From the Research
A reasonable expectation for PSA reduction after 30 days of combined ADT and apalutamide (Erleada) therapy with a starting PSA of 0.2 ng/mL would be a decline of approximately 80-90%, resulting in a PSA level around 0.02-0.04 ng/mL. This rapid response occurs because ADT blocks testosterone production while apalutamide directly inhibits androgen receptors, creating a powerful dual blockade of androgen signaling that prostate cancer cells depend on for growth. The PSA decline is typically most dramatic in the first month of therapy, with most patients experiencing significant reductions within 2-4 weeks of starting treatment, as seen in studies such as 1 and 2. However, individual responses can vary based on factors such as tumor biology, disease burden, and prior treatments. Some patients may achieve an undetectable PSA (<0.01 ng/mL) within this timeframe, while others might show a more gradual decline. Regular PSA monitoring should continue throughout treatment, typically every 1-3 months initially, to ensure the therapy is working effectively and to establish a new baseline. If the PSA does not decline significantly within the first month, further evaluation may be warranted to assess for potential treatment resistance or non-compliance, as suggested by the findings of 3 and 4. Key factors influencing the rate and extent of PSA reduction include the specific characteristics of the patient's prostate cancer, the presence of metastases, and the patient's overall health status, as discussed in 5. Given the most recent and highest quality evidence from 2, which demonstrates the efficacy of apalutamide in combination with ADT in achieving deep and rapid PSA declines, it is reasonable to expect a significant reduction in PSA levels within the first 30 days of treatment.