Humanigen Inc (OTCMKTS:HGEN) said Wednesday that two abstracts on its promising key drug candidate lenzilumab will be presented at the upcoming annual meeting of the American Society of Hematology, in Florida.
The Burlingame, California, company’s lenzilumab, is a recombinant monoclonal antibody that neutralizes a substance that promotes growth of white blood cells, but is also tied to inflammations that can occur during CAR-T therapies and lead to side effects.
Pre-clinical work shows lenzilumab is effective in preventing the side effects and may make the CAR-T therapies more effective, according to Humanigen.
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In a statement, the clinical-stage biopharmaceutical company said the two abstracts are focused on granulocyte-macrophage colony-stimulating factor (GM-CSF) gene knockout and GM-CSF neutralization with lenzilumab, the company's proprietary Humaneered anti-human-GM-CSF immunotherapy.
Both abstracts have been accepted for presentation at the American Society of Hematology on December 9, at the Orange County Convention Center, in Orlando, Florida.
Improved overall survival
Humanigen said that using a xenograft model for relapsed acute lymphoblastic leukemia (ALL), which is a type of cancer of the blood and bone marrow that affects white blood cells, treatment with GM-CSF k/o CART19 resulted in “improved overall survival” compared to wildtype CART19.
The lack of myeloid cells in this model pointed to an “intrinsic effect” of GM-CSF on CAR-T cells, said the company.
"These results strongly indicate that CAR-T cells increase expression of GM-CSF receptor subunits when activated, resulting in modulation of CAR-T function,” said Humanigen CEO Cameron Durrant.
“Collectively, these results illuminate a novel mechanism for a direct modulatory effect of GM-CSF on activated CAR-T cells that helps to explain the improved survival with GM-CSF neutralization or knockout," he added.
Durrant, a medical doctor and MBA who assumed the role of CEO in March 2016, said the results of the company sponsored phase I study reinforce the favorable safety profile of lenzilumab even in patients with chronic myelomonocytic leukemia (CMML), a rare type of blood cancer, who have undergone several cycles of immunosuppressive therapy.
"As with all prior lenzilumab clinical trials, no serious treatment related adverse events were observed," said Durrant.
“Throughout the study there were no reported instances of dose limiting toxicities or adverse events grade 3 or higher related to the study drug. Additionally, of four subjects with NRAS mutations at screening, three either achieved clinical benefit or had clinical meaningful bone marrow myeloblast reductions,” he added.
Humanigen is developing a portfolio of next-generation cell and gene therapies for the treatment of cancers through its novel GM-CSF neutralization and gene-knockout platforms.
The company’s immediate focus is combining FDA-approved and development stage CAR-T therapies with lenzilumab, the company’s proprietary anti-human-GM-CSF immunotherapy, which is its lead product candidate.
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