Merck's Keytruda tested in four new cancers

US drugmaker Merck &Co will present data on the use of its PD-1 inhibitor Keytruda in four new cancer types later this week as it jostles for territory in the fast-growing immuno-oncology sector.

Keytruda (pembrolizumab) is taking on Bristol-Myers Squibb's (BMS) rival drug Opdivo (nivolumab) head-to-head in some indications – notably melanoma and non-small cell lung cancer (NSCLC) – but both companies are also staking claims to other tumour types as the land grab rumbles on.

While both companies have dozens of trials running, they have different priorities for certain cancer types. BMS seems to be pressing ahead more strongly in renal cell carcinoma and gastric cancer, for example, while Merck (known as MSD outside the US) appears to be in front in bladder cancer.

At the European Cancer Congress (ECC) in Vienna, which gets underway on Friday (25 September), Merck will for the first time present data on Keytruda's potential in nasopharyngeal carcinoma, anal cancer, Merkel cell carcinoma and biliary tract cancer.

Nasopharyngeal carcinoma is a rare type of head and neck cancer, affecting around 240 people a year in the UK, while anal cancer is a little more common, with approximately 1,200 new cases a year.

Merkel cell carcinoma is a form of skin cancer that is very rare (an estimated 150 cases a year) but it is particularly aggressive and often spreads quickly to the lymph nodes, lungs, liver or bone. Finally, biliary tract cancer affects the cells lining the bile duct, with around 1,000 diagnoses a year.

Meanwhile, Merck will also make the case at the ECC that blocking the activity of both ligands that bind to the PD-1 receptor – PD-L1 and PD-L2 – could be the key to tumours responding to anti-PD-1 therapy.

Both Opdivo and Keytruda block the binding of both ligands, while other PD-1 inhibitors in development, including Roche's atezolizumab and AstraZeneca's durvalumab, have more activity against PD-L1.

"The initial data we are seeing with regard to PD-L2 expression now point to the potential relevance of dual PD-L1 and PD-L2 blockade in anti-PD-1 therapy for cancer treatment," said Dr Roger Dansey, who heads Merck's oncology late-stage development programme.

Merck will also present data from a trial looking at the combination of Keytruda (pembrolizumab) with Amgen's investigational oncolytic virus therapy talimogene laherparepvec in melanoma.