Merck's biopharmaceutical division Merck Serono has started an international Phase II trial designed to evaluate the efficacy and safety of MSB0010718C in patients with metastatic Merkel cell carcinoma (mMCC), a rare and aggressive type of skin tumour.
MSB0010718C is an investigational fully human IgG1 monoclonal antibody that binds to programmed death-ligand 1 (PD-L1).
The multicentre, single-arm, open-label Phase II trial is being carried out in patients with mMCC who have previously received one line of chemotherapy.
Around 84 patients across Asia Pacific, Australia, Europe and North America are expected to be enrolled in the trial. Its primary endpoint is overall response.
The PD-L1/PD-1 pathway is implicated as a major mechanism by which tumours evade elimination by the immune system. The PD-L1 molecule is expressed in many cancer types, including mMCC.
According to the company, MSB0010718C blocks the interaction of PD-L1 with PD-1 receptors and may have the potential to restore effective anti-tumour T-cell responses and thereby inhibit tumour growth.
Merck Serono Immuno-Oncology senior vice-president Helen Sabzevari said: "We believe that modulating the immune system by targeting PD-L1 represents a promising new approach in the treatment of this aggressive cancer, especially considering that many of the predisposing factors for mMCC seem to be related to functional disruptions of the immune system.
"Our anti-PD-L1 compound may present a potential new approach for the treatment of mMCC patients.
"The initiation of this Phase II study is an important milestone, as we endeavor to help those suffering from mMCC, a devastating disease with significant unmet need."
Apart from the new Phase II trial in mMCC, MSB0010718C is currently being assessed in a Phase I clinical trial for the treatment of solid tumours.
To date, the company has enrolled 422 patients with its aim to recruit 590 patients in the Phase I trial.
The trial is currently recruiting patients into expansion groups in seven cancer types, including castrate-resistant prostate cancer, colorectal cancer, gastric/gastroesophageal cancer, melanoma, metastatic breast cancer, non-small cell lung cancer and ovarian cancer.
Image: Micrograph of a Merkel cell carcinoma. Photo: courtesy of Nephron.