Integrating new evidence about an old drug: authors' reply to Franco et al. and Bell et al

Economic evaluation of the randomised, double-blind, placebo-controlled study of subcutaneous ketamine in the management of chronic cancer pain

Background:

Treating chronic, uncontrolled, cancer pain with subcutaneous ketamine in patients unresponsive to opioids and co-analgesics remains controversial, especially in light of recent evidence demonstrating ketamine does not have net clinical benefit in this setting.

Aim:

To evaluate the cost-effectiveness of subcutaneous ketamine versus placebo in this patient population.

Design and setting:

A within-trial cost-effectiveness analysis of the Australian Palliative Care Clinical Studies Collaborative’s randomised, double-blind, placebo-controlled trial of ketamine was conducted from a healthcare provider perspective. Mean costs and outcomes were estimated from participant-level data over 5 days including positive response, health-related quality of life (HrQOL) measured with the Functional Assessment of Chronic Illness Therapy–Palliative Care (FACIT-Pal), ketamine costs, medication usage and in-patient stays.

Results:

There was no statistically significant difference in responder rates, but higher toxicity and worse HrQOL for ketamine participants (mean change −3.10 (standard error (SE) 1.76), ketamine n = 93; 4.53 (SE 1.38), placebo n = 92). Estimated total mean costs were AU$706 higher per ketamine participant (AU$6608) compared with placebo (AU$5902), attributable to the cost of higher in-patient costs as well as costs of ketamine administration. The results were robust to sensitivity analyses accounting for different medication use costing methods and removal of cost outliers.

Conclusion:

The findings suggest subcutaneous ketamine in conjunction with opioids and standard adjuvant therapy is neither an effective nor cost-effective treatment for refractory pain in advanced cancer patients.

Potential economic impact on hospitalisations of the Palliative Care Clinical Studies Collaborative (PaCCSC) ketamine randomised controlled trial

Objective The aim of the present study was to estimate the potential healthcare cost savings associated with reduced prescribing of subcutaneous ketamine for the treatment of chronic cancer pain after publication of the Palliative Care Clinical Studies Collaborative (PaCCSC) ketamine randomised controlled trial (RCT), to provide further reasons to modify ketamine prescribing practice in this setting. Methods Potential cost savings in this setting were estimated from a health system perspective using a 1-year impact model. The model was populated with estimates derived using an epidemiological approach informed by morbidity and prevalence data, the PaCCSC feasibility study, ketamine RCT and national ketamine utilisation survey results, as well as clinical opinion. Results The total estimated annual hospitalisation costs associated with subcutaneous ketamine prescribing were A$3 899 600 (2605 bed-days). A 17% reduction in ketamine prescribing lowered hospitalisation costs to A$3 236 668 (2162 bed-days), a reduction of A$662 932 (443 bed-days) because of reduced in-patient stays associated with ketamine toxicity and prescribing process. Conclusions The findings from the modelled impact analysis suggest that dissemination of the PaCCSC ketamine RCT results may have saved the Australian healthcare system approximately A$663 000 in annual hospitalisation costs and freed up 443 in-patient bed-days, although there was high uncertainty within the study. Wider dissemination over time and targeted, local de-adoption strategies could result in further savings.