Merck KGaA's prospective lung cancer treatment tepotinib became the third drug against a rare and aggressive sub-type of the disease that won U.S. Food and Drug Administration's breakthrough therapy designation. Novartis last week won the breakthrough therapy tag, which puts it on a fast track for regulatory review, for its capmatinib drug. Pfizer's Xalkori drug was given the designation. All three medicines are designed to tackle the so-called MET exon14 skipping mutation in the genetic makeup of a lung tumour, which accounts for 3% to 5% of all non-small cell lung (NSCLC) cancer cases. Germany's Merck KGaA, which in February struck a large collaboration deal over cancer immunotherapy bintrafusp alfa with GSK, reiterated on Wednesday that it would develop tepotinib under its own steam.