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Pediatric and AYA Sarcomas

(P 255) AN OPEN-LABEL, TWO-COHORT, PHASE 1A/B STUDY OF WEEKLY IRINOTECAN HYDROCHLORIDE LIPOSOME INJECTION COMBINED WITH VINCRISTINE AND TEMOZOLOMIDE (NALIRI-VT) IN PATIENTS WITH ADVANCED EWING SARCOMA

    Author(s)

  • Jie XU, MD

    Beijing
    Peking University People's Hospital
    Beijing, Beijing, China (People's Republic)

Objective: To determine the recommended phase II dose (RP2D), safety, and preliminary efficacy of weekly liposomal irinotecan combined with vincristine and temozolomide (NALIRI-VT) in relapsed/refractory Ewing sarcoma in both children and adults.

Methods: This was an open-label, non-randomized, two-cohort, 2-part phase Ia/b study enrolling patients with relapsed or refractory Ewing sarcoma. Children and adults were enrolled in two cohorts (Cohort A and Cohort B) respectively. A starting dose of 25mg/m2 (level 1) NALIRI weekly infusion was initiated in the escalation phase, utilizing a 3+3 design with the following dose levels of 30mg/m2, 35mg/m2 and 40mg/m2 (level 2-4). Vincristine (1.5 mg/m² Dmax 2mg D1 i.v.) and temozolomide (100 mg/m² D1-5 p.o.) were given every 21 days. Primary objectives were safety and tolerability.

Results: 24 children and 24 adults were enrolled from 2024.04.15 to 2024.12.30. 16 children and 19 adults were enrolled in phase 1a part. 8 more children and 5 more adults were enrolled in phase 1b part. Finally, 11 children and 11 adults were treated at RP2D dose. No dose-limiting toxicity (DLT) was found at level 1 and 2 in both cohorts. 0/3 and 1F/6 DLT was found at level 3 in each cohort respectively, while 2/6 and 2/6 DLTs were found at level 4. RP2D established at level 3 of 35 mg/m² NALIRI. For patients at RP2D dose, confirmed objective response (ORR) was 54.5% in both cohorts, while clinical benefit rate (CBR) was 81.8% in cohort A and 63.6% in cohort B. The median PFS was 3.6 (95% CI, 2.7-NA) months in total and OS was not matured. Duration of response (DOR) was 4.3 months. Grade 3/4 toxicities were found in hematologic toxicity (most common), anorexia, fatigue, nausea or vomiting, pain and diarrhea.

Conclusion: NALIRI-VT demonstrates manageable toxicity and promising activity in advanced Ewing sarcoma, warranting further investigation in phase II trials.