Take Home:
1- Abiraterone acetate (Zytiga) along with Hormone Therapy (ADT) when given to men who are diagnosed with aggressive prostate cancer and who are ADT naïve experience a longer survival advantage than men who just received ADT alone.
2- This data is clear for men with metastatic disease, but there remains some controversy if men who are not metastatic, despite having aggressive prostate cancer, will also benefit from this treatment protocol.
In June of 2015, there was a trial reported at the ASCO meeting that changed the standard of care for men with prostate cancer. The trial, CHAARTED, demonstrated that for men who are newly diagnosed with aggressive, metastatic hormone naive prostate cancer 6 rounds of chemotherapy with Taxotere at diagnosis along with ADT provided them with a significant survival benefit.
Additional studies have shown that the quality of life (QoL) of men taking early chemotherapy was worse for one year, then actually was better when compared to those who did not take early chemotherapy.
At the 2017 ASCO meeting similarly significant, game changing trial results were released from two different trials, STAMPEDE, and LATITUDE.
Like the original data from the CHAARTED trial, the LATITUDE trial and the STAMPEDE trial will also change the standard of care for the treatment of men diagnosed with aggressive prostate cancer.
Results from the phase III LATITUDE trial demonstrated that the addition of abiraterone (Zytiga) plus prednisone to the current standard of care, androgen deprivation therapy (ADT) lowered the risk of death by 38%. The combination of Zytiga and ADT more than doubled median progression-free survival (PFS) to 33 months compared with 14.8 months for men on ADT plus placebo who were newly diagnosed, high-risk metastatic disease (HR, 0.47; 95% CI, 0.39-0.55; P <.0001).
There was also additional, confirmatory information released at the same ASCO meeting from the STAMPEDE trial, which consisted of a broader population of high-risk hormone-naive men including some men with nonmetastatic prostate cancer. The results from this trial showed that the addition of abiraterone (Zytiga) to the standard of care, ADT lowered the relative risk of death by 37% and improved the PFS by 71%.2 The 3-year survival rate was 83% with abiraterone plus standard therapy compared with 76% for standard therapy alone.
According to Sumanta Kumar Pal, MD, a medical oncologist at City of Hope, California, who served as ASCO’s expert commentator during the press-cast, “It is remarkable to see the similarity in survival benefit across the two studies in the metastatic population.”
In his discussion, he said that the LATITUDE data “should immediately reshape our treatment algorithms for prostate cancer, and abiraterone with conventional hormone therapy should become a new standard of care for men with high-risk metastatic prostate cancer.” He said the STAMPEDE data confirm that approach for metastatic patients but that more study is needed to move abiraterone forward for individuals with nonmetastatic disease.”
Holding a contrary opinion was Nicholas James, BSc, MBBS, Ph.D., the lead investigator on the STAMPEDE trial, who said abiraterone plus prednisone improves the standard of care for men with hormone-naive prostate cancer regardless of metastatic disease status.
“Based on the magnitude of clinical benefit, we believe that the upfront care for patients newly diagnosed with advanced prostate cancer should change,” James said in a statement.
The evidence in favor of earlier treatment for men with advanced or metastatic prostate cancer and who have not yet had ADT has been an emerging development in recent years, experts noted at a press conference held at the meeting.
Cancer ABCs wants to call your attention to the fact that both chemotherapies with docetaxel and Zytiga improve survival outcomes in men who are hormone therapy naive and have very aggressive prostate cancer, but they both also come with toxicities, particularly for older men.
How to decide which of these drugs would be a better alternative is unclear. However, it is a positive happening that we now have two alternative treatment possibilities for men with hormone therapy naive aggressive prostate cancer.
In addition, we still need to clarify if non-metastatic men should a be considered candidates for early Zytiga.
References
1. Fizaxi K, Tran N, Fein LE, et al; the LATITUDE investigators. LATITUDE: A phase 3 double-blind, randomized trial of androgen deprivation therapy (ADT) with abiraterone acetate (AA) plus prednisone (P) or placebos (PBOs) in newly diagnosed high-risk metastatic hormone-naïve prostate cancer (mHNPC) patients (pts). J Clin Oncol. 2017;35 (suppl; abstr LBA3).
2. James ND, DeBono JS, Spears MR, et al. Adding abiraterone for men with high-risk prostate cancer (PCa) starting long-term androgen deprivation therapy (ADT): Survival results from STAMPEDE (NCT00268476). J Clin Oncol. 2017;35 (suppl; abstr LBA5003).
3. Sweeney C, Chen Y-H, Carducci MA, et al. Impact on OS with chemohormonal therapy versus hormonal therapy for hormone-sensitive newly metastatic prostate cancer: an ECOG-led phase III randomized trial. J Clin Oncol. 2014;32 (5 suppl; abstr LBA2).
- See more at http://www.onclive.com/conference-coverage/asco-2017/abiraterone-studies-hailed-as-practicechanging-in-newly-diagnosed-metastatic-prostate-cancer?p=2#sthash.Izj9DUb2.dpuf
Joel T. Nowak, MA, MSW wrote this Post. Joel is the CEO/Executive Director of Cancer ABCs. He is a Cancer Thriver diagnosed with 5 primary cancers - Thyroid, Metastatic Prostate, Renal, Melanoma and a rare cancer, Appendiceal Cancer.
