Dr. Park on the Increasing Use of Biomarker Testing and Radiotheranostics in Prostate Cancer

Chandler Park, MD, MSc, FACP, co-director, Genitourinary Clinical Trials at Norton Cancer Institute in Louisville, Kentucky discusses how the emerging field of radiotheranostics and increasing utilization of biomarker testing will improve the treatment of patients with metastatic hormone-sensitive prostate cancer (mHSPC).

Now that the efficacy of PARP inhibitors in BRCA-mutated metastatic castration-resistant prostate cancer (mCRPC) has been well established, current efforts aim to utilize these therapies in mHSPC, according to Park. Research in this space has demonstrated the heterogeneity of metastatic prostate adenocarcinomas, and the subsequent influence of germline and somatic mutations on treatment benefit and selection, Park explains.

Accordingly, all of these patients can benefit from somatic and germline genetic testing. Individuals with certain mutations should then be considered for clinical trials in the mHSPC space, Park adds. The presence of common mutations like BRCA1 and BRCA2 have become indicative of efficacy with current therapeutics; however, novel mutations such as PALB2 are increasingly included in biomarker screening, Park says.

The utilization of radiopharmaceuticals and molecular imaging is also increasing in prostate cancer, Park adds. The phase 3 VISION study (NCT03511664) contributed to this advancement by demonstrating the efficacy of the radioligand Lutetium 177 (¹⁷⁷Lu) PSMA-617 (¹⁷⁷Lu-PSMA-617) as a third-line treatment for patients who progressed to mCRPC on a taxane and aromatase receptor (AR) inhibitor, Park says.

In December 2022, a press release also reported that the phase 3 PSMAfore trial (NCT04689828) of ¹⁷⁷Lu-PSMA-617 met its primary end point of progression-free survival, Park adds. The trial was conducted in patients with mHSPC who had been previously treated with alternate AR-directed therapy before exposure to a taxane-containing regimen. Initial data from this trial will be released in 2023, he notes.

Other studies in the mCRPC space are investigating the use of ¹⁷⁷Lu-PSMA-617 in combination with an AR inhibitor in earlier lines of therapy, Park adds. The agent is also being explored alongside other theragnostic radioligand treatments in mHSPC, Park concludes.