Deciphera Pharmaceuticals has secured approval from the US Food and Drug Administration (FDA) for its Qinlock (ripretinib) to treat fourth-line gastrointestinal stromal tumour (GIST).

The FDA approval allows Qinlock, a kinase inhibitor, to treat adult patients with advanced GIST who have secured prior treatment with three or more kinase inhibitors, including imatinib.

Earlier, the FDA granted breakthrough therapy and fast track designations, in addition to the priority review for Qinlock. The regulator also assessed the new drug application (NDA) under the real-time oncology review (RTOR) pilot programme.

The FDA approval was based on the efficacy data from the pivotal phase 3 INVICTUS study of Qinlock in patients with advanced GIS and combined safety data from INVICTUS and the phase 1 study of QINLOCK.

According to the company, the Qinlock showed a median progression-free survival of 6.3 months in INVICTUS study compared to 1.0 month in the placebo arm and significantly minimised the risk of disease progression or death by 85%.

The INVICTUS is a randomised, double-blind, placebo-controlled, international and multicenter clinical trial assessing the safety, tolerability, and efficacy of Qinlock compared to placebo in patients with advanced GIST whose previous therapies have included imatinib, sunitinib, and regorafenib

Deciphera randomised the patients in a 2:1 ratio to either 150mg of Qinlock or placebo once daily.

The progression-free survival (PFS) is the primary efficacy point of the trial, while the objective response rate (ORR) and overall survival (OS) are the secondary endpoints of the study.

Deciphera Pharmaceuticals president and CEO Steve Hoerter said: “The FDA approval of QINLOCK is an exciting milestone for people with GIST who have been waiting for a new treatment option designed specifically for their disease.

“I would like to thank the patients, their families and caregivers, and the healthcare professionals who made the QINLOCK clinical studies possible.

“With their contributions and the dedication of the team at Deciphera, we are delivering on our promise to provide important new medicines for the treatment of cancer.”

In September 2017, Deciphera announced that the FDA granted orphan drug designation to DCC-2618 pan-KIT and PDGFRα inhibitor to treat glioblastoma multiforme and anaplastic astrocytoma.