Investigators sought to undertake a real-world assessment of sunitinib use in the treatment of GIST patients as well as contemporary outcomes.

Among 123 adult patients across 20 Spanish institutions between February 2018-June 2019, 109 patients were eligible for observational and retrospective analysis. Demographic, clinicopathological and molecular, and toxicity data was collected and correlated with outcomes.

Logistic regression models were utilized in order to identify predictive factors for PFS and OS. Statistically significant variables in the univariate analysis were further studied via multivariate Cox proportional hazards model.

As a result,  109 patients, with a median age of 62 years, received sunitinib at schedule per treating physician’s choice: 37.5 mg QD (45%), 50 mg QD 4/2 (36%), other (19%). 43% of patients had been treated previously with high-dose imatinib previously (600-800mg/day). Mutational status was available in 75 patients (69%). For the cohort’s entirety, the mPFS was 12.2 months, with a mOS of 105 months. PFS increased in KIT exon 9 mutations and wild-type vs exon 11 (25.1 months, 12.2 months v. 10.4 months respectively, p=0.760). No differences in outcomes regarding the type of institution (referral center v. community-based) were identified. The best response during the treatment was stable disease (46%) followed by partial response (32%). Most common toxicities included asthenia, hand-foot-skin reaction and hypertension.

Moreover, patients were identified by two groups: refractory (progression ≤3 months) and long-term responders (progression >8 months). PFS in the latter group was significantly superior, 25.3 months. In the univariant analysis, the following factors predicted a longer PFS in GIST patients treated with sunitinib: peritoneal metastases, low number of metastases, hypothyroidism, decreased neutrophil count, sunitinib dose reduction and partial/complete response. In the multivariate analysis, the following factors predicted better PFS: partial/complete response, decreased neutrophil count and sunitinib dose reduction.

In conclusion, data study results confirm that sunitinib is found as an effective and safe option for the treatment of imatinib-resistant, advanced GIST patients.

“GIST patients in this study displayed a more durable PFS compared to prior studies and the pivotal trial, underscoring a group of long-term responders that particularly benefit from sunitinib therapy. This will be further characterized in the future. Finally, this analysis offers a contemporary benchmark for PFS and outcomes among metastatic GIST patients treated in the second line for metastatic disease,” states César Serrano, MD, PhD, alongside co-investigators. -Alexis Hyams