Session VI: Rare GI Tumors: NETs, GISTs, and Anal cancer
SO-12: Updated safety, efficacy and PK results from an open-label, multicenter, phase I/II study of avapritinib in Chinese patients with unresectable or metastatic gastrointestinal stromal tumors (GIST)
The study authors conclude that avapritinib - a potent, selective, small-molecule, KIT/PDGFRA inhibitor - appears generally well-tolerated at 200 mg and 300 mg QD in Chinese patients. 300 mg QD was determined as RP2D for Chinese patients. Their data show that avapritinib demonstrated strong antitumor activity in patients with PDGFRA D842V- mutant and 4L+ GIST, making it an important potential new treatment option for the population.
The study authors conclude that median overall survival was 11.7 months longer with 177Lu-DOTATATE 7.4 GBq (200 mCi) compared to high-dose octreotide in the NETTER-1 trial (48 vs. 36.3 months). This difference was not statistically significant, potentially impacted by a high rate (36%) of cross-over of patients in the control arm to radioligand therapy after progression. This study demonstrated a clinically and statistically significant improvement in progression-free survival as a primary endpoint (HR: 0.18, p < 0.0001) as well as a clinically meaningful trend towards improvement in median overall survival in 177Lu-DOTATATE treatment arm. There were no new safety signals observed during the median 6.3-year long-term follow-up.