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Pacylex Pharmaceuticals’s Zelenirstat Shows Potent in vitro Radiosensitization in Human Glioblastoma Models

Zelenirstat, a myristoylation inhibitor, was more effective than standard of care radiosensitizers including temozolomide, cisplatin, and 5-fluorouracil, at enhancing radiation killing of cultured human brain cancer cells
Key Takeaways
  • Zelenirstat, a myristoylation inhibitor in clinical development, markedly improved the ability of radiation to kill cultured human brain cancer cells.
  • Zelenirstat was more effective than clinically used radiosensitizers, including temozolomide, cisplatin, and 5-fluorouracil.
  • Orally administered zelenirstat is predicted to cross the blood brain barrier more efficiently than temozolomide, the current standard of care radiosensitizer for aggressive brain cancers.

Edmonton, Alberta, Canada, October 3, 2023.-- Pacylex Pharmaceuticals, a clinical stage pharmaceutical company focused on the development of therapies for hematologic and solid cancers, announced recent results generated at NIH using its lead drug, zelenirstat, presented at the Canadian Association of Radiation Oncology Annual Meeting in Montreal, Canada, on September 23, 2023.

The presentation, titled “Radiosensitization with Glioblastoma using Targeted Inhibition of N-Myristoylation” highlighted that:

  • Zelenirstat was more effective than clinically used radiosensitizers, which generally augment the effects of radiation by 10% to 30%, increasing the effects of radiation by 40% - 140%;
  • Orally administered zelenirstat is also predicted to cross the blood brain barrier more efficiently than temozolomide, the current standard of care radiosensitizer for aggressive brain cancers.

Dr. Deepak Dinakaran, MD, PhD, a radiation oncologist and clinician scientist who conducted this research at the US National Institute of Health, said, "Our results show that zelenirstat is a potent radiosensitizer in preclinical models of glioblastoma, and that it works through pathways that differ from available radiosensitizers, including temozolomide.” 

“Dr. Dinakaran's exciting mechanistic work and the magnitude of the radiosensitization effect he identified suggests that zelenirstat, which has a broad spectrum of preclinical anticancer activity, might also be added to radiation for a variety of non-brain cancers, including cancers of the head and neck, lung, rectum, and uterine cervix.” said John Mackey, CMO of Pacylex. “This opens up many new opportunities to benefit patients with common solid cancers.”


About zelenirstat 
Zelenirstat (formerly identified as PCLX-001) is a first-in-class, oral, small molecule N-myristoyltransferase (NMT) inhibitor being developed to treat patients with leukemia, lymphoma, and solid tumors. Zelenirstat selectively kills cancer cells in vitro and has been shown to regress hematologic malignancies and inhibit the growth of lung and breast cancer tumors in animal models. Zelenirstat is particularly effective against Diffuse Large B Cell Lymphoma (DLBCL) and Acute Myeloid Leukemia (AML) in animal disease models. In AML, it also selectively kills leukemic stem cells in vivo while sparing normal bone marrow cells.
Zelenirstat is currently being evaluated in a Phase 1/2a open-label study (NCT04836195) designed to evaluate the safety, tolerability, pharmacokinetics, pharmacodynamics, and clinical activity of zelenirstat in patients with relapsed/refractory (R/R) Non Hodgkin Lymphoma (NHL) and advanced solid malignancies who have progressed on all available standard therapies. 

About Pacylex Pharmaceuticals
Pacylex is a clinical-stage pharmaceutical company headquartered in Edmonton, Alberta, Canada, targeting hematologic and solid cancers with orally bioavailable NMT inhibitors. Pacylex has a US Subsidiary in the San Francisco Bay area. Zelenirstat is the lead drug in a new class of NMT inhibitors, enabling Pacylex to exploit NMTs as new clinical targets for cancer treatment. Pacylex is conducting a multi-center Phase 1 multiple ascending dose study in Canada in patients with R/R NHL and advanced solid tumors, and a Phase 2a dose expansion in patients with R/R NHL. The IND for a Phase 1 multiple ascending dose study in AML has been cleared and the FDA has granted zelenirstat both Orphan Drug Designation and Fast Track Designation for AML. The US Department of Defense is supporting the initial clinical investigation of zelenirstat in patients with AML. The Cure Cancer Foundation supported initial clinical studies through its World’s Longest Games. 

For additional information, please visit www.pacylex.com.
Twitter @Pacylex (https://twitter.com/pacylex

Key Takeaways
  • Zelenirstat, a myristoylation inhibitor in clinical development, markedly improved the ability of radiation to kill cultured human brain cancer cells.
  • Zelenirstat was more effective than clinically used radiosensitizers, including temozolomide, cisplatin, and 5-fluorouracil.
  • Orally administered zelenirstat is predicted to cross the blood brain barrier more efficiently than temozolomide, the current standard of care radiosensitizer for aggressive brain cancers.
Media Gallery
Quotes
Our results show that zelenirstat is a potent radiosensitizer in preclinical models of glioblastoma, and that it works through pathways that differ...
Dr. Deepak Dinakaran, MD, PhDRadiation Oncologist and Clinician Scientist, US National Institute of Health
Dr. Dinakaran's exciting mechanistic work and the magnitude of the radiosensitization effect he identified suggests that zelenirstat, which has a b...
John Mackey, MDChief Medical Officer
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Contacts
Michael Weickert Ph.D
michael.weickert@pacylex.com
650-218-1840
Chief Executive Officer