Dual Drug Combination Slows Treatment-Resistant Prostate Cancer by Targeting Two Pathways Simultaneously

University of Michigan researchers have identified a promising drug combination that could help treat the most aggressive forms of prostate cancer. By simultaneously targeting two key cellular pathways, the approach suppresses treatment-resistant tumors more effectively than either drug alone.

Prostate cancer is diagnosed in about one in eight men during their lifetime and is the second-leading cause of cancer-related death among men in the United States. While androgen receptor inhibitors are the main treatment for metastatic prostate cancer, nearly all patients eventually develop resistance.

Some resistant tumors escape treatment through a process called transdifferentiation, where cancer cells lose their glandular characteristics and begin adopting different identities. This transformation is linked to the loss of genes TP53 and RB1.

The researchers found that BET bromodomain inhibitors can interfere with pathways that allow prostate cancer cells to activate alternative identity programs, but these drugs alone did not permanently stop disease progression. DNA methyltransferase inhibitors, known as DNMT inhibitors, can reactivate genes including glandular genes that are switched off during transdifferentiation.

When combined, the two drug classes produced significantly better results. The combination reversed a substantial portion of gene expression changes in the tumors and showed significant reduction in tumor growth even at doses far lower than recommended levels. The drug combination was well tolerated in mouse models.

The findings, published in JCI Insight on August 11, 2026, suggest the strategy could eventually prove relevant to other cancers that undergo transdifferentiation, including lung and pancreatic cancers. DNMT inhibitors are already FDA-approved for other conditions, including blood cancers, which could accelerate the path to clinical trials.

The researchers now aim to determine which specific genes drive the anti-tumor effects and whether biomarkers could identify patients most likely to benefit. They also want to investigate whether transdifferentiation can be prevented before the cellular transformation begins, which would be key to patient survival.