作者与单位 Authors & Affiliations
Weiyu Zhang, Kathryn Bieging-Rolett, Ashley LaCayo, Ben Harrison, Jeremy Drees, Crissy Dudgeon, Nandita Bose, Eric S. Lightcap
HiberCell, Roseville, MN
摘要 Abstract
Current standards of care for metastatic clear cell renal cell carcinoma (ccRCC) include immune checkpoint inhibitors (ICIs), VEGFR-tyrosine kinase inhibitors (VEGFR-TKIs), or the combination of both. Recently, the HIF-2alpha inhibitor belzutifan was approved for 2L+ metastatic ccRCC patients and its combination with ICIs or VEGFR-TKIs is being studied in clinical trials. Despite the initial efficacy of these SOCs, most patients eventually relapse. Relapse after VEGFR-TKIs can be due to diverse mechanisms such as activation of non-VEGF angiogenic pathways, stromal remodeling, apoptosis evasion, and HIF upregulation. Therefore, novel therapeutic approaches are needed. HiberCell has developed HC-7366, a GCN2 activator that initiates the integrated stress response, leading to translation inhibition, cell-cycle arrest, HIF-1alpha suppression, and apoptosis in cancer cells. Based on these effects, we explored the potential of HC-7366 to overcome resistance to VEGFR-TKIs in RCC models. In the 786-O ccRCC xenograft model, HC-7366 treatment at multiple doses corresponding to exposures below the MTD in humans yielded robust combination efficacy with either cabozantinib or lenvatinib. HC-7366 alone achieved 63% tumor growth inhibition (TGI), whereas cabozantinib alone induced 30% regression (1/8 PR) and lenvatinib alone produced 95% TGI. When combined, HC-7366 significantly enhanced responses, achieving 71% regression with cabozantinib and 44% regression with lenvatinib (7/8 and 2/8 PRs, respectively). The combination of belzutifan and VEGFR-TKI was inferior to the HC-7366/VEGFR-TKI doublet, with only 36% regression (1 PR) for lenvatinib/belzutifan and 53% regression (5/8 PRs) for cabozantinib/belzutifan. The triplet combination using HC-7366/belzutifan/VEGFR-TKI was more beneficial than any doublet, further improving TGI and responses. Furthermore, in a single mouse trial of 10 RCC PDX models, addition of HC-7366 to axitinib improved outcomes in 8/10 PDX models and was superior to the belzutifan/axitinib doublet in multiple models. Analysis of xenografts showed the combination of HC-7366 and lenvatinib reduced HIF signaling and broadly suppressed cell cycle, growth factor, and angiogenic signaling while simultaneously inducing pro-apoptotic pathways. Our data reveal that combination of HC-7366 with any VEGFR-TKI may be an effective treatment strategy for RCC patients and has the potential to be superior to a VEGFR-TKI/HIF-2 inhibitor combination. A phase 1b clinical trial is now ongoing to evaluate the safety, tolerability, and efficacy of both HC-7366/belzutifan and HC-7366/cabozantinib doublets in metastatic ccRCC (NCT06234605). These results will form a foundation for future evaluation of triplet combinations that integrate HC-7366, VEGFR-TKIs, and HIF-2 inhibitors.