Glaxo Wins FDA Approval for Two Targeted Skin Cancer Drugs

GlaxoSmithKline Plc, the U.K.’s biggest drugmaker, won U.S. approval for two skin cancer drugs targeted at patients most likely to respond to the medications.

The Food and Drug Administration today approved Tafinlar and Mekinist for patients with melanoma, the most dangerous form of skin cancer, that has spread or can’t be surgically removed. The drugs are aimed at patients who have certain gene mutations that need to be detected using a diagnostic test made by Marcy L’Etoile, France-based BioMerieux, which the FDA also cleared.

About 77,000 Americans will be diagnosed with melanoma this year and 9,480 will die, the National Institutes of Health estimates. The FDA approved Roche Holding AG’s Zelboraf and Bristol-Myers Squibb Co.’s Yervoy for advanced or unresectable melanoma in 2011.

“Advancements in our understanding of the biological pathways of a disease have allowed for the development of Tafinlar and Mekinist,” Richard Pazdur, director of the FDA office that oversees oncology products, said in a statement.

The drugs from London-based Glaxo target patients who have certain BRAF gene mutations. About half of skin melanomas have a BRAF gene mutation, the FDA said.

Roche’s Zelboraf was approved with the first BRAF diagnostic test, made by the Basel, Switzerland-based company itself. Zelboraf generated $250 million in revenue last year for Roche, according to data compiled by Bloomberg.

Sales Estimates

Tafinlar may produce $279 million in sales in 2016 while Mekinist may generate $343 million, according to the average of eight analysts’ estimates compiled by Bloomberg. The drugs are among six new medicines Glaxo was counting on to gain U.S. regulatory approval this year.

Tafinlar and Mekinist are being approved separately though the treatments taken together delayed tumor progression 9.4 months compared with 5.8 months for patients taking Tafinlar alone, according data released last year by Glaxo. The company hasn’t submitted the combination data to the FDA, Melinda Stubbee, a Glaxo spokeswoman, said in an e-mail. Roche is also studying a similar combination.

Tafinlar, also known as dabrafenib, works by blocking BRAF, a mutant gene that spurs cancer-cell growth in about half of melanoma patients. Mekinist, known as trametinib, thwarts a related protein called MEK, which helps tumors resist an assault on BRAF.

The most serious side effects reported in patients who took Tafinlar in clinical trials included an increased risk of skin cancer, fevers complicated by low blood pressure and kidney failure. Those who took Mekinist reported serious side effects including heart failure and loss of vision.

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