Clinical efficacy comparison of avapritinib with other tyrosine kinase inhibitors in gastrointestinal stromal tumors with PDGFRA D842V mutation: a retrospective analysis of clinical trial and real-world data

Margaret von Mehren, Michael C. Heinrich, Hongliang Shi, Sergio Iannazzo, Raymond Mankoski, Saša Dimitrijević, Gerard Hoehn, Silvia Chiroli, Suzanne George

Research output: Contribution to journalArticlepeer-review

14 Scopus citations

Abstract

Background: Avapritinib, a potent inhibitor of KIT and platelet-derived growth factor receptor A (PDGFRA) tyrosine kinases, has demonstrated unprecedented clinical activity in PDGFRA D842V-mutant gastrointestinal stromal tumors (GIST). Methods: This retrospective analysis compared efficacy of avapritinib in patients enrolled in the NAVIGATOR phase 1 trial (NCT02508532) with the efficacy of other tyrosine kinase inhibitors (TKIs) in patients with unresectable/metastatic PDGFRA D842V-mutant GIST enrolled in a retrospective natural history study (Study 1002). The primary endpoint was overall survival (OS) from the start of reference treatment (avapritinib for NAVIGATOR patients or first-line TKI for treatment of unresectable/metastatic GIST for Study 1002 patients); the secondary endpoint was progression-free survival (PFS). Adjusted Kaplan–Meier survival curves were compared by Cox regression. Results: Fifty-six (NAVIGATOR) and 19 (Study 1002) patients with PDGFRA D842V-mutant GIST were evaluated; of the 56 patients from NAVIGATOR, a subgroup of patients treated with either 300 mg (recommended phase 2 dose) or 400 mg (maximum tolerated dose) avapritinib starting dose (n = 38) were analyzed separately. Patient characteristics were adjusted for imbalances by propensity score between the study groups. Inverse probability of treatment weighting-adjusted Kaplan–Meier analysis of OS showed median OS was not reached for NAVIGATOR patients treated with any of the avapritinib doses tested and was 12.6 months for Study 1002 patients; OS rate at 6/48 months was 100%/63% in NAVIGATOR and 56%/17% in Study 1002 (P = 0.0001). In the 300/400 mg subgroup, adjusted OS rates at 6/36 months were 100%/73 and 68%/20% in Study 1002 (P = 0.0016). Adjusted median PFS was 29.5 months in NAVIGATOR and 3.4 months in Study 1002. Conclusions: In this indirect, retrospective analysis, avapritinib demonstrated more durable survival outcomes compared with other TKIs in patients with unresectable/metastatic PDGFRA D842V-mutant GIST. Trial registration: The NAVIGATOR trial was registered at ClinicalTrials.gov as per July 2015, Identifier: NCT02508532.

Original languageEnglish
Article number291
Pages (from-to)291
JournalBMC Cancer
Volume21
Issue number1
DOIs
StatePublished - Feb 19 2021

Keywords

  • Clinical Trials, Phase I as Topic
  • Female
  • Gastrointestinal Stromal Tumors/drug therapy
  • Humans
  • Kaplan-Meier Estimate
  • Male
  • Middle Aged
  • Progression-Free Survival
  • Protein Kinase Inhibitors/administration & dosage
  • Pyrazoles/administration & dosage
  • Pyrroles/administration & dosage
  • Receptor, Platelet-Derived Growth Factor alpha/antagonists & inhibitors
  • Retrospective Studies
  • Triazines/administration & dosage

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