High-dose continuous-infusion ifosfamide in advanced thymic epithelial Tumors: A TYME network study

Background: We reported the efficacy and safety results of high-dose, continuous-infusion Ifosfamide, in patients with advanced thymoma (TM) and thymic carcinoma (TC).Methods: This was a multicentric, prospective study in patients with advanced TM or TC, who had progressed after at least one line of platinum-based chemotherapy. Previous treatment with an anti-angiogenesis or anti-PD(L)1 was allowed. Patients received Ifosfamide (1 g/m2/day) and sodium-2-mercaptoethanesulfonate (1 g/m2/day), as continuous infusion, via a portable pumps for 14 consecutive days.Treatment was administered every 4 weeks until progression or unacceptable toxicity, up to a maximum of 6 cycles. The primary endpoint was the overall response rate (ORR) assessed by RECIST1.1. Secondary endpoints included disease control rate (DCR), Progression-free survival (PFS), overall survival (OS), and safety. Results: Eighteen patients were enrolled from October 2020 to January 2022. Twelve patients had a TC, 5 a TM and 1 a mixed TM/TC. Sixty-one percent of patients (11/18) had stage IVB disease according to Masaoka-Koga, and 39% (7/18) had an ECOG-PS 2. The median number of previous lines of therapy was 2 (range:1-5), and 72% (13/18) and 61% (11/18) of patients were pretreated with an anti-angiogenesis drug and an anti-PD(L)1 drug respectively. The ORR and the disease control rate (DCR) were 28 % (95 %CI: 10 %-53 %) and 67 % (95 %CI: 41 %-86 %), respectively. The median follow-up for PFS was 17.3 months (95 %CI: 4.3-NA), and median PFS was 5.4 months (95 %CI: 2.9-6.4). The median duration of response and SD was respectively 19.6 months (95 %CI: 3.5-NA) and 6.0 months (95 % CI: 3.8-6.4). In patients with TC, the ORR and DCR were 15 % (95 % CI: 2 %-45 %) and 54 % (95 % CI: 25 %-81 %), respectively. In the subgroup of 5 patients with TM, 2 PR and 3 SD were observed.Most patients had only mild (grade 1-2) AEs, the most common being nausea and vomiting (39%; 7/18) and transaminases elevation (33%; 6/18). Twenty-two percent of patients (4/18) experienced an AEs of grade 3 and required ifosfamide dose reduction. No patients had severe AEs.Conclusion: High-dose continuous-infusion Ifosfamide can be considered as a valuable treatment option in patients with advanced thymic epithelial tumors.