(P 117) SHOULD REGORAFENIB BE PRESCRIBED AS A CONTINUOUS SCHEDULE AT LEAST IN GASTROINTESTINAL STROMAL TUMORS (GIST)?

Objective: The aim of the present analysis is to describe our Institution experience about the feasibility of continuous administration of Regorafenib (Rego) as an efficacious regimen with a well-manageable toxicity in advanced GIST patients.

Methods: We retrospectively collected clinical, pathological, and radiological data of patients with GIST treated with continuous Rego 120 mg/die at the Humanitas Research Hospital, from May 2021 to June 2022. The rationale to switch to a continuous administration came from the experience with Imatinib and Sunitinib: the continuous administration in GIST, based on their peculiar biology, allows a steady suppression of the oncogenic pathways avoiding the drug resistance and reducing the disease progression. Moreover, continuous administration of Rego at the dose 120 mg/day warrants the recommended Rego dose intensity, with a manageable toxicity profile.

Results: We identified three patients treated with continuous Rego. For these patients, the mean follow-up since the start of Rego was 16.4 months (range 9.5 – 20.3 months). Patients’ characteristics are summarized in Table 1. All three of them had started a standard schedule of Rego in third line as per guidelines. The reasons for switching to continuous schedule were: symptoms exacerbation during the week-off treatment in the first patient, a serious adverse event (G3 anemia) in the second patient and both reasons in the third. After the switch to continuous schedule, none of the patients reported serious adverse events, achieving a better control of the tumor-related symptoms. One of the patients experienced disease progression after 17 months of Rego (of which 9 months of continuous schedule); the other two patients are still receiving continuous Rego, with a progression-free survival of 19.3 (6 after the start continuous schedule) and 9.5 months (6.2 after the start of continuous schedule) respectively.

Conclusion: In our experience, continuous schedule Rego showed a similar efficacy compared to literature data of the intermittent schedule in patients with GIST, with a favorable toxicity profile. The experience with these three patients suggests continuous schedule of Rego as a valid alternative, also for frail patients. Further prospective analyses are needed.

Abstract CTOS regorafenib continuous schedule Table 1.pdf