PETRA PI3K Program


  • PETRA 06 applies learnings from Dr. Cantley’s laboratory and focuses on the combination of our alpha-specific PI3K inhibitor serabelisib and a sodium-glucose co-transporter 2 (SGLT2) inhibitor that together have the potential to substantially increase the anti-tumor activity of PI3K inhibitors.
  • Petra plans to initiate a Phase 1b/2 study this year focused on patients with advanced PIK3CA-mutated solid tumors.


  • PETRA 03 includes mutant-specific PI3K inhibitors with selectivity for common mutants over wild-type PI3K, avoiding the glucose/insulin feedback loop.
  • While controlling glucose/insulin feedback loop is highly desirable, avoiding the glucose/insulin feedback loop may be optimal
  • Petra is pioneering a novel approach to selectively target the mutant forms of PI3K



  • Petra has developed highly potent, selective, and drug-like inhibitors of PIP4K2 enzymes, targeting late-stage autophagy
  • Autophagy is a recycling feature that enables the progression and survival of established tumors
  • Autophagy  protects tumor from therapeutic stresses such as chemotherapy and radiotherapy and many tumors appear to be autophagy-dependent, meaning that their survival is dependent on their ability to use the autophagy pathway as a source of nutrient replenishment. [Chude CI, Amaravadi RK. Targeting Autophagy in Cancer: Update on Clinical Trials and Novel Inhibitors. Int J Mol Sci. 2017;18(6):1279. ]
  • Inhibition of late-stage autophagy deprives certain tumor cells of their nourishment and their ability to withstand metabolic or therapeutic stress

  • Many cell lines and freshly isolated human hematologic cancers display a high rate of sensitivity to PIP4K2 inhibitors
  • PIP4K2 inhibitors are active in xenograft studies, demonstrating potent regression in tumor growth and well tolerated beyond efficacious doses
  • Several solid tumors cell lines are also sensitive to PIP4K2 inhibition
  • The initial focus of clinical development of Petra’s PIP4K2 inhibitors will be on patients with hematologic malignancies

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