SBIR-STTR Award

Hearing loss is a major health concern in our society, affecting over 360 million people worldwide (World Health Organization, 2017). Cisplatin chemotherapy causes permanent hearing loss in 40-60% of treated cancer patients. To date, no drugs have been approved by the Food and Drug Administration (FDA) for protection from cisplatin-, noise-, or age-related hearing loss. Most candidate compounds currently in pre-clinical trials are related to antioxidants, vitamins, and glutathione metabolism, and thus many of these compounds, such as sodium thiosulfate, can interfere with cisplatin’s ability to kill the tumor cells. We recently conducted unbiased high-throughput screens of bioactive compounds (total of 4,385 unique compounds) in a cochlear ear cell line and identified cyclin dependent kinase-2 (CDK2) as an important therapeutic target for cisplatin-induced cell death and hearing loss. In the following focused screen of an additional 187 CDK2 inhibitors that have desirable drug-like properties, we identified AZD5438 as the top hit, exhibiting an IC50 of 540 nM in the cochlear cell line and an excellent IC50 of 5 nM ex vivo in mouse P3 cochlear explants treated with cisplatin. AZD5438 was the most potent CDK2 inhibitor tested in our cochlear explant studies. Furthermore, by local delivery of AZD5438 to adult FVB mice, the compound showed full protection against cisplatin-induced ototoxicity as measured by Auditory Brainstem Response (ABR) thresholds and cochlear histology. AZD5438 also protected against cisplatin induced hair cell loss in vivo in zebrafish lateral line neuromasts at 100 nM. Here we will evaluate the potential to repurpose the anti-cancer small molecule AZD5438, an orally bioavailable CDK2 inhibitor that has already been found to be tolerated in healthy male volunteers and solid-tumor patients in phase I and phase II clinical trials, for protection against cisplatin-induced hearing loss. Our Specific Aim is to test whether AZD5438 protects from cisplatin-induced hearing loss by systemic delivery in a mouse model. Our approach is to administer AZD5438 by oral gavage to adult FVB mice treated with cisplatin, measure their ABR thresholds and analyze their cochlear histology. The maximum non-toxic dose of oral AZD5438 will be experimentally determined and tested for hearing-protective effects. This work will shed light on the possibility of using AZD5438 in an oral formulation to combat cisplatin-induced hearing loss. In comparison to local delivery, oral delivery of an effective pharmaceutical product has the advantage of patient convenience. In the future, we will also test the efficacy of oral AZD5438 to protect from noise- and age- related hearing loss. If oral delivery of AZD5438 proves protective in this study, we will apply for IND-enabling SBIR phase II studies for cisplatin- induced hearing loss in cancer patients. As the main inventors for CDK2 inhibitors for hearing loss, both founders of Ting Therapeutics LLC have already obtained the exclusive patent rights for AZD5438 and filed patent applications in Europe, China, Japan and Hong Kong, and are negotiating for licensing the US patent rights. Oral delivery of AZD5438, if successful, has the potential to be a significant step forward in treating cancer patients against cisplatin-induced hearing loss.

Public Health Relevance Statement:
PROJECT NARRATIVE The work in this proposal focuses on the development of an oral therapeutic small molecule AZD5438 against cisplatin-induced hearing loss. If successful, this project will be a significant step forward in the treatment of cisplatin-induced hearing loss in cancer patients.

Project Terms:
Adult; Affect; Animals; anti-cancer; Antioxidants; Auditory Brainstem Responses; Benchmarking; Bioavailable; Biological Assay; cancer clinical trial; Cancer Patient; cancer therapy; CDK2 gene; Cell Death; Cell Line; Cell Survival; chemotherapy; China; Cisplatin; cisplatin induced hearing loss; Cochlea; combat; Development; Dexamethasone; Dose; Drug Delivery Systems; Ear; ebselen; efficacy testing; Europe; Exhibits; follow-up; Formulation; Future; FVB Mouse; Glutathione Metabolism Pathway; Hair Cells; Health; Hearing; hearing impairment; Hearing Tests; high throughput screening; Histology; Hong Kong; in vivo; Industry; inhibitor/antagonist; Injury; inner ear diseases; Japan; kinase inhibitor; Labyrinth; lateral line; Legal patent; Libraries; Licensing; Light; local drug delivery; male; Measures; Mediation; Medical; Methionine; Mitochondria; mouse model; Mus; neoplastic cell; neuromast; Noise; Noise-Induced Hearing Loss; olomoucine; Oral; otoprotectant; ototoxicity; Patients; permanent hearing loss; Pharmaceutical Preparations; Pharmacologic Substance; phase 2 study; Phase I Clinical Trials; Phase II Clinical Trials; preclinical trial; Presbycusis; Production; Property; protective effect; Rattus; Reactive Oxygen Species; Resistance; Rights; Schedule; Small Business Innovation Research Grant; small molecule; small molecule therapeutics; Societies; sodium thiosulfate; Solid Neoplasm; systemic toxicity; Testing; Therapeutic; therapeutic target; Time; Toxic effect; United States Food and Drug Administration; vitamin metabolism; volunteer; Work; World Health Organization; Zebrafish

