Background Although safety and prognostic factors for overall survival (OS) have been extensively studied in Phase I clinical trials on patients with solid tumours, data on lymphoma trials are scarce. Here, we investigated safety, outcomes and prognostic factors in relapsed or refractory lymphoma patients included in a series of Phase I trials. Method and patients All consecutive adult patients with recurrent/refractory lymphoma enrolled in 26 Phase I trials at a single cancer centre in France between January 2008 and June 2016 were retrospectively assessed. Results 133 patients (males: 65%) were included in the analysis. The median (range) age was 65 (23-86). Aggressive non-Hodgkin, indolent non-Hodgkin and Hodgkin types accounted for 64%, 25% and 11% of the patients, respectively. The patients had received a median (range) of 3 (1-13) lines of treatment prior to trial entry. The median [95% confidence interval] progression-free survival and OS times were 3.0 [1.8-3.6] and 17.8 [12.7-30.4] months, respectively. High-grade toxicity (grade 3 or higher, according to the National Cancer Institute's Common Terminology Criteria for Adverse Events classification) was experienced by 56 of the 133 patients (42%) and was related to the investigational drug in 44 of these cases (79%). No toxicity-related deaths occurred. Dose-limiting toxicity (DLT) was encountered in 11 (9%) of the 116 evaluable patients. High-grade toxicity occurred during the DLT period for 34 of the 56 patients (61%) and after the DLT period in the remaining 22 (39%). The main prognostic factors for poor OS were the histological type (i.e. tumour aggressiveness), an elevated serum LDH level, and a low serum albumin level. Early withdrawal from a trial was correlated with the performance status score, the histological type and the serum LDH level. The overall objective response and disease control rates were 24% and 57%, respectively. Conclusion Performance status, LDH, albumin and histological type (tumour aggressiveness) appear to be the most relevant prognostic factors for enrolling Phase I participants with relapsed or refractory lymphoma. 39% of the patients experienced a first high-grade toxic event after the dose-limiting toxicity period, suggesting that the conventional concept of dose-limiting toxicity (designed for chemotherapy) should be redefined in the era of modern cancer therapies.
Keywords: Dose-limiting toxicity; Phase I clinical trial; Recommended phase II dose; Relapsed and refractory lymphoma; Study design.