On December 15, 2021 BeyondSpring Pharmaceuticals (the "Company" or "BeyondSpring") (NASDAQ: BYSI), a global pharmaceutical company focused on the development of cancer therapeutics, reported new data highlighting the mechanism of action of plinabulin in the prevention of chemotherapy-induced neutropenia (CIN) at the 63rd American Society of Hematology (ASH) (Free ASH Whitepaper) Annual Meeting and Exposition, held virtually and in person in Atlanta, Georgia from December 11-14, 2021 (Press release, BeyondSpring Pharmaceuticals, DEC 15, 2021, View Source;utm_medium=rss&utm_campaign=beyondspring-pharmaceuticals-announces-new-clinical-data-confirming-plinabulins-fast-onset-mechanism-of-action-in-the-prevention-of-chemotherapy-induced-neutropenia-at-the-63rd-ash-annual-mee [SID1234597188]). The data demonstrate that adding plinabulin to a myelosuppressive regimen rapidly reversed (within 24 hours) neutropenia and leukopenia in the PROTECTIVE-1 and -2 clinical studies by protecting progenitor stem cells in the bone marrow.

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"This clinical data provides evidence confirming the hypothesized progenitor stem cell protective mechanism of action for plinabulin, which further validates the positive Phase 3 data from the PROTECTIVE-2 clinical program. These data also build upon the rapid effect seen in clinical trials to date and support the opportunity for enhanced CIN prevention care with plinabulin," said Dr. Douglas Blayney, professor of medicine at Stanford University Medical School and global principal investigator for the CIN studies. "These data provide a strong rationale for combining plinabulin with pegfilgrastim, since the latter has a mechanism of action exerting CIN prevention in week 2 of the chemotherapy cycle while plinabulin shows a week 1 benefit. This early CIN benefit is critically important because these white blood cells are the body’s main source of defense against infection. If a cancer patient gets an infection due to CIN, it may affect their ability to finish chemotherapy for cancer treatment."

Dr. Ramon Mohanlal, executive vice president of research and development and chief medical officer at BeyondSpring Pharmaceuticals, added, "This presentation at ASH (Free ASH Whitepaper) provides mechanistic support for the observed benefit of plinabulin in the prevention of CIN, a condition that still has unmet medical need, despite the availability of the standard of care CIN prevention drug, G-CSF. In addition, the rapid onset of action is critical since week 1 of each chemotherapy cycle is when more than 75% of CIN cases occur, even with G-CSF. Investigating the nuances of how and when plinabulin works is a continuous part of our work in understanding this multifaceted therapy. We look forward to sharing more of these insights with the oncology community in future studies."

This poster was presented on Sunday, December 12, 2021 and is available on the ASH (Free ASH Whitepaper) website.

Poster Title: Plinabulin Rapidly (within 24 Hours) Reverses Myelosuppression Induced by Chemotherapy
Abstract Number: 2056
Key Findings:

This new data analysis from the PROTECTIVE-1 and 2 studies aimed to further evaluate plinabulin’s fast onset mechanism of action (MoA) and potential progenitor stem cell involvement in plinabulin’s fast onset MoA.
The comparison was made between cancer patients receiving plinabulin 40 mg (n=228) or not receiving plinabulin (n=172), and with all patients receiving myelosuppressive chemotherapy (docetaxel with or without doxorubicin and cyclophosphamide). Plinabulin 40 mg was given 30 minutes after chemotherapy.
Plinabulin rapidly (within 24 hours) reversed chemo-induced myelosuppression in both the PROTECTIVE-1 and 2 human studies. Plinabulin-mediated increases in cell numbers are dose-dependent and correlated among cells of the myeloid, lymphoid and erythroid lineages.
Neutrophils (p<0.0001; increase by >3x10E9/L with plinabulin and decrease by >0.5x10E9/L without plinabulin)
Monocytes (p=0.0023)
Eosinophils (p=0.0775)
Basophils (p<0.0001)
The data suggest that plinabulin targets granulocyte-monocyte-progenitor (GMP) stem cells (N, M, B and E progenitor) as well as progenitor cells further upstream in the hematopoietic lineage.
About Plinabulin
Plinabulin, BeyondSpring’s lead asset, is a selective immunomodulating microtubule-binding agent (SIMBA), which is a potent antigen presenting cell (APC) inducer. It is a novel, intravenous infused, patent-protected asset for CIN prevention and a Phase 3 anti-cancer candidate for non-small cell lung cancer (NSCLC) with recently released positive topline data. Plinabulin triggers the release of the immune defense protein, GEF-H1, which leads to two distinct effects: first is a durable anticancer benefit due to the maturation of dendritic cells resulting in the activation of tumor antigen-specific T-cells to target cancer cells, and the second is early-onset of action in CIN prevention after chemotherapy by boosting the number of hematopoietic stem/progenitor cells (HSPCs). Plinabulin received Breakthrough Therapy designation from both U.S. and China FDA for the CIN prevention indication. As a "pipeline in a drug," plinabulin is being broadly studied in combination with various immuno-oncology agents that could boost the effects of the PD-1/PD-L1 antibodies and re-sensitize PD-1/PD-L1 antibody-resistant patients.