FDA staff that participated in the review of Ariad’s leukemia therapy ponatinib.

FDA rejected two of the sponsor’s labeling proposals because they failed to adequately address safety issues seen in the PACE trial. Ariad apparently preferred to quantify in labeling only treatment-emergent adverse events that investigators attributed to ponatinib – an approach FDA disdains for single-arm studies.

FDA reviewers and outside experts discussed at length concerns about cardiovascular and other adverse events in the single-arm PACE trial but believed ponatinib’s impressive efficacy in a difficult-to-treat leukemia population warranted bringing the drug to market. Sales of the tyrosine kinase inhibitor were halted less than 11 months later as safety and dosing concerns continued to pile up.