Optimal Avapritinib Treatment Strategies for Patients with Metastatic or Unresectable Gastrointestinal Stromal Tumors.

BACKGROUND: Avapritinib, a novel inhibitor of KIT/PDGFRA, is approved in the U.S. for the treatment of adults with PDGFRA exon 18-mutant unresectable or metastatic gastrointestinal stromal tumors (U/M GISTs). We assessed the safety of avapritinib and provide evidence-based guidance on management of avapritinib-associated adverse events (AEs), including cognitive effects and intracranial bleeding. MATERIALS AND METHODS: We performed a post hoc analysis of data from a two-part, single-arm dose escalation/expansion phase I study (NAVIGATOR; NCT02508532) in patients with U/M GISTs treated with oral avapritinib 30-600 mg once daily. The primary endpoints were safety and tolerability; the impact of dose modification (interruption and/or reduction) on progression-free survival (PFS) was a secondary endpoint. Efficacy analyses were limited to patients who started avapritinib at 300 mg (approved dose). RESULTS: Of 250 patients enrolled in the study, 74.0% presented with KIT mutation and 24.8% presented with PDGFRA exon 18-mutation; 66.8% started avapritinib at 300 mg. The most common treatment-related AEs (any grade) were nausea (59.2%), fatigue (50.0%), periorbital edema (42.0%), anemia (39.2%), diarrhea (36.0%), vomiting (36.0%), and increased lacrimation (30.8%). No treatment-related deaths occurred. Among 167 patients starting on 300 mg avapritinib, all-cause cognitive effects rate (grade 1-2) was 37.0% in all patients and 52.0% in patients ≥65 years. Cognitive effects improved to a lower grade more quickly with dose modification (1.3-3.1 weeks) than without (4.9-7.6 weeks). Median PFS was 11.4 months with dose modification and 7.2 months without. CONCLUSION: Tolerability-guided dose modification of avapritinib is an effective strategy for managing AEs in patients with GISTs. IMPLICATIONS FOR PRACTICE: Early recognition of adverse events and tailored dose modification appear to be effective approaches for managing treatment-related adverse events and maintaining patients on avapritinib. Dose reduction does not appear to result in reduced efficacy. Patients' cognitive function should be assessed at baseline and monitored carefully throughout treatment with avapritinib for the onset of cognitive adverse events. Dose interruption is recommended at the first sign of any cognitive effect, including grade 1 events.

Lack of association between polymorphisms of the toll-like receptor 4 gene and cerebral ischemia.

Toll-like receptor-4 (TLR4), an important mediator of the innate immune response, is expressed in atherosclerotic lesions. The common single nucleotide exchange (Asp299Gly) of the TLR4 gene has been previously reported to impair TLR4 function and to be associated with a decreased risk of carotid atherosclerosis. Therefore, we aimed to detect the potential impact of TLR4 genotypes on the risk of cerebral ischemia. We studied the prevalence of two common polymorphisms of the TLR4 gene (Asp299Gly and Thr399Ile) in 3 independent study populations: (1.) in a cross-sectional study including 769 patients either with type 1 or type 2 diabetes mellitus, of whom 56 (7.2%) had a history of cerebral ischemia (study 1), (2.) a case-control study (study 2) including 128 consecutive patients with cerebral ischemia, mean age 60 +/- 10.9 years and 139 control subjects, and (3.) a case-control study (study 3) including 171 young adults aged < 50 years with cerebral ischemia and 204 control individuals. In all subjects, Asp299Gly and Thr399Ile were detected by restriction length analysis. The prevalence of the TLR4 genotypes was essentially the same between patients with cerebral ischemia and control subjects in all 3 study populations. Furthermore, there was also no association with the subgroup of atherosclerotic stroke in both case-control studies populations. Although TLR4 polymorphisms are associated with a decreased risk of carotid atherosclerotic lesions, our findings indicate that they do not influence the prevalence of cerebral ischemia. This implies that the Asp299Gly TLR4-allele might have a protective role in carotid atherosclerosis, but not in cerebral ischemia.