Clinical Value, Cost Considerations of Abiraterone Acetate, Enzalutamide in Prostate Cancer

02/06/18

A study to be presented at the 2018 ASCO Genitourinary Cancers Symposium (February 8-10, 2018; San Francisco, CA) applied the ASCO Value Framework and ESMO Magnitude of Clinical Benefit Scale (MCBS) to assess the value of abiraterone acetate and enzalutamide in advanced prostate cancer.

Prior research has shown that abiraterone acetate and enzalutamide improve overall survival (OS) in metastatic castration-resistant prostate cancer. Abiraterone acetate is also effective in the metastatic castration-sensitive disease setting. However, the cost implications of earlier treatment versus clinical benefit for these therapies are a concern for many clinicians.

A group of researchers from various institutions in Canada conducted a study aimed at quantifying and comparing the clinical value of abiraterone acetate and enzalutamide and their associated costs in both the castration-resistant and castration-sensitive prostate cancer settings. A total of six randomized phase III trials of abiraterone acetate and enzalutamide were sampled. The ASCO Value Framework version 2 (range < 180) and ESMO MCBS version 1.1 (range, 1-5) were utilized to quantify net clinical benefit. Both resources were used to consider OS, progression-free survival, and quality of life.

Incremental cancer drug costs were also calculated by using average wholesale price and the trials’ reported duration of treatment.

The below table reflects the results of the analysis:

Setting

Trial

Experimental

ASCO Value Score

ESMO MCBS

Monthly Drug Cost (United States Dollars)

Duration of Treatment (months)

Incremental Cancer Drug Cost

Castration-resistance, post-chemo

COU-AA-301

Abiraterone acetate + prednisone + ADT

35.4

5

$11,657.83

7.2

$83,460.94

Castration-resistance, post-chemo

AFFIRM

Enzalutamide + ADT

42.6

4

$12,769.06

8.0

$102,564.40

Castration-resistant, pre-chemo

COU-AA-302

Abiraterone acetate + prednisone + ADT

41.9

3

$11,657.83

13.4

$155,632.73

Castration-resistant, pre-chemo

PREVAIL

Enzalutamide + ADT

36.4

3

$12,769.06

16.1

$205,128.85

Castration-sensitive, ADT

Latitude

Abiraterone acetate + prednisone + ADT

70.4

3

$12,830.15

31.9

$392,896.68

Castration-sensitive, ADT

STAMPEDE

Abiraterone acetate + prednisone + ADT

33.3

4

$12,830.15

42.5

$510,938.62


Researchers concluded that abiraterone acetate and enzalutamide administered in early metastatic castration-sensitive prostate cancer do not provide consistent increases in net clinical benefit compared to castration-resistant disease, but they do incur exponential cost considerations. Alternatives that provide similar net clinical benefit at less incremental costs, such as chemotherapy, warrant major consideration for clinicians and patients.

“Until more information is available to define the optimal sequencing of abiraterone acetate, enzalutamide, and other treatment modalities, current cost implications may hinder moving these agents to earlier treatment settings,” they wrote.—Zachary Bessette

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