Evaluation of the safety of C-1311 administered in a phase I dose-escalation trial as a weekly infusion for 3 consecutive weeks in patients with advanced solid tumors
2069 Background: C-1311 is the most active member of a new series of anti-cancer agents, the imidazoacridinones, specially designed compounds developed from research on the structure-activity relationships of other cancer therapies such as the anthracenediones (e.g. mitoxantrone) and the anthracyclines (e.g. doxorubicin). This first-in-man clinical trial was designed to assess the safety profile of C-1311 and determine the recommended dose upon weekly administration for 3 consecutive weeks, within a 28-day cycle. Methods: Patients with advanced solid tumors refractory to conventional therapy were enrolled. The dose escalation scheme was divided into 2 phases: an initial accelerated phase of cohorts of 1 patient at doubling doses and a modified Fibonacci phase of cohorts of 3 pts at 25–33% dose increments. The maximum tolerated dose (MTD) was defined as the dose at which 2/3 or 2/6 pts experienced a dose-limiting toxicity (DLT). The recommended dose (RD) was defined as the dose level below the MTD, confirmed by expansion of the cohort to 9 pts. Results: 16 pts received doses of 15, 30, 60, 120, 240, 480 and 640 mg/m2/wk. The 2 pts treated at 640 mg/m2 experienced a DLT (grade 3 neutropenia preventing the administration of the 2nd and 3rd dose of the first cycle respectively). The RD was defined as 480 mg/m2/wk (cohort of 9 pts). Six additional pts were treated at the RD in an extension study in which one of the first 2 doses was given orally. Overall, 2 serious adverse events have been reported as possibly drug-related, both consisting of post-infusion fever without evidence of infection, resolving within 24 hours. Transient neutropenia was the only recurring grade 3 or 4 drug-related adverse event (AE). Grade 1 or 2 AEs most commonly reported as drug-related were nausea, asthenia, vomiting and diarrhea. Stable disease was observed in 3 patients with advanced malignancy. One pt had a stable course over > 8 cycles, and two had stable courses over 4 cycles. Plasma drug concentrations were linear and proportional to dose. Conclusions: The recommended phase 2 dose of 480 mg/m2, weekly × 3 q 28 days, offers a predictable safety profile and excellent tolerability. [Table: see text]