Merck's Keytruda granted breakthrough status in lung cancer

Merck's newly launched immunotherapy treatment Keytruda has just been granted special fast-track status for use in non-small cell lung cancer (NSCLC).

Keytruda (pembrolizumab) is the first of a new generation of PD-1 and PD-L1 immunotherapy treatments to gain US approval, and was launched in September in its first indication, for patients with advanced melanoma.

The FDA gave it special Breakthrough Designation Therapy status for melanoma, and has now followed suit for NSCLC. Lung cancer is the leading cause of all cancer deaths in the US, and each year kills more people than colon, breast and prostate cancers combined. NSCLC is the most common form of the disease (representing 85-90% of cases), but existing treatments have failed to extend lives of sufferers significantly.

Now the US regulator has granted Breakthrough Therapy Designation to Keytruda for patients who have neither of two genetic mutations – those who are Epidermal Growth Factor Receptor (EGFR) mutation-negative, and Anaplastic Lymphoma Kinase (ALK) rearrangement-negative non-small cell lung cancer (NSCLC) whose disease has progressed on or following platinum-based chemotherapy.

Patients who are EGFR mutation positive or who are ALK mutation positive are currently served by drugs which target these mutations. In the case of EGFR mutations, these are AstraZeneca's Iressa and Roche's Tarceva, and in ALK, Pfizer's Xalkori and Novartis' Zykadia.

However, only a minority of NSCLC patients have these mutations – between 10-30 per cent being EGFR positive, and only approximately three per cent being ALK positive.

Merck is targeting the larger group of NSCLC patients who won't benefit from these existing drugs. These patients have had no new drugs launched for them in recent years, and consequently the prognosis in this cohort remains bleak.

"The FDA's Breakthrough Therapy Designation of Keytruda underscores that new treatment approaches for advanced non-small cell lung cancer continue to be needed," said Dr. Roger Perlmutter, president, Merck Research Laboratories. "Our data investigating the use of Keytruda in this difficult-to-treat malignancy are very encouraging, and we look forward to working closely with the FDA to expedite our clinical programme."

Many other companies are investigating the potential of immunotherapies against lung cancer, including Merck's closest rivals in the PD-1/PD-L1 field, including BMS, whose Opdivo is close to approval in NSCLC, as well as AstraZeneca and Roche.