May 7, 2020



South San Francisco, CA – May 7, 2020 - Tempest Therapeutics, Inc., a clinical-stage oncology company developing first-in-class therapeutics that combine both precision and immune-mediated mechanisms, today announced the first patient dosed in the Phase 1 clinical trial of TPST-1495, a selective antagonist of both EP2 and EP4 prostaglandin receptors, initially as a single agent and in combination with pembrolizumab in patients with advanced solid tumors.

“We are excited to initiate this trial to evaluate TPST-1495 as a potential treatment for patients with solid tumors,” said Tom Dubensky, Ph.D., chief executive officer of Tempest. “Prostaglandins drive diverse malignancies, and TPST-1495 is a differentiated molecule that blocks both EP2 and EP4 receptor signaling to the exclusion of the EP1 and EP3 receptors, which are beneficial for functional immunity. We believe that given its unique properties, TPST-1495 has the potential to translate into benefit for patients.”

The multicenter, open-label, Phase 1a/1b dose-escalation trial will be conducted at up to six sites across the U.S. The trial will assess the safety, tolerability, pharmacokinetics, pharmacodynamics, and preliminary anti-tumor activity of TPST-1495 as a monotherapy and in combination with pembrolizumab. Following completion of the dose escalation phase, additional patients will be enrolled in an expansion cohort at the maximum tolerated dose. Although the clinical trial will allow participation of patients with any solid tumor histology, Tempest intends to focus evaluation of TPST-1495 in patients with microsatellite stable colorectal cancer (MSS CRC), a prostaglandin-driven malignancy with high levels of EP2 and EP4 receptor expression. For additional information about the study, please visit, identifier NCT04344795.

About TPST-1495

TPST-1495 is an orally available potent small molecule designed to block the receptors EP2 and EP4 in the prostaglandin pathway, which promote both tumor growth and the proliferation of suppressive immune cell populations. Tempest has conducted multiple IND-enabling studies with peripheral blood mononuclear cells (PBMCs) from healthy adult donors and in several mouse tumor models that demonstrate a significant increase in immune activitation and anti-tumor potency by inhibiting both EP2 and EP4, when compared to EP4-only targeted molecules in clinical development. Several malignancies are thought to be prostaglandin driven, including bladder, breast, endometrial, and cervical cancers, in addition to MSS CRC.

About Tempest Therapeutics

Tempest Therapeutics is a clinical-stage oncology company advancing small molecules that combine both precision and immune-mediated mechanisms to modulate anti-tumor pathways with the potential to target a wide range of tumors. The company’s two novel clinical programs are TPST-1120 and TPST-1495, antagonists of PPARα and EP2/4, respectively. Both TPST-1120 and TPST-1495 are progressing through Phase 1 studies, and the company plans to study both agents as monotherapies and in combination with other approved agents in the same malignancies. Tempest is also developing an orally available small molecule inhibitor of TREX-1, an exonuclease highly expressed in tumors that suppresses both STING activation and development of tumor immunity. Tempest is headquartered in South San Francisco and supported by notable healthcare investors. More information about Tempest can be found on the company’s website at

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Sylvia Wheeler

Alex Santos