but the strong trend in survival benefit supports further research of talimogene laherparepvec to better understand its role in melanoma, both as a single-agent and in combination with other therapies."

The global, randomised, open-label Phase 3 trial enrolled patients with unresected stage IIIB, IIIC or IV melanoma. Patients were randomized 2:1 to receive either talimogene laherparepvec every two weeks through direct tumour injection or GM-CSF subcutaneously for the first 14 days of each 28-day cycle, for up to 18 months.

The most frequent adverse events observed in this trial were fatigue, chills and pyrexia. The most common serious adverse events include disease progression, cellulitis and pyrexia.

Talimogene laherparepvec is an investigational oncolytic immunotherapy designed to selectively replicate in tumours (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 tumours where it replicates inside the tumour's cells causing the cell to rupture and die in a process called lysis. The rupture of the cancer cells can release tumour-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.

Melanoma is a type of skin cancer that is characterized by the uncontrolled growth of melanocytes, which are the cells responsible for providing the pigment to skin.1 Melanoma is the most aggressive and serious form of skin cancer. Currently, 132,000 melanoma cases occur globally each year.2 In the US., while melanoma accounts for less than five percent of skin cancer cases, it causes the most skin cancer deaths.2 The number of new cases of melanoma in the US. has been increasing for the last 30 years.

Melanoma is considered to be advanced when it has spread, or metastasized, from the origin site to deeper parts of the skin or other organs such as the lymph nodes, lungs or other parts of the body distant from the primary tumour site.3