CDK2 inhibitors for protecting hearing lossTing Therapeutics LLC is a pharmaceutical company developing drugs to prevent and treat hearing loss.Cisplatin is one of the most widely used drugs to treat cancers. However cisplatin anticancer therapy causeshigh frequency hearing loss in 40-60% of the patients. To date, no drugs have been approved by the Food andDrug Administration for protection from cisplatin-induced hearing loss. Most candidate compounds currently inpre-clinical and clinical trials are related to antioxidants, vitamins, and glutathione metabolism, and thus many ofthese compounds, such as sodium thiosulfate, can interfere with cisplatin's ability to kill the tumor cells. Werecently conducted unbiased high-throughput screens of bioactive compounds in a cochlear ear cell line andidentified cyclin dependent kinase-2 (CDK2) inhibitors as important therapeutic compounds for cisplatin-inducedcell death and hearing loss. Among those compounds, TT001 was the most potent CDK2 inhibitor tested. Resultsfrom our SBIR Phase I, demonstrated that oral TT001 ameliorated cisplatin-induced hearing loss with no generaltoxicity. Moreover, TT001 did not interfere with cisplatin anti-cancer activity in vitro. In this SBIR Phase II, we willperform Investigational New Drug-enabling experiments to test TT001's effect on cisplatin's tumor killing efficacyin vivo and to conduct efficacy studies to define an optimal dosing regimen and therapeutic index. The long-termgoal is for TT001 to become a standard otoprotective drug of cisplatin-based therapies. For this purpose, we willdemonstrate TT001's efficacy in a mouse model of cisplatin ototoxicity that mimics the administration protocol incancer patients (Aim1). We will determine pharmacokinetics and pharmacodynamics profiles in blood andperilymph, as well as efficacy, in a guinea pig model for cisplatin-induced hearing loss (Aim 2). This Aim will beperformed under contract with and independent and reputable Contract Research Organization, Turner ScientificLLC. Finally, we will verify that TT001 does not interfere with cisplatin's anti-cancer activity in vivo in mousemodel xenografts (Aim 3). By successfully completing these studies, Ting Therapeutics will obtain critical datanecessary for the initiation of Investigational New Drug-enabling Good Laboratory Practice complaint studiesand clinical trials. Ting Therapeutics LLC has the exclusive international rights for the use of CDK2 inhibitors inthe treatment of hearing loss. The company has filed for international patents in Japan, Europe, China and HongKong. The patent in Europe and China has been awarded; similar patent applications are pending in US, Japan(No 2020-156803), and Hong Kong. Ting Therapeutics is negotiating with St. Jude Children's Research Hospitalfor the US Method of Use patent rights on CDK2 inhibitors for hearing loss (US Patent Application No.62/181,755; PCT/US16/38384; WO 2016/205806). The completion of this proposal will allow Ting Therapeuticsto initiate conversations with pharmaceutical companies for the manufacturing and licensing of TT001.

Public Health Relevance Statement:
PROJECT NARRATIVE The work in this proposal focuses on further development of TT001 to protect from cisplatin- induced hearing loss, an anticancer drug that leaves 40-60% of the treated cancer patients with high frequency hearing loss. If successful, this proposal will allow Ting Therapeutics to initiate conversations with pharmaceutical companies for the manufacturing and commercialization of TT001, for its use as a standard otoprotective component of cisplatin-based therapies.

Project Terms: