Phase I dose escalation and pharmacokinetics clinical trial of mitoxantrone hydrochloride liposome in children with relapsed and refractory solid tumors.

Abstract

10047 Background: Compared with solvent-based mitoxantrone, mitoxantrone hydrochloride liposome has been found to reduce bone marrow toxicity. This open-label, muti-center, single-arm phase I clinical trial aims to evaluate the safety and efficacy of mitoxantrone hydrochloride liposome in pediatric with solid tumors. Methods: The study was divided into Phase Ia and Ib. Phase Ia was the dose escalation study, with a "3+3" design. Patients received mitoxantrone hydrochloride liposome at three dose levels (16 mg/m2, 20mg/m2, 24mg/m2, d1) in combination with irinotecan (50mg/m2, d1-5) and vincristine (1.5mg/m2, d1) every 3 weeks. Pharmacokinetic studies were conducted simultaneously. The primary endpoint of Phase Ia was the maximum tolerated dose (MTD). In phase Ib, patients received the combination therapy of mitoxantrone hydrochloride liposome at the MTD dose. The primary endpoint of Phase Ib was the incidence and severity of hematological adverse events. Secondary endpoints in both phases included objective response rate (ORR), pharmacokinetic (PK) parameters, and others. Results: From October 2022 to January 2024, a total of 51 pediatric patients with relapsed and refractory solid tumors were enrolled, 28 patients in Phase Ia and 23 patients in Phase Ib. The median age was 10.0 years (range: 3, 21). All Patients could be evaluated for toxicity and 40 for efficacy. The MTD of mitoxantrone hydrochloride liposome was determined to be 24mg/m2. The results of pharmacokinetic analysis were not returned. Highest incidence of hematological and non-hematological adverse events (AEs) were anaemia (88.2%), diarrhea (84.3%). The newly found or aggravated TnIUtra, BNP value abnormality and lower LV function after medication were 4 (11.8%), 5 (14.3%) and 0 (0.0%), respectively. The overall ORR and DCR were 50.0% (95% CI: 33.8% - 66.2%) and 90.0% (95% CI: 76.3% -97.2%). 13 patients (25.0%) treated with mitoxantrone hydrochloride liposome combination regimen received the opportunity of surgery. Conclusions: The mitoxantrone hydrochloride liposome combination regimen has demonstrated an acceptable toxicity profile and promising clinical efficacy in pediatric patients with solid tumors, especially in sarcomas. Clinical trial information: NCT05620862 .