Discussant Heather L. McArthur, MD, MPH, Medical Director of Breast Oncology at Cedars-Sinai Medical Center, Los Angeles, called the plinabulin findings “provocative,” especially considering the substantial impact on durability of response. Specifically with the addition of plinabulin to docetaxel, the median duration of response improved from 1.5 months to more than 1 year. She labeled this result “dramatic,” given that this shift in median responses means that more than “half the patients in the experimental arm are responding for more than 1 year vs 1.5 months on average in the control arm.”
Despite these dramatic responses, several questions were raised. It is difficult, Dr. McArthur conceded, “to wrap my mind around why [patients with] measurable lesions and thus, larger tumor burdens, would derive a survival benefit from the intervention when compared with patients with lower risk disease.” She questioned why the dramatic improvement in duration of response did not translate into a survival benefit and whether the use of single-agent docetaxel represented a modern control arm given that targeted therapies and more recently immune-modulating agents have been U.S. Food and Drug Administration–approved for the palliative treatment of many non–small cell lung cancers.
“I do think we still have a lot to learn about plinabulin,” Dr. McArthur said. It will be important, for example, to decipher the direct antitumor effects of the agent from its immune-related effects. ■
Disclosure: Dr. McArthur is on the advisory boards of Celgene, Merck, OBI Pharma, Roche, Spectrum Pharmaceuticals, Syndax Pharmaceuticals, Roche, Peregrine, and Calithera; and her current reseach is supported by Bristol-Myers Squibb, Eli Lilly, MedImmunne, LLC/AstraZeneca and Merck.