IMPACT Therapeutics announced that its ATR inhibitor IMP9064 has received the IND clearance from the U.S. Food and Drug Administration (FDA) for the Phase I/II clinical study, which will begin soon in the U.S. This will be the first in human study for the ATR inhibitor of IMPACT Therapeutics, representing a major leap of the company's global development strategy for its synthetic lethality pipelines.

This study is designed as a Phase I/II, dose escalation and expansion study, including individual arms to evaluate the safety, pharmacokinetics, and anti-tumor activities of IMP9064 as monotherapy and in combination with PARP inhibitor Senaparib in patients with advanced solid tumors.

IMP9064 is an ATR inhibitor discovered and developed by IMPACT Therapeutics, with worldwide intellectual property rights. In preclinical studies, IMP9064 was found to be a highly potent ATR inhibitor and is selective against other kinases. Additionally, IMP9064 has demonstrated high activities in several ATM-deficient cell lines and more active than reference compound in xenograft in vivo models, which could potentially lead to a wider therapeutic window, better tolerability in long-term administration as a single agent, and providing more flexibility in combination therapy. Senaparib, a PARP inhibitor developed by IMPACT Therapeutics, has been explored in several clinical studies worldwide. IMP9064 in combination with Senaparib will be evaluated in this clinical study to explore the combination therapy of an ATR inhibitor and a PARP inhibitor, which is highly anticipated in the DNA Damage Response (DDR) research field.

ATR is a synthetic lethality target of ATM mutations, which are commonly found in hematologic malignancies as well as a variety of solid tumors. ATR inhibitors have demonstrated proof-of-concept (POC) efficacy data in tumors harbored ATM mutations in previous clinical studies, and ATR is considered as one of the most promising synthetic lethality targets after PARP. Data from an ongoing ATR inhibitor clinical study presented at TRIPLE Conference 2021 showed that ATR inhibitor exhibits good efficacy as a monotherapy, but there is still significant room for improvement. This raised stronger interest to investigate combination of ATR inhibitor with other drugs. Among them, the combination of ATR inhibitor with PARP inhibitor is especially promising. In addition, the combination of ATR inhibitor with PARP inhibitor might overcome PARP inhibitor monotherapy resistance. As a company with both ATR inhibitor and PARP inhibitor in development, IMPACT Therapeutics is better positioned to study the combination therapy of ATR inhibitor with PARP inhibitor.

Combination therapy approach has been widely recognized as a major trend in the development of synthetic lethality-based therapeutics and targeted anticancer therapeutics to expand indications as well as to enhance anti-tumor activity. As a biopharmaceutical company dedicated to the discovery and development of novel therapeutics based on synthetic lethality, IMPACT Therapeutics has built extensive DNA Damage Response (DDR) pipelines including PARP, Wee1, ATR, and ATM inhibitors. IMPACT's compounds were uniquely designed to have high activity and selectivity, which enables the company to target broader cancer indications and provide more opportunities for its in-house combination therapies.

Dr. Chih-Yi Hsieh, Senior Vice President and Chief Medical Officer said, "The pre-clinical data of IMP9064 has demonstrated its superiority among the same-class compounds. The clearance of this clinical program in the U.S. will enable us to validate the high potency, high selectivity, and robust anti-tumor activity of IMP9064 in the clinical study. IMPACT has formulated a differentiated clinical strategy for our ATR inhibitor which could advance the clinical development as efficient as possible, expand our synthetic lethality pipelines, and benefit more patients worldwide."

About IMPACT Therapeutics

IMPACT Therapeutics is a biopharmaceutical company dedicated to the discovery and development of targeted anti-cancer therapeutics based on synthetic lethality. IMPACT Therapeutics has assembled one of the most comprehensive DNA damage response (DDR) global pipeline of novel drug candidates generated by in-house discovery efforts and is expanding to other novel synthetic lethality targets to broaden its pipeline. IMPACT pipeline products include PARP inhibitor (Senaparib/ IMP4297), Wee1 inhibitor (IMP7068), and other novel DDR pathway inhibitors. The lead clinical program, PARP inhibitor (Senaparib/ IMP4297), is in Phase II/III studies for ovarian cancer, prostate cancer, small cell lung cancer and other indications worldwide, including China. Senaparib's preliminary clinical data demonstrated superior tolerability and wider therapeutic window compared with other PARPi. Phase I study of Wee1 inhibitor (IMP7068) is conducted globally. ATR Inhibitor IMP9064 has received IND Clearance by FDA to start clinical studies in the U.S. and Hedgehog pathway inhibitor (IMP5471) has received IND approval from NMPA to initiate clinical studies in China.

Source: IMPACT Therapeutics