Maximizing treatment opportunities: assessing protocol waivers' impact on safety and outcome in the Drug Rediscovery Protocol.

ABSTRACT

PURPOSE: Although eligibility criteria are essential in trial design, overly restrictive criteria contribute to low accrual and limited generalizability. To enhance trial inclusivity, there has been growing interest in broadening eligibility criteria, especially for patients with advanced or treatment-refractory disease. Yet, the impact on patient safety remains uncertain. In the Drug Rediscovery Protocol (DRUP), protocol exceptions are frequently requested and occasionally granted. Here we describe the impact of these waivers on treatment safety and efficacy. PATIENTS AND METHODS: DRUP is a multicenter, non-randomized clinical basket trial treating therapy-refractory cancer patients with molecularly targeted- and immunotherapies outside their registered indications (NCT02925234). Here, all granted waivers were revised, analyzed in terms of safety and efficacy outcome, and compared with outcomes of included patients that did not receive a waiver. RESULTS: Between September 1st 2016 and September 1st 2021, protocol waivers were granted for 82 patients (8%) out of 1019 included patients in DRUP. Most waivers (45%) were granted for general- or drug-related eligibility criteria, other categories were out-of-window testing, treatment and testing exceptions. Serious adverse event rate was similar between patients that received a waiver (pW) and patients that did not (pNW) 39% vs. 41%, respectively (P=0.81). The clinical benefit (either objective response or stable disease ≥ 16 weeks) rate of pW was 40% versus 33% in pNW (P=0.43). CONCLUSION: Safety and clinical benefit were preserved in patients for whom a waiver was granted. These data support a more personalized approach in assessing eligibility criteria, especially in trials with widely used and approved drugs accruing patients without other treatment options.