Deciphera misses blockbuster opportunity as Qinlock fails to top Pfizer's Sutent in rare stomach cancer

Last May, Deciphera Pharmaceuticals’ Qinlock became the first drug the FDA specifically approved for heavily pretreated patients with gastrointestinal stromal tumor. But now, a trial flop has squashed the company’s hope to move up in the treatment sequence, nixing a blockbuster opportunity.

Qinlock failed to top Pfizer’s Sutent at staving off tumor progression or death in gastrointestinal stromal tumor (GIST) patients previously treated with Novartis’ Gleevec. The bad news wiped over 70% off Deciphera’s stock price on Nasdaq Friday morning.

Deciphera investors have every reason to be disappointed. Failure of the phase 3 Intrigue trial marks a serious blow to Deciphera as a big part of the company’s value rested on its outcome.

If the trial were successful, the second-line KIT mutation-driven GIST indication could have added $1.37 billion to Qinlock's peak sales estimate, SVB Leerink Andrew Berens wrote in a Tuesday note to clients. The indication’s risk-adjusted value, at $2.33 billion, represented 58% of Deciphera’s total value in Berens’ calculation. By comparison, Qinlock’s current fourth-line indication only bears a peak sales potential of $81 million, per Berens.

RELATED: Deciphera fills in where Blueprint falls short with early FDA nod in rare stomach cancer

During the third quarter, Qinlock brought in sales of just $21.7 million, a 1.6% decrease from the second quarter despite a 5% price increase in July, Berens noted.

Physicians sometimes use a drug off-label in earlier lines of treatment if they have enough confidence in the med’s efficacy. But that didn’t seem to happen with Qinlock.

“In the U.S., Qinlock sales appear to have plateaued in 4L, with management indicating that duration of usage patterns appear similar to” Qinlock’s profession-free survival performance in its phase 3 Invictus trial, Berens said.

From the current Intrigue study, second-line GIST patients with a KIT exon 11 mutation who got Qinlock lived a median 8.3 months without disease progression, versus seven months for the Sutent group. That translated into a small reduction of 12% for the risk of tumor progression or death. In the broader trial population, the median progression-free survival lengths were 8 months and 8.3 months for Qinlock and Sutent, respectively.