Lurtotecan Liposomal(Gilead)

The purpose of this study was to evaluate the activity and safety of OSI-211, the liposomal form of lurtotecan, in patients ineligible for curative surgery or radiotherapy and with metastatic/locoregional recurrent squamous cell carcinoma of the head and neck (SCCHN) and target lesions either within a previously irradiated field ("within") or outside a previously irradiated field ("outside"). OSI-211 was given intravenously over 30 min on days 1 and 8 at 2.4 mg/m2/day, repeated every 21 days (1 cycle). From July 2001 to March 2002, 32 patients from 14 institutions were enrolled in the "within" arm and 18 in the "outside" arm. In the "within" arm, two patients were ineligible because their tumour site was not allowed in the protocol (nasopharynx, skin) and two other patients never started treatment. Of the 46 eligible patients who started treatment, there was one objective response (response rate: 2.2% (95% Confidence Interval (CI): [0-11.5%]). Twelve patients in the "within" arm and 6 in the "outside" arm had stable disease, with a median duration of 18 weeks, 95% CI (12.7-25.7). The median time to progression was 6 weeks (95%CI: [5.9-12.7] weeks). Haematological toxicity was moderate in both arms. The most common haematological toxicity was grade 1-2 anaemia in 79% of patients. Non-haematological toxicity was mild in both arms. The most common grade 3-4 non-haematological toxicity was infection in 8.5% of patients. OSI-211 administered on d1 and d8, every 3 weeks, is well tolerated, but shows only minimal activity in locally advanced/metastatic SCCHN.

To define the maximum tolerated dose (MTD), recommended phase II dose (RD) and dose limiting toxicity (DLT) of liposomal lurtotecan, OSI-211 (formerly known as NX211), given as a short intravenous infusion on days 1, 2, and 3 every three weeks.

Thirty-seven patients were enrolled and treated in a dose escalation study from a starting dose of 0.15 mg/m(2) daily x 3 to 2.1 mg/m(2) daily x 3. Detailed pharmacokinetic analyses of blood were done on both days 1 and 3 of the first cycle and toxicity was monitored.

Two MTDs were defined; one for patients defined as minimally pretreated and one for those heavily pretreated. Dose limiting toxicity was myelosuppression: primarily thrombocytopenia although neutropenia was also noted. The MTD was 2.1 mg/m(2)/d (total dose of 6.3 mg/m(2)) in minimally pretreated patients and 1.8 mg/m(2)/d (5.4 mg/m(2) total dose) in heavily pretreated patients. Pharmacokinetics revealed that AUC and C (max) increased with dose and were significantly higher than that of free lurtotecan (AUC approx. 100 fold higher). The half life and duration of the active lactone form were also significantly longer than historical data on free drug. Two partial responses were seen, one each in a patient with breast and ovarian cancer.

Two Phase II recommended doses were established for OSI-211 given as a daily x 3 schedule every three weeks. The recommended phase II dose is 1.8 mg/m(2) daily x 3 for minimally pretreated patients and 1.5 mg/m(2) for those heavily pretreated. Phase II studies should be initiated in sensitive tumours.