(Corrects paragraph one to show day of week Novartis said this was Monday, instead of Tuesday)
* Novartis to seek approval after July following trial
* Drug combo shrank tumours in 63 pct of patients in study
* Combination already approved in skin cancer
By John Miller
June 6 (Reuters) - A Novartis trial of two drugs against an aggressive lung cancer bodes well for broadening their use beyond melanoma, the Swiss drugmaker told the American Society of Clinical Oncology's conference in Chicago on Monday.
Novartis's Tafinlar and Mekinist combination shrank tumours in 63 percent of the trial's 57 people with BRAF V600E-mutation positive non-small cell lung cancer who had failed on chemotherapy, the company said, citing a Phase II study.
The company already has U.S. Food and Drug Administration and European approvals for the drugs against BRAF V600E-mutation positive melanoma.
It is now aiming for a U.S. regulatory submission for lung cancer after July, Alessandro Riva, global head of Novartis Oncology Development, said in an interview.
Rare-but-deadly BRAF V600E-mutation positive lung cancer is marked by a gene change that helps it grow, making fighting it difficult with chemotherapy. In the study, the median progression-free survival was 9.7 months, which Riva called unprecedented.
The latest findings follow those from an interim analysis of 24 patients in 2015 that showed similar results.
"We are talking about a response rate that is in the 60 percent ballpark, (with) progression-free survival that is approaching 10 months -- never seen in the past with chemotherapy", Riva said. "Chemotherapy... has a progression-free survival (PFS) that is not more than two or three months."
The median analyst estimate for 2018 sales for both drugs is about $1.3 billion, according to Reuters data.
Late last year, Novartis's cross-town rival Roche also won approval for its own BRAF V600 melanoma combination, Zelboraf and Cotellic.
With this lung cancer study, Novartis is now seeking to expand its combination's uses, in part to differentiate itself from Roche's offering.
Doctors leading Novartis's study said it confirms a potential new avenue to take on an aggressive lung cancer, whose patients have a poor prognosis.
"The potential to treat this oncogene gives hope to a very small, underserved patient population," said Dr. David Planchard, a thoracic oncology specialist at France's Cancer Institute Gustave-Roussy and the trial's principal investigator.
The most common side effects were fever, nausea, vomiting, diarrhoea, abnormal physical weakness, decreased appetite, dry skin, chills, accumulation of fluids causing swelling, cough and rash.
During the study, 23 of the 57 participants died.
Novartis acquired the drugs after buying GlaxoSmithKline's oncology business last year. [reut.rs/1Y2n8fB ] (Editing by Alexander Smith)