(Reuters) – U.S. regulators on Friday approved Qiagen NV’s gene test to identify those colorectal cancer patients most likely to benefit from Erbitux (cetuximab, Bristol-Myers Squibb and Eli Lilly), Qiagen said.
The test could pave the way for greater use of Erbitux, sales of which have been crimped by reluctance of some doctors to prescribe the drug until a long-awaited companion diagnostic was approved to pinpoint patients that would best respond to the medicine.
An estimated 40% of patients with colorectal cancer have mutated forms of the K-ras gene, which make them poor candidates for Erbitux. About 60% of patients have non-mutated forms of K-ras and stand a good chance of benefiting from the drug introduced in 2004 for colon cancer.
The U.S. Food and Drug Administration in 2009 approved new language in the labels of Erbitux and Amgen Inc’s similar colon cancer drug, Vectibix (panitumumab), saying they won’t work for those with mutated forms of K-ras.
About 110,000 U.S. colorectal cancer patients could benefit from K-ras gene testing each year, according to Qiagen.
Companion diagnosis is a promising new trend in oncology, making it increasingly common to test tumor tissue for certain genes or gene mutations to determine the best treatment. This reduces the size of a drug’s potential target population but helps drugmakers fetch higher prices per treatment because the approach leads to better effectiveness.
A Qiagen spokesman said the K-ras test could generate peak annual sales of about $20 million. Companion diagnostics accounted for $75 million of the German company’s sales last year, including test kits and related lab automation gear sold in Europe and Japan.
The diagnostics are one of its fastest growing categories.
Qiagen is hoping to win its next FDA approval for a test to go with Vectibix. It also aims to seek U.S. approval for a test to accompany privately held Boehringer Ingelheim’s lung cancer drug afatinib.