Disease Characteristics and Completion of Treatment in Patients With Metastatic Castration-Resistant Prostate Cancer Treated With Radium-223 in an International Early Access Program

Clin Genitourin Cancer. 2019 Oct;17(5):348-355.e5. doi: 10.1016/j.clgc.2019.05.012. Epub 2019 May 31.

Abstract

Background: Radium-223 is approved by the US Food and Drug Administration and European Medicines Agency for the treatment of metastatic castration-resistant prostate cancer (mCRPC). There are currently no markers for selecting patients most likely to complete radium-223 treatment.

Patients and methods: In this phase IIIb, international, single-arm study, patients received radium-223, 55 kBq/kg, every 4 weeks for ≤6 cycles. Primary end points were safety and overall survival. In post hoc analyses patients were grouped according to number of radium-223 injections received (1-4 or 5-6). Associations between baseline covariates and number of injections were investigated.

Results: Of 696 eligible patients, 473 (68%) had received 5 to 6 radium-223 injections and 223 (32%) 1 to 4 injections. Patients with less pain (moderate-severe vs. none-mild, odds ratio [OR], 0.41; P < .0001), lower Eastern Cooperative Oncology Group performance status (≥2 vs. 0-1, OR, 0.51; P = .0074), lower prostate-specific antigen level (>141 μg/L vs. ≤141 μg/L, OR, 0.40; P < .0001), and higher hemoglobin level (<10 g/dL vs. ≥10 g/dL, OR, 0.50; P = .0206) were more likely to receive 5 to 6 than 1 to 4 injections. Median overall survival was not reached and was 6.3 months (95% confidence interval, 5.4-7.4) in patients who had received 5 to 6 and 1 to 4 radium-223 injections, respectively. Adverse events were less common in patients who received 5 to 6 than 1 to 4 injections; anemia was reported in 87 (18%) and 64 (29%) patients, respectively.

Conclusion: Patients with less advanced mCRPC are more likely to receive 5 to 6 radium-223 injections and to achieve better overall survival. Consideration of baseline and disease characteristics is recommended before initiation of radium-223 treatment.

Trial registration: ClinicalTrials.gov NCT01618370.

Keywords: Baseline characteristics; Bone metastases; Injections; Targeted alpha therapy; Treatment completion.

Publication types

  • Clinical Trial, Phase III
  • Multicenter Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Aged, 80 and over
  • Bone Neoplasms / mortality
  • Bone Neoplasms / radiotherapy*
  • Bone Neoplasms / secondary
  • Follow-Up Studies
  • Humans
  • Male
  • Middle Aged
  • Neoplasm Metastasis
  • Prognosis
  • Prospective Studies
  • Prostatic Neoplasms, Castration-Resistant / mortality
  • Prostatic Neoplasms, Castration-Resistant / pathology
  • Prostatic Neoplasms, Castration-Resistant / radiotherapy*
  • Radium / therapeutic use*
  • Survival Rate
  • Treatment Outcome

Substances

  • Radium-223
  • Radium

Associated data

  • ClinicalTrials.gov/NCT01618370
  • EudraCT/2012-000075-16