Abstract 4307
Background
Oncogenic activation of the receptor tyrosine kinase (RTK) RET via point mutation or genomic rearrangement has been identified in multiple cancers, including medullary and papillary thyroid cancers, and non-small cell lung cancer (NSCLC). Two multi-kinase RET inhibitors vandetanib and cabozantinib have been approved for thyroid cancer. Current investigational RET inhibitors BLU-667 and LOXO-292 have demonstrated efficacy in RET aberrant NSCLC and thyroid cancers. Multiple resistance mutations have been reported from preclinical studies, including the gatekeeper mutation V804L to cabozantinib and solvent front mutations (SFMs) G810A/S to vandetanib. Given that current TKIs often lead to resistance, TPX-0046, a next generation RET inhibitor that is structurally differentiated and potent against various mutations, especially SFMs, was designed.
Methods
A series of macrocyclic RET inhibitors were rationally designed and characterized in RET-related biological assays. TPX-0046 was further evaluated in RET-driven tumor models in vivo.
Results
TPX-0046 is a potent and selective next-generation RET/SRC inhibitor with a small and rigid macrocyclic structure that is structurally differentiated from current RET inhibitors. In enzymatic assays, TPX-0046 demonstrated low nanomolar potency against WT and many mutated RETs, as well as SRC, and is VEGFR2-sparing. TPX-0046 potently inhibited RET phosphorylation and cell proliferation in in-house engineered Ba/F3 KIF5B-RET, TT, and LC2/ad cells with IC50s of approximately 1 nM. TPX-0046 is potent against the SFM G810R in Ba/F3 cell proliferation assay with a mean IC50 of 17 nM, whereas comparable proxy molecules for BLU-667 and LOXO-292 have IC50s >500 nM. TPX-0046 demonstrated marked anti-tumor efficacy in vivo in multiple RET-driven cancer cell-derived and patient-derived xenograft tumor models.
Conclusions
TPX-0046 is a novel next generation RET/SRC inhibitor with favorable pharmaceutical properties and possesses potent in vitro and in vivo activity against diverse RET alterations, including the SFM G810R. The novel macrocyclic structure may provide opportunities to overcome treatment resistance from current RET inhibitors. TPX-0046 is currently in IND-enabling studies.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
Turning Point Therapeutics, Inc.
Funding
Turning Point Therapeutics, Inc.
Disclosure
E. Rogers: Shareholder / Stockholder / Stock options, Full / Part-time employment: Turning Point Therapeutics, Inc. D. Zhai: Shareholder / Stockholder / Stock options, Full / Part-time employment: Turning Point Therapeutics, Inc. W. Deng: Shareholder / Stockholder / Stock options, Full / Part-time employment: Turning Point Therapeutics, Inc. X. Zhang: Shareholder / Stockholder / Stock options, Full / Part-time employment: Turning Point Therapeutics, Inc. D. Lee: Shareholder / Stockholder / Stock options, Full / Part-time employment: Turning Point Therapeutics, Inc. J. Ung: Shareholder / Stockholder / Stock options, Full / Part-time employment: Turning Point Therapeutics, Inc. J. Whitten: Shareholder / Stockholder / Stock options, Full / Part-time employment: Turning Point Therapeutics, Inc. H. Zhang: Shareholder / Stockholder / Stock options, Full / Part-time employment: Turning Point Therapeutics, Inc. J. Liu: Shareholder / Stockholder / Stock options, Full / Part-time employment: Turning Point Therapeutics, Inc. T. Hu: Shareholder / Stockholder / Stock options, Full / Part-time employment: Turning Point Therapeutics, Inc. H. Zhuang: Shareholder / Stockholder / Stock options, Full / Part-time employment: Turning Point Therapeutics, Inc. Y. Lu: Shareholder / Stockholder / Stock options, Full / Part-time employment: Turning Point Therapeutics, Inc. Z. Huang: Shareholder / Stockholder / Stock options, Full / Part-time employment: Turning Point Therapeutics, Inc. A. Graber: Shareholder / Stockholder / Stock options, Full / Part-time employment: Turning Point Therapeutics, Inc. Z. Zimmerman: Shareholder / Stockholder / Stock options, Full / Part-time employment: Turning Point Therapeutics, Inc. R. Xin: Shareholder / Stockholder / Stock options, Full / Part-time employment: Turning Point Therapeutics, Inc. J..J. Cui: Leadership role, Travel / Accommodation / Expenses, Shareholder / Stockholder / Stock options, Full / Part-time employment: Turning Point Therapeutics. All other authors have declared no conflicts of interest.
Resources from the same session
920 - Efficacy of intravenous (IV) NEPA, a fixed NK1/5-HT3 receptor antagonist (RA) combination, for prevention of CINV following cisplatin- and anthracycline cyclophosphamide (AC)-based chemotherapy (CT)
Presenter: Lee Schwartzberg
Session: Poster Display session 1
Resources:
Abstract
5146 - Efficacy of olanzapine combination in prevention of nausea & vomiting in highly emetogenic chemotherapy
Presenter: Smitha Saldanha
Session: Poster Display session 1
Resources:
Abstract
1947 - Patient-reported outcome data during real-world use of NEPA for prevention of chemotherapy-induced nausea and vomiting in high-risk platin-receiving patients - A prospective multicenter trial
Presenter: Meinolf Karthaus
Session: Poster Display session 1
Resources:
Abstract
6163 - A study evaluating steroid induced metabolic syndrome after antiemetic dexamethasone therapy in patients received high emetic risk chemotherapy
Presenter: Hee Jun Kim
Session: Poster Display session 1
Resources:
Abstract
2154 - High incidence of nausea during initial and repeated courses if intravenous chemotherapy in patients receiving guideline consistent antiemetic prophylaxis - a prospective, observational, real world study.
Presenter: Teresa Smit
Session: Poster Display session 1
Resources:
Abstract
1637 - "Randomised controlled trial of Scalp Cooling (SC) for the prevention of Chemotherapy Induced Alopecia (CIA)”
Presenter: Jyoti Bajpai
Session: Poster Display session 1
Resources:
Abstract
5351 - Performance of the ‘4S rule’ to predict short-term outcomes in cancer outpatients with unsuspected pulmonary embolism.
Presenter: David Pesántez Coronel
Session: Poster Display session 1
Resources:
Abstract
1189 - Prevalence of venous thromboembolism based on intensive screening for patients with advanced solid tumor in prospective observational study
Presenter: Shota Omori
Session: Poster Display session 1
Resources:
Abstract
4340 - Short-term outcomes of cancer patients with pulmonary embolism according to the setting (hospital-acquired vs. outpatient) at diagnosis.
Presenter: Diego Muñoz Guglielmetti
Session: Poster Display session 1
Resources:
Abstract
4658 - Patient-reported outcomes associated with switching to rivaroxaban for the treatment of venous thromboembolism (VTE) in patients with active cancer
Presenter: Alexander Cohen
Session: Poster Display session 1
Resources:
Abstract