eFFECTOR Therapeutics Announces Publication of Zotatifin Preclinical Data in Frontiers in Oncology

Study Demonstrates Role of Zotatifin in Blocking Tumor Growth in Receptor Tyrosine Kinase Driven Tumors

SAN DIEGO, Nov. 24, 2021 (GLOBE NEWSWIRE) — eFFECTOR Therapeutics, Inc. (NASDAQ:EFTR), a leader in the development of selective translation regulator inhibitors (“STRIs”) for the treatment of cancer, announced today the publication of data highlighting the anti-tumor potential of zotatifin, the company’s clinical-stage inhibitor of eukaryotic translation initiation factor 4A (“eIF4A”), in the peer-reviewed journal Frontiers in Oncology. eIF4A is a catalytic component of the eIF4F complex, which regulates oncoprotein production at the level of mRNA translation. The published research showed that zotatifin downregulated the expression of certain receptor tyrosine kinases (“RTKs”), which are mutated and overexpressed in many cancers. The research also showed that rational combinations of zotatifin with the PI3K inhibitor alpelisib or the AKT inhibitor ipatasertib, both of which inhibit signaling downstream of RTKs, led to enhanced anti-tumor activity in vivo.

“The preclinical results highlighted in this publication underscore the unique therapeutic advantages of eIF4A inhibition and further demonstrate zotatifin’s potential as a promising clinical strategy for patients with cancers driven by RTK overexpression or dysregulation,” said Steve Worland, Ph.D., president and chief executive officer of eFFECTOR. “These data and other results are informing the selection of biomarker-specific patient populations for the Phase 2a expansion cohorts we initiated earlier this year.”

The Role of eIF4A in Cancer
eIF4A is a strong anti-proliferative target located at the convergence of both the RAS and PI3K signaling pathways. eIF4A inhibition selectively regulates the translation of a distinct set of target “onco” mRNAs that encode a number of important oncoproteins and survival factors. Through eIF4A inhibition, there is potential to target multiple oncoproteins, including those for which there are currently no targeted therapies available, such as MYC and Cyclin D1.

About Zotatifin (eFT226)
Zotatifin is a highly potent and sequence-selective small molecule inhibitor of eIF4A that works by translationally down-regulating expression of select RTKs that contain zotatifin binding motifs in the 5-prime untranslated region (5’-UTR) of their mRNAs. We are currently investigating zotatifin in ongoing clinical trials for solid tumors and as a potential host-directed antiviral therapy in patients with mild to moderative COVID-19 in collaboration with the University of California, San Francisco.

About eFFECTOR Therapeutics
eFFECTOR is a clinical-stage biopharmaceutical company focused on pioneering the development of a new class of oncology drugs referred to as STRIs. eFFECTOR’s STRI product candidates target the eIF4F complex and its activating kinase, mitogen-activated protein kinase interacting kinase (MNK). The eIF4F complex is a central node where two of the most frequently mutated signaling pathways in cancer, the PI3K-AKT and RAS-MEK pathways, converge to activate the translation of select mRNA into proteins that are frequent culprits in key disease-driving processes. Each of eFFECTOR’s product candidates is designed to act on a single protein that drives the expression of multiple functionally related proteins, including oncoproteins and immunosuppressive proteins in T cells, that together control tumor growth, survival and immune evasion. eFFECTOR’s lead product candidate, tomivosertib, is a MNK inhibitor currently being evaluated in KICKSTART, a randomized, double-blind, placebo-controlled Phase 2b trial of tomivosertib in combination with pembrolizumab in patients with metastatic non-small cell lung cancer (NSCLC). Zotatifin, eFFECTOR’s inhibitor of eIF4A, is currently being evaluated in Phase 2a expansion cohorts in certain biomarker-positive solid tumors, including ER+ breast cancer and KRAS-mutant NSCLC. eFFECTOR has a global collaboration with Pfizer to develop inhibitors of a third target, eIF4E. In addition to the company’s oncology focus, zotatifin is being evaluated as a potential host-directed anti-viral therapy in patients with mild to moderate COVID-19 in collaboration with the University of California, San Francisco, under a $5 million grant sponsored by the Defense Advanced Research Projects Agency.

Forward-Looking Statements
eFFECTOR cautions you that statements contained in this press release regarding matters that are not historical facts are forward-looking statements. The forward-looking statements are based on our current beliefs and expectations and include, but are not limited to: the future clinical development of our product candidates; and the potential therapeutic benefits of our product candidates. Actual results may differ from those set forth in this press release due to the risks and uncertainties inherent in our business, including, without limitation: potential delays in the commencement, enrollment and completion of clinical trials; disruption to our operations from the COVID-19 pandemic, including clinical trial and manufacturing delays; our dependence on third parties in connection with product manufacturing, research and preclinical and clinical testing; the results of preclinical studies and early clinical trials are not necessarily predictive of future results; the success of our clinical trials and preclinical studies for our product candidates is uncertain; regulatory developments in the United States and foreign countries; unexpected adverse side effects or inadequate efficacy of our product candidates that may limit their development, regulatory approval and/or commercialization, or may result in recalls or product liability claims; our ability to obtain and maintain intellectual property protection for our product candidates; we may use its capital resources sooner than it expects; and other risks described in our prior filings with the Securities and Exchange Commission (SEC), including under the heading “Risk Factors” in our most recent quarterly report on Form 10-Q and any subsequent filings with the SEC. You are cautioned not to place undue reliance on these forward-looking statements, which speak only as of the date hereof, and we undertake no obligation to update such statements to reflect events that occur or circumstances that exist after the date hereof. All forward-looking statements are qualified in their entirety by this cautionary statement, which is made under the safe harbor provisions of the Private Securities Litigation Reform Act of 1995.

Contacts:
Investors:
Stephanie Carrington
ICR Westwicke
646-277-1282
Stephanie.Carrington@westwicke.com

Media:
Heidi Chokeir, Ph.D.
Canale Communications
619-203-5391
heidi.chokeir@canalecomm.com