Dataset Information

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.

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 .

SUBMITTER: von Mehren M

PROVIDER: S-EPMC7976710 | biostudies-literature | 2021 Mar

REPOSITORIES: biostudies-literature

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Publications

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.

von Mehren Margaret M Heinrich Michael C MC Shi Hongliang H Iannazzo Sergio S Mankoski Raymond R Dimitrijević Saša S Hoehn Gerard G Chiroli Silvia S George Suzanne S

BMC cancer 20210319 1

<h4>Background</h4>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).<h4>Methods</h4>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- ...[more]

PMID: 33740926

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Project description:ImportanceThe D842V platelet-derived growth factor receptor α (PDGFRA) mutation identifies a molecular subgroup of gastrointestinal stromal tumors (GISTs), primarily resistant to standard tyrosine kinase inhibitors and with an overall more indolent behavior. Although functional imaging with 18F-fluorodeoxyglucose-labeled positron emission tomography ([18F]FDG-PET) plays a proven role in GISTs, especially in early assessment of tumor response, less is known about [18F]FDG uptake according to the GIST molecular subtypes.ObjectiveTo evaluate the degree of [18F]FDG uptake in PDGFRA-mutant GISTs and better define the role of functional imaging in this rare and peculiar subset of GISTs.Design, setting, and participantsThis multi-institutional retrospective cohort study involving 7 GIST reference centers in Italy included patients with PDGFRA-mutant GIST who underwent [18F]FDG-PET from January 1, 2000, to December 31, 2023. Data on the maximum standardized uptake value (SUVmax) of primary tumor or metastatic disease were collected.ExposurePDGFRA-mutant GIST and [18F]FDG-PET.Main outcome and measureThe primary outcome was the degree of [18F]FDG uptake of PDGFRA-mutant GISTs, with a focus on the D842V-mutant subgroup. Secondary objectives were to assess the association between the degree of [18F]FDG uptake and main clinicopathologic features.ResultsA total of 71 patients with PDGFRA-mutant GISTs were included in the analysis: 37 (52.1%) in the D842V subgroup (group A) and 34 (47.9%) in the non-D842V subgroup (group B). Additionally, 70 patients with KIT exon 11-mutant GIST served as a control group (group C). For all 141 participants, the median age at diagnosis was 59 (range, 26-89) years, and 81 patients (57.4%) were male. Overall, the median SUVmax was 4.4 (IQR, 0-10.1), while the median SUVmax for group A was 0 (IQR, 0-3.2); for group B, 3.6 (IQR, 0-5.1); and for group C, 10.1 (IQR, 5.1-13.9). The median SUVmax of PDGFRA-mutant GISTs was significantly lower than the median value of KIT exon 11-mutant GISTs (0 [IQR, 0-4.3] vs 10.1 [IQR, 5.1-14.0]; P < .001). Median [18F]FDG uptake was significantly lower in the D842V subgroup compared with the non-D842V subgroup (0 [IQR, 0-3.2] vs 3.6 [IQR, 0-5.1]; P = .02). Moreover, the triad of gastric primary tumor, tumor size greater than 10 cm, and SUVmax of 5.75 or less was associated with identification of PDGFRA-mutant GISTs.Conclusions and relevanceIn this cohort study of patients with PDGFRA-mutant GISTs, the D842V-mutant GISTs were associated with an overall lower [18F]FDG uptake compared with other GIST subgroups. Therefore, the role of functional imaging with [18F]FDG-PET in this subset of GISTs may be limited and should be further explored for its potential prognostic and predictive value.

Project description:BackgroundAvapritinib, 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 methodsWe 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).ResultsOf 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.ConclusionTolerability-guided dose modification of avapritinib is an effective strategy for managing AEs in patients with GISTs.Implications for practiceEarly 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.

Project description:BackgroundGastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumors of the gastrointestinal tract. Recent advent of tyrosine kinase inhibitors (TKIs) has significantly improved the prognosis of GIST patients. However, responses to TKI therapy can vary depending on the specific gene mutation. D842V, which is the most common mutation in platelet-derived growth factor receptor alpha exon 18, shows no response to imatinib and sunitinib. Radiomics features based on venous-phase contrast-enhanced computed tomography (CECT) have shown potential in non-invasive prediction of GIST genotypes. This study sought to determine whether radiomics features could help distinguish GISTs with D842V mutations.MethodsA total of 872 pathologically confirmed GIST patients with CECT data available from three independent centers were included and divided into the training cohort ( n=487 ) and the external validation cohort ( n=385 ). Clinical features including age, sex, tumor size and location were collected. Radiomics features on the largest axial image of venous-phase CECT were analyzed and a total of two radiomics features were selected after feature selection. Random forest models trained on non-radiomics features only (the non-radiomics model) and on both non-radiomics and radiomics features (the combined model) were compared.ResultsThe combined model showed better average precision (0.250 vs. 0.102, p = 0.039) and F1 score (0.253 vs. 0.155, p = 0.012) than the non-radiomics model. There was no significant difference in ROC-AUC (0.728 vs. 0.737, p = 0.836) and geometric mean (0.737 vs. 0.681, p = 0.352).ConclusionsThis study demonstrated the potential of radiomics features based on venous-phase CECT images to identify D842V mutation in GISTs. Our model may provide an alternative approach to guide TKI therapy for patients inaccessible to sequence variant testing, potentially improving treatment outcomes for GIST patients especially in resource-limited settings.

Dataset Information

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.

Background

Methods

Results

Conclusions

Trial registration

Publications

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.

Similar Datasets

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