Factors Associated With Use of Sipuleucel-T to Treat Patients With Advanced Prostate Cancer

Abstract

Importance: Sipuleucel-T is an immunotherapy that has been approved for use in patients with asymptomatic or minimally symptomatic metastatic castration-resistant prostate cancer (mCRPC). However, sipuleucel-T may not be available to some patients because of logistics, cost, and practice structure.

Objective: To identify factors associated with the adoption of sipuleucel-T across the United States.

Design, setting, and participants: In this retrospective cohort study, patients with prostate cancer who received therapy for mCRPC (docetaxel, abiraterone acetate, enzalutamide, cabazitaxel, radium 223, or sipuleucel-T) from January 1, 2010, through June 30, 2016, were identified in a large claims database of commercially insured patients. Patients who received sipuleucel-T were compared with patients who received any of the other treatments for mCRPC but did not receive sipuleucel-T. Data were analyzed from May 3, 2018, to February 24, 2019.

Exposures: Sipuleucel-T treatment.

Main outcomes and measures: Patterns of treatment that involved the use of sipuleucel-T were elucidated, and binomial logistic regression was conducted to determine patient and physician factors that were associated with the use of sipuleucel-T and whether patients received sipuleucel-T in isolation or concurrently with other therapies.

Results: Among 7272 patients who received a treatment for mCRPC, 730 (10.0%) received sipuleucel-T. Mean (SD) age of patients in the entire cohort was 73.2 (9.2) years; 6739 (92.7%) were non-Hispanic and 975 (13.4%) were black. In multivariable analysis, patients who were Hispanic (odds ratio [OR], 0.57; 95% CI, 0.38-0.86) or lived in the Pacific region (OR, 0.66; 95% CI, 0.45-0.97) had lower odds of receiving sipuleucel-T than patients who were not Hispanic or who lived in the South Atlantic region. Patients with higher incomes had greater odds of receiving sipuleucel-T than patients with incomes of less than $50 000 (OR, 1.29 [95% CI, 1.04-1.61] for $50 000-$99 000; OR, 1.43 [95% CI, 1.10-1.85] for >$99 000). Patients treated by a urologist had greater odds of receiving sipuleucel-T than patients not treated by a urologist (OR, 8.89; 95% CI, 7.10-11.11). Sixty-seven patients received concurrent therapies with sipuleucel-T, most commonly abiraterone or enzalutamide, but no factors were independently associated with patients receiving sipuleucel-T concurrent with other therapies for mCRPC.

Conclusions and relevance: In this study, 1 of 10 patients with prostate cancer who were treated for mCRPC received sipuleucel-T, with several variables associated with its use. Identifying disparities in receipt of sipuleucel-T may affect future access to this and other highly specialized cancer therapies by defining barriers to treatment that could be addressed in future studies.

Figure 1.. Diagram of Cohort Selections

A, Cohort 1 included all patients treated with a focus drug. B, Cohort 2 included only those patients from cohort 1 who had continuous prior enrollment.

Figure 2.. Sequence of Concurrent Sipuleucel-T Treatment

Treatment courses for patients identified as receiving sipuleucel-T treatment concurrently with another therapy for metastatic castration-resistant prostate cancer. Each row represents and individual patient.

Figure 3.. Geography of Sipuleucel-T Use

Map of the United States depicts 703 centers across 635 unique zip codes that offer sipuleucel-T. Hawaii and Alaska are part of the Pacific region but are not shown here; each has 1 center. The number of treatment centers is illustrated by the size of the circle; the color of the circle illustrates the region of the country. Numbers denote the numbers of centers per 1 million (mil) people within the region. All known centers are from the website for sipuleucel-T (https://www.provenge.com/).