A recent analysis from the S9346 Phase 3 trial reaffirms that continuous androgen deprivation therapy (CAD) outperforms intermittent ADT (IAD) in metastatic hormone-sensitive prostate cancer (mHSPC), even for patients who achieve a strong PSA response after initial treatment.

The study evaluated 1,523 men with mHSPC who had PSA ≤ 4.0 ng/mL after 7 months of ADT plus bicalutamide. They were categorized into two response groups:

• Complete responders (CR): PSA ≤ 0.2 ng/mL
• Partial responders (PR): PSA 0.3 – 4.0 ng/mL

About 63% of patients in both the IAD and CAD arms achieved CR, while 37% had PR. Complete PSA response was strongly linked to better survival, with CR patients having a 43% lower risk of death compared to PR patients (HR 0.57, p<0.0001). However, when comparing IAD vs. CAD, intermittent therapy consistently performed worse, regardless of PSA response or disease extent. In both CR and PR groups, IAD was associated with a 15% higher risk of death compared to CAD (HR ~1.15). Extensive disease further worsened survival (HR 1.3).

These findings confirm that continuous ADT remains the superior approach, even for patients with favorable PSA responses, and highlight that de-intensification strategies like IAD should not be considered optimal for mHSPC treatment.

Source.