UK regulator rules against cabazitaxel in prostate cancer
MedWire News: Treatment of hormone-refractory metastatic prostate cancer with cabazitaxel is not a cost-effective use of National Health Service (NHS) resources, say new UK guidelines.
The most recent UK National Institute for Health and Clinical Excellence (NICE) guidance on cabazitaxel is based on the conclusions of an independent appraisal committee who assessed findings from an evidence review group (ERG) from the University of Sheffield.
The ERG examined clinical evidence and a health economic model submitted by cabazitaxel's manufacturer. That evidence was based on the TROPIC trial, in which 755 patients were randomly allocated to receive either cabazitaxel or mitoxantrone, in addition to prednisone or prednisolone.
The trial showed a significant improvement in median overall survival and in progression-free survival with cabazitaxel compared with mitoxantrone, at 15.1 versus 12.7 months and 2.8 versus 1.4 months, respectively.
However, the appraisal committee was concerned about the manufacturer's base-case analysis, which used survival data from a post-hoc subgroup of TROPIC consisting of European patients with an Eastern Cooperative Oncology Group (ECOG) performance status of 0 to 1 who had previously received 225 mg/m2 or more of docetaxel.
"There was no reason why results from patients recruited at TROPIC's centers would differ from those recruited elsewhere," explain Anwar Jilani and colleagues from NICE. "The ERG considered that the appropriate population for this appraisal should include all patients who received 225mg/m2 or more of docetaxel and who had an ECOG performance score of 0 to 1," they write in The Lancet Oncology.
The ERG were also unsure of the manufacturer's modeling of Kaplan-Meir data for extrapolating survival data as "it was specific to the trial population and less generalizable to other populations."
In addition, the utility value used for the disease state was similar to that observed in the age-matched general population, which the committee agreed was implausible. The manufacturer's base-case model estimated an incremental cost-effectiveness ratio (ICER) of £ 74,900 (US$ 118,865; € 93,454) per quality-adjusted life-year (QALY) gained.
However, using survival data specific to its preferred population and using parametric curves, the ERG estimated an ICER of £ 89,476 (US$ 141,997; € 111,641) and in September 2011, the committee concluded that cabazitaxel would not be a cost-effective use of NHS resources.
In response, the manufacturer presented a revised base-case model including an updated utility value for stable disease, the committee's preferred population, and a number of mathematical approaches to extrapolate survival data. This model estimated an ICER of £ 86,008 (US$ 136,493; € 107,314) per QALY.
However, the committee concluded that, of the proposed methods for extrapolating survival data, the pricewise analysis was the most appropriate, which gave an ICER of £ 87,518 (US$ 138,889; € 109,198) per QALY gained for the committee's preferred population.
The committee agreed that cabazitaxel was an effective, life-extending treatment, but that the most plausible ICER exceeded £ 87,500 (US$ 138,523; € 108,409) and the additional weight needed to bring the ICER into the range regarded as a cost-effective use of NHS resources was too great.
Cabazitaxel could therefore not be recommended as an appropriate use of NHS resources, conclude Jilani et al.
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By Sally Robertson