Company: SHPH
Filing Date: 2025-03-05
Form Type: S-1/A
Source: 0001493152-25-009106
Chunk: 12

Company: Shuttle Pharmaceuticals Holdings, Inc.
Filing Date: 2025-03-05
Form: S-1/A
Chunk 12
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R, Grindrod S, Aghdam N, Li X, Gracia-Hernandez M, Zevallos-Delgado C,          
 Jung M, Villagra A, Dritschilo A. Radiotherapy-induced Immune Response Enhanced by Selective HDAC6 Inhibition. Mol Cancer Ther. 2023      
 Dec 1;22(12):1376-1389. doi: 10.1158/1535-7163.MCT-23-0215. PMID: 37586844; PMCID: PMC10878032) and additional preclinical studies        
 are in progress with our contractors. With the introduction of check-point inhibitors, CAR-T therapies and personalized medicine          
 in cancer, regulation of the immune response following RT is of significant clinical and commercial interest.                             |
| ● | SP-1-303                                                                                                                                  
 is Shuttle Pharma’s pre-clinical selective Class I HDAC inhibitor that preferentially affects histone deacetylases                        
 HDAC1 and HDAC3 members of the class I HDAC family of enzymes. SP-1-303 data show direct cellular toxicity in ER positive breast          
 cancer cells. Furthermore, SP-1-303 increases PD-L1 expression. Completed preclinical in vitro studies have been published (Jung          
 M, Nicholas N, Grindrod S, Dritschilo A. Dual-targeting class I HDAC inhibitor and ATM activator, SP-1-303, preferentially inhibits       
 estrogen receptor positive breast cancer cell growth. PLoS One. 2024 Jul 15;19(7):e0306168. doi: 10.1371/journal.pone.0306168. PMID:      
 39008483; PMCID: PMC11249239.). We plan to seek university collaborations to complete SP-1-303 pre-clinical development in 2024.          |

| 4 |

Our Approach

We believe that we have established a leadership position in radiation sensitizer and response modifier discovery and development. We have identified a clinical phase product candidate and discovered new pre-clinical phase molecules using our proprietary platform technologies to increase the therapeutic index for patients receiving radiation for treatment of solid tumors. Our development strategy has four key pillars: (1) to improve the efficacy of RT by demonstrating improved disease-free survival rates in patients who undergo radiation therapy, (2) reduce the amount of radiation needed for a favorable tumor response, thereby limiting the potential for radiation related toxicities to healthy cells,