Optimizing early phase clinical trial washout periods: a report from the Therapeutic Advances in Childhood Leukemia and Lymphoma consortium.

Background: The National Cancer Institute (NCI) issued a 2021 memorandum adopting the American Society of Clinical Oncology (ASCO) and Friends of Cancer Research (Friends) task force recommendations to broaden clinical study eligibility criteria. They recommended that washout periods be eliminated for most prior cancer therapy and when required to utilize evidence- and/or rationale-based criteria. The Therapeutic Advances in Childhood Leukemia and Lymphoma (TACL) consortium responded to this guidance.

Methods: A TACL task force reviewed the consortium's research portfolio, the relevant literature and guidance documents from ASCO-Friends, NCI, and US Food and Drug Administration to make expert consensus and evidence-based recommendations for modernizing, broadening, and codifying TACL-study washout periods while ensuring consistency with pediatric ethics, and federal regulations. TACL's screening log was reviewed to estimate the impact that updated washout periods would have on patient inclusivity and recruitment.

Results: Over a 19-year period, 42 (14.6% of all screened ineligible patients [n = 287]) patients were identified as excluded from TACL early phase studies exclusively because of not meeting washout criteria. An additional 6 (2.1%) did not meet washout and at least 1 other exclusion criterion. A new TACL washout guidance document was developed and then adopted for use. Where washout criteria were not eliminated, rationale- and/or evidenced-based criteria were established with citation.

Conclusion: In an effort to reduce unnecessary exclusion from clinical trials, TACL created rationale- and/or evidenced-based washout period standards largely following guidance from the NCI and ASCO-Friends recommendations. These new, expanded eligibility criteria are expected to increase access to TACL clinical trials while maintaining safety and scientific excellence.