Merck KGaA, Pfizer’s PD-L1 hope shows potential in rare skin cancer

Merck kgaa HQ

German Merck and research partner Pfizer ($PFE) have posted positive data for their checkpoint inhibitor avelumab in a rare, aggressive and deadly form of skin cancer.

The two companies’ avelumab--which inhibits PD-L1 interactions--showed in a midstage trial of 61 patients that about 30% of those with Merkel skin cell carcinoma who had failed on a previous treatment saw their tumors shrink or disappear when treated with the experimental cancer immunotherapy.

Merkel skin cell carcinoma develops in the top layer of the skin and is a rare type of neuroendocrine tumor. These typically occur in the head and neck and are predominately found in older patients, or those with weakened immune systems.

Current treatments include surgery and chemotherapy agents--although Novartis ($NVS) is currently conducting a study of its marketed cancer drug Votrient to see if it too can help Merkel patients.

“As there are no approved treatments for second-line metastatic Merkel cell carcinoma and the standard of care is participating in clinical trials, these data represent a potential breakthrough for these patients,” Luciano Rossetti, head of research for Merck's biopharma business, told Reuters.

The drug was not tested against another medicine or placebo, but researchers concluded from an interim analysis that avelumab demonstrated "a manageable safety profile with durable responses."

In all, 6 patients (10%) experienced complete responses with no signs of cancer, while 12 others saw significant tumor shrinkage. The data will be presented at ASCO in Chicago next month, and could be used as a basis for seeking U.S. approval, according to the partners.

These data come just a day after Roche ($RHHBY) became the first drugmaker to bring a PD-L1 drug to the market with Tecentriq (atezolizumab) for bladder cancer. It follows on the success of Merck’s ($MRK) Keytruda and the market-leading Opdivo from Bristol-Myers Squibb ($BMY), which are both PD-1 inhibitors that treat melanoma and other oncology indications.

Keytruda has an advanced non-small cell lung cancer license for patients who express PD-L1, which was granted by the FDA last year, but is not itself a PD-L1 drug, with Opdivo also able to target the PD-L1 pathway. AstraZeneca ($AZN) is currently testing its PD-L1 candidate durvalumab in a number of cancers, as it will likely have to settle for second place in the PD-L1 market and fourth in the checkpoint inhibitor space, should it gain approval.

Pfizer, which has lagged behind its Big Pharma rivals in this therapy class, signed an $850 million deal with Germany’s Merck back in 2014 to gain access to its PD-L1 program. The two are also testing the drug in a host of other cancers, as well as joining them up with other meds from Pfizer’s pipeline and portfolio to see if a cocktail therapy can extend patients’ lives.

- check out the Reuters story