Objectives
Stringent eligibility criteria (EC) in trials are a barrier especially for Phase I (P1) trial participation. Patients with cancer often seek P1 trials as access to investigational products (IP) with potential benefit. Due to organ toxicities, cytotoxic drug trials have high lab thresholds for participant eligibility. It is unclear how the rise of non-cytotoxic drugs is affecting EC in P1 trials. This study reviews variability in laboratory parameters within EC across P1 trial protocols and its impact on recruitment and outcomes.
Sample
Sixty-six P1 trial protocols at Southern Oncology Clinical Research Unit, Adelaide between 2020 and 2025 were included.
Procedures
Data extracted included IP type, sponsor location, and common EC laboratory parameters. A descriptive summary of the data is being presented.
Results
Most protocols evaluated immunotherapy (n=33) or targeted therapies (n=27); the rest were antibody drug conjugates or other novel IPs (n=6). 63% of trials were sponsored by US organisations. Laboratory parameters were dominantly placed within inclusion criteria (93%). A haemoglobin cut-off of 90 g/L was in 90% of trials, while four did not specify a threshold. Platelet count requirements were set at 100 ×10⁹/L in 72% of trials, while others allowed a lower threshold (≥75 ×10⁹/L). 53% of trials had a creatinine clearance cut-off of ≥ 45 ml/min. Serum albumin criterion demonstrated a wide variation (range 20-30 g/L), and 72% without specific requirement. IP type or sponsor location did not significantly affect these lab parameter thresholds.
Conclusion
Most P1 oncology trial protocols apply similar laboratory EC regardless of the IP type. Some possible reasons include EC not based on the IP under evaluation, persistent use of a standard protocol template across P1 trials, regulatory requirements and limiting inclusion to only fit participants. Further analysis will investigate the effect of these criteria on trial access, enrolment and participant outcomes.