PGR activation in response to hormonal stimulation induced expression of a HIF reporter system in primary human granulosa cells, with HIF-2 inhibition with the small molecule PT-2385 confirming a HIF-2 contribution to this response...In particular, inflammatory gene expression was dysregulated and a cohort of gonadotrophin-dependent genes, including Pgr, were elevated, suggesting impaired downregulation post-ovulation. These findings provide an important insight into regulation of the hypoxia inducible transcription factors during ovulation and how targeting HIF-2α may be of benefit in future fertility treatments.

By expanding upon the foundation established by belzutifan, the field is poised for further therapeutic advances.

Iron deficiency impairs skeletal muscle regeneration by stabilizing HIF-2α in MuSC, inducing Rb1 RNA expression, and repressing E2F-dependent proliferation. Transient HIF-2α inhibition rescues MuSC proliferation and muscle repair under iron-deficient conditions, highlighting HIF-2α as a potential therapeutic target to counteract sarcopenia in aging and chronic diseases.

Moreover, the combination of H2, silncARSR and PT2385 exerts significantly potentiated efficacy in modulating apoptosis-related protein expression and ultimately enhancing cancer cell mitochondrial apoptosis. The demonstrated high therapeutic efficacy and great biocompatibility of this Hydrogen-PT2385-silncARSR nanocomplex underscore the clinical translation potential for overcoming ccRCC sunitinib resistance.

P1, N=26, Completed, Arrowhead Pharmaceuticals | Phase classification: P1b --> P1

Renal surgery after or during exposure to a HIF-2α antagonist is safe and feasible, with rates of both transfusions and complications commensurate with the reported literature from standard renal surgery. GRs of index renal tumors that eventually needed surgical intervention did not show a significant difference before, during, and after therapy. Tumors exhibiting a positive GR on drug may represent the indication that drives early surgical intervention prior to the tumor reaching the 3 cm threshold. A median washout time of 10 days from last dose of HIF-2α antagonist to surgery was safe and well tolerated.

BMAL1-HIF2α is more sensitive than ARNT-HIF2α is to suppression by PT2399, and the effectiveness of PT2399 for suppressing xenograft tumor growth in vivo depends on the time of day at which it is delivered. Together, these findings indicate that an alternate HIF2α heterodimer containing the circadian partner BMAL1 influences HIF2α activity, growth, and sensitivity to HIF2α antagonist drugs in ccRCC cells.

P3, N=720, Not yet recruiting, Arcus Biosciences, Inc.

AB521 is a potent, selective and orally bioavailable HIF-2α inhibitor, with favourable pharmacological properties, that is being explored clinically for the treatment of ccRCC.

In addressing the treatment of pVHL-deficient tumors, hypoxia-inducible factor 2α (HIF-2α) has risen as a promising therapeutic target, culminating in the development of specific inhibitors like PT2385 and its analogues...Additionally, the safety profile of PMMF showed minimal systemic post-treatment cytotoxicity. In summary, our findings position PMMF as a promising platform for treating tumors with pVHL deficiency and underscore the therapeutic potential of metalloimmunotherapy.

P1, N=14, Recruiting, Arcus Biosciences, Inc.

Here, we investigate HIF-2α and the use of the HIF-2α inhibitor PT2385 to modulate the TME in the immunocompetent GL261 mouse GBM model...Our results show that targeting HIF-2α can switch an immunosuppressive TME towards one that favors a robust and sustained response to ICB based immunotherapy. These findings establish that clinically relevant HIF-2α inhibitors should be explored not only in malignancies with defects in the HIF-2α axis, but also in those exhibiting an immunosuppressive TME that limits immunotherapy responsiveness.