The FDA ( U.S. Food and Drug Administration ) has approved Qinlock ( Ripretinib ) tablets as the first new drug specifically approved as a fourth-line treatment for advanced gastrointestinal stromal tumor ( GIST ), a type of tumor that originates in the gastrointestinal tract.
Qinlock is indicated for adult patients who have received prior treatment with three or more kinase inhibitor therapies, including Imatinib.
Despite the progress that has been made over the past 20 years in developing treatments for GIST, including four FDA-approved targeted therapies – Imatinib in 2002, Sunitinib in 2006, Regorafenib in 2013 and Avapritinib in 2020 – some patients don’t respond to treatment and their tumors continues to progress.
Each year, approximately 4,000 to 6,000 adults in the United States are diagnosed with a GIST.
GISTs arise when abnormal cells form in the tissues of the gastrointestinal tract. GISTs most commonly occur in the stomach, small intestine, and large intestine but can start anywhere along the gastrointestinal tract.
Ripretinib is a kinase inhibitor, meaning it works by blocking a type of enzyme called a kinase, which helps keep the cancer cells from growing.
Qinlock’s approval was based on the results of an international, multi-center, randomized, double-blind, placebo-controlled clinical trial that enrolled 129 patients with advanced GIST who had received prior treatment with other FDA-approved targeted therapies, Imatinib, Sunitinib and Regorafenib.
The trial compared patients who were randomized to receive Ripretinib to patients who were randomized to receive placebo, to determine whether progression free survival ( PFS ) – the time from initial treatment in the clinical trial to growth of the cancer or death – was longer in the Ripretinib group compared to the placebo group.
During treatment in the trial, patients received Ripretinib or placebo once a day in 28-day cycles, repeated until tumor growth was found ( disease progression ), or the patient experienced intolerable side effects.
After disease progression, patients who were randomized to placebo were given the option of switching to Ripretinib.
On average, the PFS rate in patients in the Ripretinib group was 6.3 months, compared to one month for patients in the placebo group.
The most common side effects with Ripretinib were alopecia, fatigue, nausea, abdominal pain, constipation, myalgia, diarrhea, decreased appetite, palmar-plantar erythrodysesthesia syndrome and vomiting.
Ripretinib can also cause serious side effects including skin cancer, hypertension and cardiac dysfunction manifested as ejection fraction decrease.
Qinlock may cause harm to a developing fetus or a newborn baby. Health care professionals should advise pregnant women of this risk and should advise both females of reproductive potential and male patients with female partners of reproductive potential, to use effective contraception during treatment and for one week after the last dose.
Patients should be advised not to breastfeed while taking Qinlock. ( Xagena )
Source: FDA, 2020