Early Evidence Shows Gleevec-Xpovio Combo May Benefit Patients With Rare Form of Advanced Gastrointestinal Cancer

Treatment with the combination of Gleevec (imatinib) and Xpovio (selinexor) was safe and well tolerated in patients with advanced gastrointestinal stromal tumors, according to results of an early phase study.

The data, which were presented at the recent 2021 American Society of Clinical Oncology Annual Meeting, also demonstrated that the combination induced some effective responses in individuals with the rare gastrointestinal cancer after their disease progressed following treatment with at least Gleevec in the first-line setting.

Twelve patients (median age, 56.6 years) were enrolled in the phase 1b portion of the trial. All the patients received Gleevec at 400 milligrams (mg). Three patients received it in combination with Xpovio at 60 mg, another three received it with Xpovio at 80 mg and the remaining six received Xpovio at 100 mg.

The data demonstrated that most of the side effects patients in the study experienced were of mild to moderate severity. The most common mild to moderate side effects patients experienced included, but were not limited to, nausea (11 cases), vomiting (10 cases), fatigue (6 cases) and reduced appetite (6 cases). Some patients, however, experienced more severe or life-threatening side effects. Those cases included vomiting (1 patient), fatigue (2 patients), neutropenia (a low count of white blood cells, which may lead to infection) and anemia (1 patient each).

The instance of serious or severe vomiting was resolved after less than two weeks of a dose interruption.

The early phase results also showed that two patients achieved a partial response (decrease in the size of a tumor) to treatment, and that six patients achieved stable disease (cancer that is neither decreasing nor increasing in extent or severity). The study authors noted that the higher the dosage of Xpovio, the longer the duration of response to treatment.

Additionally, the combination was associated with a median progression-free survival (time during and after treatment when the patient lives without disease progression) of 3.5 months across the entire patient population.

“Which is more than what we know about placebo or even (Gleevec) rechallenge and more in line with other tyrosine-kinase inhibitors that have been tested in the field in single-arm treatments,” said Dr. Cèsar Serrano, from the Vall d’Hebron Institute of Oncology in Barcelona, Spain, during the presentation of the findings.

Serrano concluded his presentation of the data by noting that this was the first time that the combination of these two drugs induced clinical activity in this patient population. He added that the trial is still ongoing and that he and his colleagues are also studying the efficacy of Xpovio as a single agent in these patients.

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