In the battle of Kit/PDGFRα kinase inhibitors for gastrointestinal stromal tumours Blueprint grabbed an early lead over Deciphera, but the tables were turned after a study setback. On Friday Deciphera completed its rout, with its ripretinib, now trademarked Qinlock, securing a fourth-line GIST label thanks to the Invictus trial. Not only did this US nod come three months before the FDA’s action date, but on the same day that Blueprint’s Ayvakit, which had failed its Voyager trial, was slapped with a highly predictable complete response letter. The question now is how big each drug can become: true, Qinlock has an all-comers label, but its real potential is in earlier lines of GIST therapy. Ayvakit in GISTs looks to be limited to a niche of patients harbouring the PDGFRα exon 18 mutation, including D842V mutations, and Blueprint aims to seek approval beyond the US and separately in systemic mastocytosis. Qinlock’s second-line GIST study, Intrigue, should complete enrolment in the second half of this year, and read out its primary PFS endpoint next year. Ayvakit’s Pathfinder trial in systemic mastocytosis was to have yielded data in the first quarter, but its timeline has slipped by six months.
|The duelling Kit/PDGFRα kinase inhibitors|
|Company||Drug||First US approval||Approved indication||2026e sales ($m)|
|Deciphera||Qinlock||15 May 2020||4th-line GISTs||1,290|
|Blueprint||Ayvakit||9 Jan 2020||GISTs harbouring a PDGFRα exon 18 mutation, incl D842V||1,119*|
|Source: EvaluatePharma sellside consensus; *forecast precedes 15 May complete response letter; GIST=gastrointestinal stromal tumour.|