Edmonton, Alberta, Canada June 10, 2025. Pacylex Pharmaceuticals Inc. (Pacylex) is a clinical-stage pharmaceutical company and world leader in N-myristoyltransferase inhibitors (NMTis) for cancer. Oral zelenirstat is a proprietary, potent, NMTi in clinical trials as a first-in-class treatment for hematologic cancers. Pacylex has many potent NMTis as potential payloads for antibody drug conjugates (ADCs) for the treatment of solid tumor cancers. Today Pacylex announced that it is meeting with potential partners and investors at the Biotechnology Innovation Organization (BIO) International Convention on June 16-19, 2025, at the Boston Convention and Exhibition Center, in Boston, Massachusetts, USA. The BIO Convention is the premier life sciences networking conference in the world, bringing together leaders, innovators and investors from the pharmaceutical, biotech and medical device industries.
Myristoylation is a protein modification essential to multiple cancer processes including assembly, translocation, and/or function of validated targets such as B-cell receptor, Flt3-cKit complex, EGFR, and VEGFR. Myristoylation is also essential for Complex I formation in the newly formed mitochondria of cancer cells, and its inhibition shuts down oxidative phosphorylation, which is critical for metastasis and cancer stem cell survival.
Pacylex is the only company developing an oral inhibitor, zelenirstat, of the enzymes essential for myristoylation, N-myristoyltransferases (NMTs). Zelenirstat was well tolerated in Phase 1 patients with 14 different types of cancer including refractory/relapsed lymphoma and refractory solid tumors with an average of 4 prior lines of treatment. Oral zelenirstat showed a better safety profile than many cancer drugs, and patients receiving the recommended Phase 2 dose (RP2D) had significantly better progression-free and overall survival than those treated at lower doses; 57% had stable disease or better for 6-16 months. A Phase 2a patient with DLBCL achieved both an anatomic and metabolic partial response. Acute myeloid leukemia patients are now being dosed with oral zelenirstat in another study. Clinical combinations with other oral therapies are planned based on synergy observed in vitro. Zelenirstat is also a potent radiosensitizer in prostate cancer and glioblastoma models.
Antibody drug conjugates (ADCs) are a powerful tool in cancer therapy but suffer from a limited number of ADC payloads. NMT inhibitors regress solid tumor cancers in animal models when used as ADC payloads. Pacylex has exclusive license to 503 NMTis, 28 of which have single-digit nM IC50s against human NMT1. Pacylex is working with partners to develop several of its most potent molecules as payloads for ADCs.
“Encouraging clinical and ADC results reinforce our commitment to develop both oral zelenirstat and NMTis as ADC payloads”, said Dr. Michael Weickert, CEO of Pacylex. “BIO is a key opportunity to expose potential partners and investors to our first-in-class oral zelenirstat to treat blood cancers, and NMTis as novel and effective payloads for partners’ ADC programs for solid tumors.”
For more information:
Pacylex Pharmaceuticals Contact: Michael J. Weickert
CEO, Pacylex Pharmaceuticals, Inc.
P: 650-218-1840
About zelenirstat (aka PCLX-001 or DDD86481)
Zelenirstat (formerly identified as PCLX-001 or DDD86481) is a first-in-class, oral, small-molecule NMTi being developed to treat patients with leukemia, lymphoma, and for the treatment of solid tumors when used as a payload for ADCs. 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.
Pacylex completed and published a
Phase 1 multiple ascending dose safety, tolerability, and pharmacokinetics study on zelenirstat in patients with relapsed/refractory lymphoma and refractory solid tumors (
NCT04836195). Zelenirstat demonstrated an acceptable safety and tolerability profile, pharmacokinetics consistent with once-daily oral dosing, and early signs of efficacy. A clinical study in relapsed/refractory AML patients is now underway (ClinicalTrials.gov ID
NCT06613217).
About Pacylex Pharmaceuticals
Pacylex is the world leader in developing N-myristoyltransferase inhibitors (NMTis) as targeted therapies for the treatment of hematologic cancers and as payloads for antibody drug conjugates (ADCs) for solid tumors. Pacylex is conducting clinical studies of its lead drug, oral Zelenirstat, the first and only clinically validated NMTi. 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 AML patients. Pacylex is headquartered in Edmonton, Alberta, Canada, but also has an office in the San Francisco Bay area. The Cure Cancer Foundation, Alberta Cancer Foundation, and Alberta Innovates supported the initial clinical studies. For additional information, please visit
www.pacylex.com.
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