Investigators who examined the hematologic effects of radium-223 in men with advanced prostate cancer found a higher rate of drug-induced pancytopenia than reported in the literature, according to a new report published in Cureus.

William P. Skelton, MD, of the H. Lee Moffitt Cancer Center in Tampa, Florida, and colleagues studied 22 patients with metastatic castration-resistant prostate cancer (mCRPC) who received radium-223 at the University of Florida Health Shands Hospital in Gainesville. Radium-223 (Xofigo) is a bone-seeking radioactive isotope that emits alpha particle radiation and was approved by the FDA in 2013 for use in men with mCRPC with bone metastases.

Of the 22 patients, 16 (73%) complete the full course of radium-223 treatment (6 doses) and 6 did not. Pancytopenia developed in 10 patients (45%), a rate much higher than the 2% rate found in the pivotal phase 3 ALSYMPCA trial upon which FDA based its approval. The condition resolved in 2 patients within 8 months, whereas cytopenias persisted in the other 8 patients. Older age and higher ECOG score were associated with an increased risk of pancytopenia, according to the investigators.

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“In summary, our results suggest that the possibility and consequences of bone marrow failure in Xofigo may be much more serious and common than previously reported, and should play a larger role in informed consent and shared decision-making,” Dr Skelton and colleagues concluded.


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Reference

Skelton WP, Dibenedetto SW, Pang SS, et al. A single-center retrospective analysis of the effect of radium-223 (Xofigo) on pancytopenia in patients with metastatic castration-resistant prostate cancer. Cureus 12:e6806. doi: 10.7759/cureus.6806