KEY TAKEAWAYS
- The REASSURE trial aimed to assess safety outcomes in mCRPC patients treated with Ra-223 subsequent to EBRT in the US.
- The results showed that patients receiving EBRT before Ra-223 did not exhibit a higher incidence of hematological toxicities.
In the Phase 3 ALSYMPCA trial, Ra-223 improved overall survival and safety in metastatic castration-resistant prostate cancer (mCRPC). REASSURE (NCT02141438) is a worldwide observational study of Ra-223 in mCRPC patients in routine clinical settings.
Using data from the second planned interim analysis, A. Oliver Sartor and his team spearheaded the study that aimed to assess the safety outcomes in mCRPC patients receiving Ra-223 after external beam radiation therapy (EBRT) in the US.
In this descriptive analysis (data cutoff: March 20, 2019), patients who received EBRT to the bone before Ra-223 (≤2 years prior to the first Ra-223 dose) were included—results were presented relative to the overall US subset of patients enrolled into REASSURE. The focus of this abstract is on the incidence of hematological toxicities, bone fractures, and second primary malignancies (SPM).
Among the US subset of N=498 patients, 118 received prior EBRT to bone. The median observation duration was 11.7 months for EBRT recipients and 11.9 months overall. Any-grade drug-related hematological treatment-emergent adverse events (TEAEs) were seen in 8% (10/118) and 9% (47/498) of EBRT and overall subset patients, respectively.
Grade ≥3 drug-related hematological TEAEs occurred in 5% (6/118) and 6% (32/498) of EBRT and overall subset patients, respectively. Bone fractures were observed in 7% (8/118) of EBRT patients and 4% (19/498) of the overall subset. Six SPMs occurred in 5/118 EBRT patients (4%), while 11 SPMs occurred in 10/498 overall subset patients (2%). The presentation will include bone fracture events categorized by bone health agent use.
The study’s findings suggested that prior EBRT treatment before Ra-223 administration does not increase the incidence of hematological toxicities compared to the overall US subset. While there appears to be a higher proportion of SPMs and bone fractures among EBRT-treated patients, their actual occurrence remains low in real-world settings. Research was funded by Bayer.
Source: https://meetings.asco.org/abstracts-presentations/230099
Clinical Trial: https://clinicaltrials.gov/study/NCT02141438
Sartor AO, Conti P, Taplin ME, et al. (2024). “Safety outcomes in patients with metastatic castration-resistant prostate cancer treated with radium-223 following external beam radiation therapy: REASSURE US subset.” J Clin Oncol 42, 2024 (suppl 4; abstr 106) 10.1200/JCO.2024.42.4_suppl.106.
