[Updated, 11:04 am ET, see below] Deciphera Pharmaceuticals this morning announced plans to seek FDA approval of a cancer medicine that treats a deadly type of tumor that forms in the gastrointestinal tract.
The Deciphera (NASDASQ: DCPH) drug, ripretinib, hit its main goal in a Phase 3 trial, INVICTUS, in 129 patients with gastrointestinal stromal tumors (GIST) who have failed at least three treatments. Ripretinib kept tumors from spreading—what’s known as progression-free survival—for a median of 6.3 months (27.6 weeks), compared to a median of 1 month (4.1 weeks) for placebo patients. GIST patients on Deciphera’s drug were 85 percent less likely to die or see their disease progress than if they got a placebo.
Ripretinib failed to achieve one of its secondary goals: Only 9.4 percent of patients responded to treatment compared to none on placebo—the difference wasn’t statistically significant. Because it failed that goal, Deciphera can’t claim that the drug extended patients’ lives, even though it saw a “clinically meaningful” improvement by that measure: ripretinib patients lived for a median of 15.1 months, compared to 6.6 months for placebo patients.
The most common serious side effects tied to ripretinib were anemia, stomach pain, and high blood pressure. But hair loss, hand-foot syndrome, nausea, vomiting, muscle pain, and other side effects were also seen in patients taking the drug.
Waltham, MA-based Deceiphera will file for approval of ripretinib in the first quarter of 2020. It’ll disclose more details from the study at a future medical meeting.
Deciphera shares nearly doubled, to $39.84 apiece, in early trading on Tuesday.
GIST is a rare type of cancer that affects 4,000 to 6,000 US adults, typically those 60 and older, each year. The first option is surgery, but if the disease persists there are several targeted therapies known as kinase inhibitors available: imatinib (Gleevec), sunitinib (Sutent), and regorafenib (Stivarga).
Deciphera and rival Blueprint Medicines (NASDAQ: BPMC) are both trying to bring newer, similar kinase inhibitors into the mix. They have started by testing their drugs in patients who have failed Gleevec, Sutent, and Stivarga, and both have plans to move those drugs into earlier stages of testing.
Blueprint is currently ahead of Deciphera. The FDA just began a review of Blueprint’s drug avapritinib in fourth-line GIST, as well as a genetic subset of GIST patients. The agency is expected to make a decision by Feb. 14. But Deciphera has another Phase 3 study on the way, INTRIGUE, in which ripretinib must clear a much higher bar—it is going head to head against Sutent in GIST patients who have only failed one treatment. Last week, SVB Leerink analyst Andrew Berens noted that “most investors” were looking to see progression-free survival of at least 5.5 months in the INVICTUS study “to believe ripretinib will beat Sutent.” Deciphera cleared that bar.
[Updated with analyst comments.] The data “appear strongly supportive of benefit” for fourth-line GIST patients, surpass what ripetinib had shown in previous testing, and “at least partially de-risk” the head-to-head study against Sutent, which is the “larger and more commercially relevant opportunity,” Berens wrote in a research note on Tuesday. Still, Deciphera hasn’t said how many patients dropped out of the trial due to the drug’s side effects. That’s an important question to answer going forward, he wrote.