Shuttle Pharmaceuticals Holdings, Inc. announced the expansion of its patent portfolio following the issuance of a Canadian patent for its Histone Deacetylase (HDAC) inhibitor platform technology titled "Dual Function Molecules for Histone Deacetylase Inhibition and Ataxia Telangiectasia Mutated (ATM) Activation and Methods of Use Thereof." The company's HDAC pre-clinical inhibitor platform includes: SP-2-225 is Shuttle Pharma's pre-clinical Class IIb selective HDAC inhibitor that affects histone deacetylase HDAC6. SP-2-225 has effects on the regulation of the immune system. The interactions of radiation therapy with the immune response to cancers are of great current interest, offering insight into potential mechanisms for primary site and metastatic cancer treatment.

For this reason, Shuttle Pharma selected SP-2-225 as the candidate lead HDAC inhibitor for preclinical development. Shuttle Pharma is advancing drug manufacture and IND-enabling studies with the goal of enabling a Phase I clinical trial in 2024. With the introduction of check-point inhibitors, CAR-T therapies and personalized medicine in cancer, regulation of the immune response following RT continues to be of significant clinical and commercial interest.

SP-1-161 is Shuttle Pharma's pre-clinical candidate lead HDAC inhibitor, radiation sensitizing candidate product. This pan HDAC inhibitor initiates the mutated ataxia-telangiectasia response pathway. Using rational drug design, Shuttle Pharma discovered HDAC inhibitors and ATM activators capable of radiation sensitizing cancer cells and protecting normal cells.

The candidate drug may serve as a direct chemotherapeutic agent or as a radiation sensitizer for treating cancers. In preclinical studies, SP-1-161 protected normal breast epithelial cells (184A1) following exposure to ionizing radiation while increasing sensitivity of breast cancer cells (MCF7). SP-1-161 provides this dual function in a single molecule and this molecule is differentiated from other HDAC inhibitors by treatment of cancers while protecting normal cells.

SP-1-303 is Shuttle Pharma's pre-clinical selective Class I HDAC inhibitor that preferentially affects histone deacetylases HDAC1 and HDAC3 and is a member of the Class I HDAC family. SP-1-303 data show direct cellular toxicity in estrogen receptor (ER) positive breast cancer cells.