FDA Issues Complete Response Letter to Plinabulin Application for Prevention of Chemotherapy-Induced Neutropenia

A complete response letter has been issued to BeyondSpring Pharmaceuticals for plinabulin plus granulocyte colony-stimulating factor for the prevention of chemotherapy-induced neutropenia.

The FDA has issued a complete response letter to the makers of plinabulin regarding a new drug application for the agent in combination with granulocyte colony-stimulating factor (G-CSF) as a prophylactic treatment against chemotherapy-induced neutropenia (CIN), according to a press release from developer BeyondSpring.1

The letter indicates that after reviewing the application, the FDA has determined that the treatment cannot be approved in its current form. The FDA stated that the application, which included findings from a single registration phase 3 trial, did not demonstrate clear significant benefit that would have warranted an approval and that a second, well-controlled clinical trial will be necessary to produce the evidence needed to support the regimen in a CIN indication.

Notably, plinabulin is the first agent submitted to the FDA for approval that could potentially be used in the first week of treatment with chemotherapy prior to G-CSF in order to prevent the onset of CIN and improve patient outcomes.

“BeyondSpring strongly believes that plinabulin in combination with G-CSF has significant potential to raise the standard of care in CIN, a devastating [adverse] effect of chemotherapy,” said Lan Huang, PhD, co-founder, chief executive officer, and chairwoman at BeyondSpring, said in a press release. “The company plans to request a meeting with the FDA and remains committed to its goal of bringing plinabulin to cancer patients in need globally.”

Plinabulin and G-CSF received priority review from the FDA in June 2021 based on findings from the pivotal phase 3 PROTECTIVE-2 trial (NCT03294577), which compared plinabulin/pegfilgrastim versus pegfilgrastim alone.2 Data from the trial included 1200 patients. The primary end point of improved grade 4 neutropenia in cycle 1 was met, with a rate of 13.6% in the plinabulin arm and 31.5% in the control arm (P = .0015).


  1. BeyondSpring Pharmaceuticals receives complete response letter from the FDA for plinabulin new drug application for prevention of chemotherapy-induced neutropenia (CIN). News release. BeyondSpring Pharmaceuticals. December 1, 2021. Accessed December 1, 2021. https://bit.ly/3pflFWJ
  2. BeyondSpring announces U.S. FDA acceptance and priority review of new drug application for plinabulin and G-CSF combination for the prevention of chemotherapy-induced neutropenia (CIN). News release. BeyondSpring, Inc. June 1, 2021. Accessed December 1, 2021. https://bit.ly/3fCQuAQ