The Food and Drug Administration (FDA)‘s draft guidance on clinical outcome assessments (COA) gave CLL Society an opportunity to share with the Agency why CLL can be a difficult area for research & development (R&D), and that, as a chronic blood cancer, treatment value from a patient’s perspective might turn more towards durability of response.
We agreed with FDA that COA should reflect a meaningful aspect of patient health, support an inference of treatment effect, and sample sizes be calculated based on the primary endpoint. However, we also shared our concern that the Agency does not discourage use of COA by requiring a sample size so large as to make them infeasible, and that FDA acknowledge that use of historical controls or other comparators are appropriate for patient populations in which randomized trials are not feasible.
Our comments also included recommendations for the FDA to (i) reconsider that COA scores obtained at screening cannot be used as a patient baseline value, and (ii) clarify that in obtaining COA scores periodically sometimes circumstances may make repeat assessments unnecessary or even inappropriate. In the first recommendation, COA’s like MRD or organ function lab studies are not likely to be concerning. In the latter, repeated imaging with CT scans, for example, should be avoided for those living with CLL or SLL.