Background: Despite significant progress, prostate cancer remains a leading cause of death. Cyclin-dependent kinase (CDK) 4/6 inhibitors, which are already approved for the treatment of hormone receptor-positive breast cancer, are undergoing extensive testing as monotherapy and in various combinations as a potentially valuable treatment modality in prostate cancer patients. Thus far, a limited number of these studies have published results, which have been largely disappointing. Areas Covered: In this review, we describe the biologic rationale for the use of CDK4/6 inhibitors in prostate cancer, the existing clinical data describing their use in prostate cancer, and ongoing clinical trials of CDK4/6 inhibitors as monotherapy and in combination for the treatment of prostate cancer. In particular, we focus on possible resistance mechanisms that may be particularly relevant in prostate cancer patients, leading to de novo and acquired resistance, and we highlight novel strategies that can overcome this resistance. Conclusions: Current clinical trials are actively working to (1) refine the role of CDK4/6 inhibitors in prostate cancer patients; (2) develop new inhibitors of other cell-cycle targets, such as CDK2 and CDK7; and (3) explore novel combination therapies with inhibitors of other relevant pathways, such as PI3K or MAPK. Further genomic subtyping of advanced prostate cancer will likely shed light on the subsets of patients most likely to benefit from cell-cycle-targeted agents.

Belzutifan is a hypoxia-inducible factor-2α (HIF-2α) inhibitor that received FDA approval in 2021 for treating cancers resulting from von Hippel-Lindau (VHL) disease, including clear cell renal cell carcinoma (ccRCC), followed by approval in 2023 for sporadic ccRCC that has progressed through multiple lines of therapy. HIF-2α is a promising drug target, as VHL is commonly inactivated in ccRCC, which results in HIF-2α-mediated signaling that is considered central to tumorigenesis. Belzutifan has demonstrated efficacy in clinical trials in the first-line and subsequent line settings, and in combination with tyrosine kinase inhibitors. Despite being overall well tolerated, belzutifan has a distinct safety profile because of its unique mechanism of action. Anemia was the most common adverse event observed in clinical trials and is considered an on-target effect. Hypoxia is also frequently observed and commonly results in dose reductions, treatment discontinuation, and supplemental oxygen use. This review summarizes the rates of hypoxia seen in clinical trials of belzutifan in ccRCC. As the cause of hypoxia is not well understood, this review also discusses possible mechanisms of hypoxia based on preclinical studies of the HIF pathway and HIF-2α inhibitors. Finally, this review proposes monitoring and management recommendations for clinicians prescribing belzutifan to ccRCC patients.

Testing for antibody against hepatitis C virus (anti-HCV) is a low-cost diagnostic method worldwide; however, an optimal screening test for HCV in patients with cancer has not been established. We sought to identify an appropriate screening test for HCV infection in patients with hematologic malignancies and/or hematopoietic cell transplants (HCT). Patients in our center were simultaneously screened using serological (anti-HCV) and molecular (HCV RNA) assays (February 2019–November 2019). In total, 214 patients were enrolled in this study. Three patients (1.4%) were positive for anti-HCV, and 2 (0.9%) were positive for HCV RNA. The overall percentage agreement was 99.5% (95% CI: 97.4–99.9). There were no cases of seronegative HCV virus infection. The positive percentage agreement was 66.7% (95% CI: 20.8–93.9), and the negative percentage agreement was 100.0% (95% CI: 98.2–100.0). Cohen kappa coefficient was 0.80 (95% CI: 0.41–1.00, P < .0001). The diagnostic yield of screening for chronic HCV infection in patients with cancer is similar for serologic and molecular testing.