As the second most diagnosed cancer and the sixth leading cause of cancer death among men worldwide, there is still an unmet need for treatments for prostate cancer. While it is usually a slowly progressive disease, 25% of patients will present with or progress to metastatic castration resistant prostate cancer (mCRPC) and 80% will have bone metastases, making treatment even more complicated.
Androgen deprivation therapy (ADT) is the standard of care for metastatic prostate cancer, but when a patient progresses to mCRPC, further hormone therapy or a non-hormonal approach involving additional chemotherapy is the standard treatment. Radium-223, a radioactive isotope that emits low levels of alpha particle radiation, is indicated for treating patients who have mCRPC with symptomatic bone metastases and no known visceral metastatic disease. Because Radium-223 is a “calcium mimetic”, once it is given intravenously it is able to reach the bone and emit low levels of radiation to the bone and limit the damage in the surrounding tissue. However, there is little data on its effect in mCRPC patients who are mildly symptomatic or asymptomatic, though a recent international expanded access program has demonstrated some benefit. It is also unknown whether Radium-223 efficacy can be correlated to AR-V7 mutational status.
Therefore, the EXCAAPE trial was designed as a multicenter, single arm, open-label, non-controlled phase II trial of Radium-223 activity in patients with mCRPC who have experienced asymptomatic progression while on abiraterone acetate or enzalutamide regardless of their AR-V7 status. Patients were treated with Radium 223 at four week-intervals with six intravenous injections. Each patient had a baseline blood sample collected to perform analysis of circulating tumor cells.
The primary endpoint for the trial radiographic progress-free survival (rPFS) as per Prostrate Cancer Working Group 2 criteria. The trial is also exploring rPFS according to AR-V7 status, overall survival, time to first symptomatic skeletal event, and time to prostate-specific antigen progression according to PCWG2 study criteria.
Results for the trial were recently published in the European Journal of Cancer and demonstrated Radium-223 is a reasonable for mCRPC patients who have asymptomatic bone metastases and have progress on novel hormone therapy.
"Our study demonstrates that for those patients with metastatic castrated resistant prostate cancer with only bone involvement and progressing to first line hormonotherapy. Radium 223 can be an option for those patients who are asymptomatic willing to defer chemotherapy for a more advanced stage.” - Dr. Joan Carles Galcerán - PI of the EXCAAPE Study
Discussion with the PI of the study
Dr. Joan Carles Galcerán, medical oncologist in Spain and PI of the study, discusses his work on the EXCAAPE and how he got the idea for the trial.
- How did you come up with the idea?
- What do you think is the importance of the EXCAAPE study?
- How do you think this study could help patients?
Watch the video to find out!