Docetaxel + ADT more cost-effective than abiraterone acetate + ADT for mCSPC

Docetaxel (D) appears to be a more cost-effective than abiraterone acetate (AA) when added to androgen deprivation therapy (ADT) in the treatment of metastatic castration-sensitive prostate cancer (mCSPC) patients in Hong Kong, as reported in a study.

Add-on AA provides greater quality-adjusted life expectancy compared with D, although at a significant cost, according to researchers. “Lowering the price or assessing the noninferior low-dose AA regimen could make ADT + AA more cost-effective.”

The researchers constructed a three-state Markov transition model to project the cost-effectiveness of ADT alone, ADT with abiraterone plus prednisone (ADT + AA), and ADT + D in a hypothetical cohort of 65-year-old men with mCSPC across different health states: from newly diagnosed, progression-free mCSPC to disease progression and death. They used survival data from five randomized controlled trials (CHAARTED, LATITUDE, STAMPEDE [2016/2017], and GETUG-AFU15).

Integrating simulations with probabilistic sensitivity analysis, ADT + D bested ADT alone with 0.79 higher quality-adjusted life-years (QALYs). The incremental cost-effectiveness ratio (ICER) for adding D to ADT was US$ 14,397 per QALY gained, which fell below the threshold for willingness to pay (WTP) in Hong Kong (considered three times of local gross domestic product per capita or US$ 138,649). [Prostate Cancer Prostatic Dis 2020;23:108-115]

In a head-to-head comparison between ADT + D and ADT + AA, patients had better clinical outcomes with the latter with further gains of 0.79 QALY.

“Although currently there is no directly RCT comparing [the two strategies], recent network meta-analyses supported our findings that ADT + AA is a more favourable treatment compared to ADT + D,” the researchers said. [Eur J Cancer 2018;103:78-87; Curr Med Res Opin 2018;34:903-910]

However, the corresponding ICER of using upfront AA was above the WTP threshold at US$ 361,439/QALY.

ADT + D proved more cost-effective in all simulations, while ADT + AA showed an economic advantage only if the cost of AA was reduced by at least 63 percent, as the researchers pointed out. Furthermore, the low-dose AA (250 mg) strategy was cost-effective when it generated equivalent efficacy as the standard dosage (1,000 mg).

“The price of AA is a driving factor to the cost-effectiveness of ADT + AA strategy, given that the price of prednisone attributes <1 percent in the overall cost of AA plus prednisone. Price of AA can be lowered by two means,” according to the researchers.

First is by using a generic equivalent. The availability of generic AAs, which is expected soon given the invalidation of AA patent by the US administrative court in January 2018, should lower the prices by 25 percent in average. Alternatively, a low-dose AA regimen (250 mg daily) may be administered. [JAMA Oncol 2019;5:144-145; Conti RM, Berndt ER. (2014). Specialty drug prices and utilization after loss of U.S. patent exclusivity. Cambridge: National Bureau of Economic Research]

“The current cost-effective analysis should be included in the decision-making process in governments or health authorities to make recommendation regarding the best sequence of therapy for mCSPC patients,” the researchers said.