FDA approves Merck’s avelumab in MCC

The immune cancer therapy, which will be co-marketed by Pfizer for an annual cost of US$150,000 per patient, is the fourth immune checkpoint inhibitor triggering PD-1/PD-L1-directed T cell activation in solid tumours that has reached the US market. Merkel cell carcinoma is a rare but aggressive skin cancer affecting 2,500 patients in the US. However, market authorisation of the antibody in metastatic MCC comes just before the roll-out in eight broader solid cancer indications including NSCLC, RCC, bladder, gastric and ovarian cancer, in which Merck has pushed clinical testing of the compound to Phase III.

Merck and Pfizer are also evaluating avelumab in double and triple combination regimens with Pfizer’s T cell boosters, utomilumab, an 4-1BB agonist, and PF-04518600, an OX40 agonist. 

As avelumab’s accelerated FDA approval in metastatic MCC is based on the data of just 88 patients, analysts are yet waiting for long-term data to estimate what share of the projected US$30bn immuno-oncology market Merck KGaA could gain. In the trial, 28 patients, roughly a quarter, responded (8 complete responses) to the antibody, which previously received FDA breakthrough status, in a pivotal open-label Phase II trial. Merck’s checkpoint inhibitor is also under review for MCC in the European Union.

Despite having a late start in immuno-oncology, Merck has outperformed earlier adopters such as AstraZeneca. Currently BMS, Merck & Co. and Roche have PD1/PD-L1 modulators on the market. Astra Zeneca’ s PD-L1 blocker durvalumab is expected to reach the market this autumn in bladder cancer, an indication where Roche is marketing its PD-L1 blocker atezolizumab since last May.