Novartis hit with patent claim over melanoma treatment

Novartis has been hit with a patent infringement lawsuit by Plexxikon, a drug-discovery company.

On Thursday, August 2 in a filing at the US District Court for the Northern District of California, Plexxikon accused Novartis of infringing US patent number 9,469,640.

The patent, called “Compounds and methods for kinase modulation”, covers a class of selective BRAF kinase inhibitors which selectively bind to the BRAF kinase that results from the V600E mutation.

The BRAF gene provides instructions for making a protein that helps transmit chemical signals from outside the cell to the cell's nucleus, according to the US National Library of Medicine.

Plexxikon said that in 2005, its scientists discovered and started making compounds that reduce the growth of cancer cells that have a mutated form of the BRAF gene.

“The BRAF gene encodes information used by cells to produce enzymes (called ‘BRAF kinases’) that increase cellular metabolism and growth,” said the claim.

The mutated BRAF gene “substantially increases” BRAF kinase activity, which drives the proliferation of cancer cells.

“Although BRAF kinase inhibitors existed prior to Plexxikon’s discoveries, those BRAF kinase inhibitors were not selective and therefore inhibited many different BRAF kinases,” said the claim.

Plexxikon licensed vemurafenib (a selective BRAF kinase inhibitor it had developed) to its development partner and began clinical trials in 2006.

In 2011, the Food and Drug Administration (FDA) granted approval for the drug for the treatment of patients with “unresectable or metastatic melanoma with BRAFV600E mutation as detected by an FDA-approved test”.

Plexxikon’s development partner then began selling vemurafenib under the trademark Zelboraf.

Dabrafenib, one of the molecules within the class covered by the patent, was brought to market by Novartis’s predecessor in interest, GSK, said the suit.

“In 2013, GSK received FDA approval to sell dabrafenib for treatment of melanoma and began selling it under the trademark Tafinlar. Tafinlar directly competes with Plexxikon’s Zelboraf,” alleged Plexxikon.

In 2015, GSK transferred a portfolio of oncology drugs, including Tafinlar, to Novartis.

Plexxikon said that it had approached GSK back in 2005, disclosing the genetic target of Plexxikon’s selective kinase inhibitors, and offering to engage in a dialogue about possible collaboration.

The companies entered into a confidential disclosure agreement but could not reach a business arrangement.

“In short, there is substantial evidence to suggest that GSK built dabrafenib by copying Plexxikon’s invention,” said Plexxikon.

The drug discovery company is seeking injunctive relief, triple damages, royalties, attorneys’ fees, costs, and a jury trial.

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