- Design
- Post hoc landmark analysis of two phase 3 trials
- Population
- 564 LATITUDE and 578 ARASENS patients with metastatic hormone-sensitive prostate cancer
- Primary outcome
- Overall survival after testosterone breakthrough >35 ng/dL
- Effect
- LATITUDE HR 1.49 (95% CI 1.07 to 2.08); ARASENS HR 1.18 (95% CI 0.85 to 1.62)
This post hoc analysis looked at the treatment arms of two phase 3 trials in metastatic hormone-sensitive prostate cancer: LATITUDE (abiraterone with prednisone and ADT) and ARASENS (darolutamide with ADT and docetaxel). It asked whether any testosterone reading above 35 ng/dL during treatment was linked to outcomes.
In LATITUDE, breakthrough was associated with worse overall survival (adjusted HR 1.49, 95% CI 1.07 to 2.08) among 564 patients. In ARASENS, among 578 patients, there was no significant association with survival (HR 1.18) or with time to castration resistance.
The authors stress that these are exploratory, within-trial associations. They do not show that breakthrough causes worse outcomes or set a testosterone target.
It is still a reason to check testosterone on treatment. A raised level can reflect missed or late injections, which is a correctable cause.
- Check serum testosterone periodically during ADT-based therapy
- Look for missed or late ADT injections when testosterone is above castrate levels
- Do not change intensified therapy solely on one raised testosterone reading
- The association with survival was seen with abiraterone but not clearly with darolutamide-docetaxel
Why it matters
It suggests that testosterone control still matters even on intensified treatment.
Don't overread it
These post hoc associations do not establish causation or a target testosterone level.
The statistics, in plain English
A hazard ratio of 1.49 means about 49% higher death rate after the landmark in LATITUDE patients with breakthrough. In ARASENS the interval (0.85 to 1.62) crossed 1.0, so no association was shown. Post hoc subgroups like these can find links that do not hold up.
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