Roche unit Chugai Pharmaceutical has filed for approval of its candidate non-small cell lung cancer drug erlotinib in Japan.

Erlotinib, licensed from OSI Pharmaceuticals of the USA, is the only epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor which has shown a survival benefit in patients with NSCLC.

Erlotinib is already approved as Tarceva in more than 50 countries around the world, including the USA and Europe, by Roche/Genentech, and last week the latter reported that first-quarter sales of the drug almost doubled to $93 million. In November its indications in the USA were extended to include the treatment of pancreatic cancer.

Drugs such as Tarceva and another EGFR inhibitor, AstraZeneca’s Iressa (gefitinib), are currently used to treat NSCLC patients who have failed one or more chemotherapy regimens, representing around 30% of total NSCLC cases.

A Phase II study conducted specifically to evaluate erlotinib's efficacy and safety in Japanese patients has been completed. The results confirmed erlotinib's anti-tumor effect and tolerability in patients after failure of prior chemotherapy regimen including platinum treatment.

There were approximately 85,000 cases of lung cancer in Japan last year, according to Chugai.

"We expect Japan to be among the top countries in terms of sales potential for Tarceva, and to be a key growth driver for this product," said Gabriel Leung, president of OSI's cancer drugs division, in a statement.