A retrospective analysis of phase I and phase I/II investigator-initiated clinical trials conducted by the Swiss Group for Clinical Cancer Research (SAKK).

Background Phase I trials represent the initial step in the clinical evaluation of a new drug or new drug combination. The main characteristics and designs of phase I trials have changed throughout the years to better support the development of drugs with different specificities compared with traditional chemotherapy.Patients And Methods We reviewed early-stage investigator-initiated clinical trials conducted by the Swiss Group for Clinical Cancer Research (SAKK) within the last 20 years at a patient and clinical trial level. For efficacy analysis, patients were grouped into advanced/metastatic solid tumors, nonadvanced solid tumors, and lymphoma.Results The study included 295 patients from 20 clinical trials. Systemic drug combinations were the most common treatment modality (39.3%), followed by multimodal treatments (29.8%) and monotherapy (24.7%). Dose-limiting toxicities were observed in 8.8% of patients [95% confidence interval (CI) 5.8% to 12.6%]. Grade ≥3 adverse events occurred in 60.3% of patients (95% CI 54.5% to 66.0%), most frequently in those receiving combinations (74.1%). No treatment-related deaths were observed. In advanced solid tumors, the overall response rate was 25.8% (95% CI 18.4% to 34.4%), with a median progression-free survival of 5.8 months (95% CI 4.8-8.0 months) and an overall survival of 1.5 years (95% CI 1.2-2.2 years). Nonadvanced solid tumors demonstrated a median progression-free survival of 78.8 months, while overall survival was not reached (NR) (95% CI 62.3-NR months). The overall response rate in lymphoma patients was 81.3% (95% CI 67.4% to 91.1%), with a median progression-free survival of 30.8 months and an overall survival was NR (95% CI 10.8-NR months).Conclusion These findings highlight the safety profile, efficacy outcomes, and diversity of treatments in SAKK-conducted phase I trials, providing valuable insights into the investigator-initiated early clinical trials landscape in Switzerland.