eFFECTOR Therapeutics Presents Phase 1 Data on eFT508, Its Lead Product Candidate, at ASCO 2017

SAN DIEGO, June 5, 2017 – Today, eFFECTOR Therapeutics presented Phase 1 clinical trial data at the 2017 American Society of Clinical Oncology (ASCO) Annual Meeting in Chicago, Illinois. In a poster entitled, “A Phase 1 Dose Escalation Study of eFT508, an Inhibitor of Mitogen-Activated Protein Kinase-Interacting Serine/Threonine Kinase-1 (MNK-1) and MNK-2 in Patients with Advanced Solid Tumors,” eFFECTOR presented data demonstrating that eFT508, the company’s lead product candidate, a selective translation regulator (STR), was well tolerated at doses that produced a level of target inhibition sufficient to maximize anti-tumor activity in preclinical models. Disease stabilization through at least two cycles of therapy (42 days) was seen in four of 11 patients (36 percent) treated at the two highest tolerated doses in this refractory patient population.

“The favorable Phase 1 study data will allow eFFECTOR to rapidly expand our clinical development plans for eFT508, including planned Phase 2 studies of eFT508 as monotherapy and in combination with checkpoint inhibitors later this year,” said Steve Worland, Ph.D., president and chief executive officer of eFFECTOR. “We anticipate that we will have initial Phase 2 efficacy data in 2018 which we believe will support eFT508’s potential to improve immunological treatments for cancer.”

eFT508 is a novel, oral immuno-oncology therapeutic that is a highly selective inhibitor of MNK1/2 kinases that mediate tumor immune evasion and are activated downstream of MEK and MAPK signaling. Previously, eFFECTOR has shown that eFT508 induces anti-tumor immunity and immune memory as a single agent and effectively synergizes with immune checkpoint blockade in vivo in pre-clinical tumor models.

The primary objective of the Phase 1 dose escalation portion of the study was to determine the maximum tolerated dose (MTD) and/or recommended Phase 2 dose of eFT508 in an advanced solid tumor patient population. Secondary objectives were to characterize the safety profile, pharmacokinetic (PK) profile and the effects of eFT508 on pharmacodynamic (PD) markers to establish drug mechanism of action. Common treatment emergent adverse events included nausea, vomiting, constipation, dyspepsia, abdominal pain and fatigue. Dose limiting toxicities included grade 3 nausea, vomiting and tremors at non-tolerated doses. Pharmacodynamic biomarker response has demonstrated target inhibition associated with maximal pre-clinical activity at and below the MTD. The PK profile was characterized by a half-life of approximately 12 hours and minimal accumulation upon repeat dosing. Evaluation of efficacy in Phase 2 studies for both monotherapy and combination with checkpoint inhibitors is planned for patients with advanced solid tumors and lymphoma.

About eFT508

eFT508 is a selective translation regulator and is part of a new class of cancer treatments known as immunotherapies that are designed to harness the body’s own immune system in fighting cancer. eFT508 is a first-in-class, highly potent and selective, oral inhibitor of MNK1 and MNK2. MNK1/2 are terminal kinases in key oncogenic signaling pathways, including KRAS-BRAF-MEK-ERK, and are activated by the mitogen dependent protein kinases (MAPK) in multiple immune cell types. MNK1 and MNK2 integrate MAPK pathway signaling at the level of mRNA translation, resulting in decreased anti-tumor immune activity due to selective upregulation of several immune checkpoint receptors and specific immunosuppressive cytokines. eFT508 selectively blocks MNK1/2 driven mRNA translation promoting anti-tumor immune response.  eFT508 is currently being evaluated in a Phase 1/2 clinical trial in patients with solid tumors (NCT02605083) and in a Phase 1/2 clinical trial in patients with lymphoma (NCT02937675).

About eFFECTOR Therapeutics
eFFECTOR Therapeutics is a clinical-stage biopharmaceutical company pioneering the discovery and development of selective translation regulators as a new class of small molecule therapeutics for cancer. The company’s investigational compounds are designed to restore translational control to halt underlying disease mechanisms while preserving healthy physiological processes. eFFECTOR’s most advanced program focuses on the development of eFT508. The company has additional selective translation regulator programs currently in discovery and development. For more information visit www.effector.com.

Heidi Chokeir, Ph.D.