Incidence of abiraterone acetate withdrawal response measured by PSA declines
| Autor: | Rajasree Pia Chowdry, A. Oliver Sartor, Jonathan L. Silberstein, Brian E. Lewis, Elisa M. Ledet |
|---|---|
| Rok vydání: | 2015 |
| Předmět: |
Cancer Research
medicine.medical_specialty Additional Therapy business.industry Incidence (epidemiology) Abiraterone acetate Castrate-resistant prostate cancer Urology urologic and male genital diseases Discontinuation chemistry.chemical_compound Endocrinology Oncology chemistry Internal medicine Medicine In patient Single institution business Hormone |
| Zdroj: | Journal of Clinical Oncology. 33:280-280 |
| ISSN: | 1527-7755 0732-183X |
| DOI: | 10.1200/jco.2015.33.7_suppl.280 |
| Popis: | 280 Background: The anti-androgen withdrawal effect is a well-described phenomenon occurring in patients with castrate resistant prostate cancer (CRPC) after discontinuing anti-androgen therapy. There is limited data on withdrawal responses after newer hormonal therapies such as Abiraterone Acetate (AA). Discontinuation of AA may lead to PSA declines but the frequency remains unclear. The goal of our study was to assess the incidence and duration of PSA decreases after stopping AA. Methods: We reviewed 51 patients with CRPC who had discontinued AA therapy at a single institution (6/2009-6/2014). PSA values were assessed before, during, and after stopping AA therapy. Response was defined as >50% PSA decline post-AA stoppage, with no additional therapy added. Results: From 51 patients treated with AA, only 22 (43%) were eligible for withdrawal response evaluation. A total of 29 patients (57%) were changed to alternate therapies too soon for withdrawal response evaluation. Of the 22 evaluable patients, AA withdrawal was seen in 2 patients (9%). The first patient had a 72% reduction in PSA upon discontinuation of AA, with PSA dropping from 330 (ng/mL) to 93 over 16 days. Previously administered dexamethasone was continued. He had been on AA therapy for 12 months. Time to next treatment was only 1 month so PFS was not ascertainable. The second patient had a 60% reduction in PSA after simultaneously discontinuing both AA and prednisone. His PSA declined from 25.1 to 9.9 over 2 months. He had received only 2 prior months of AA and prednisone and had a clear PSA rise during this therapy. PFS after AA and prednisone discontinuation was 3 months. Time to next treatment was 6 months. Neither patient who responded to AA withdrawal had a prior bicalutamide withdrawal response. Conclusions: PSA response to AA withdrawal is a known, but poorly understood phenomenon that occurs in a subset of patients. Larger studies with longer follow-up are needed to define the incidence of this observation. The potential role of glucocorticoids in this process needs additional elucidation. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|