Even when testing drugs in heavily pre-treated patients, clinical trials incorporate subtle biological selection criteria. For instance, the COMPASS trial excludes patients with visceral metastases, a tactic to enrich for a population more likely to respond and avoid the most aggressive disease subtypes.
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The negative ANSA-RAD trial, when contrasted with the positive STAMPEDE trial, demonstrates that patient selection is paramount in adjuvant therapy. The difference in outcomes was driven by risk definition, not the drug. This reinforces that "negative" trials are clinically vital for defining which patient populations do not benefit, preventing widespread overtreatment.
The future of advanced prostate cancer treatment may involve combining ADCs with bispecific T-cell engagers. This strategy could use ADCs for a short duration to deliver a potent hit, followed by immunotherapy to achieve durable remission, potentially reducing toxicity and enabling earlier use.
After years of successfully intensifying hormonal therapy, the focus in prostate cancer is shifting toward de-intensification. Researchers are exploring intermittent therapy for top responders and developing non-hormonal approaches like radioligands to spare patients the chronic, life-altering side effects of permanent castration.
When a highly effective therapy like EV Pembro was approved for 'cisplatin ineligible' patients, the definition of 'ineligible' became very elastic in practice. This demonstrates that when a new treatment is seen as transformative, clinicians find ways to qualify patients, putting pressure on established guidelines.
Developers often test novel agents in late-line settings because the control arm is weaker, increasing the statistical chance of success. However, this strategy may doom effective immunotherapies by testing them in biologically hostile, resistant tumors, masking their true potential.
In the AMPLITUDE trial, only 16% of high-risk metastatic prostate cancer patients received docetaxel, despite it being allowed and indicated by disease characteristics. This suggests a real-world "chemophobia" or physician bias towards newer targeted therapies, even within a clinical trial setting.
The panel suggests AKT inhibitor trials in prostate cancer have been disappointing due to suboptimal biomarker selection (e.g., PTEN IHC). A similar drug in breast cancer showed significant survival benefit when using a more precise NGS-based strategy, indicating a potential path forward if the right patient population is identified genetically.
Three 2025 trials (AMPLITUDE, PSMA-addition, CAPItello) introduced personalized therapy for metastatic hormone-sensitive prostate cancer. However, significant benefits were confined to narrow subgroups, like BRCA-mutated patients. This suggests future success depends on even more stringent patient selection, not broader application of targeted agents.
Experts believe the stark difference in complete response rates (5% vs 30%) between two major ADC trials is likely due to "noise"—variations in patient populations (e.g., more upper tract disease) and stricter central review criteria, rather than a fundamental difference in the therapies' effectiveness.
The successful KEYNOTE-564 trial intentionally used a pragmatic patient selection model based on universally available pathology data like TNM stage and grade. This approach avoids complex, inconsistently applied nomograms, ensuring broader real-world applicability and potentially smoother trial execution compared to studies relying on more niche scoring systems.