The use of eltrombopag, a thrombopoietin receptor agonist, for the perioperative management of immune thrombocytopenia (ITP) appears to be less costly than intravenous immunoglobulin (IVIg) based on a cost-effectiveness analysis conducted from the perspective of the Canadian public health care payer (see TABLE). The findings, which researchers say could help inform policies on drug accessibility, were published in Blood Advances.
The optimal treatment of patients with ITP during the perioperative period is a subject of controversy because IVIg is expensive, resource-intensive, and has been associated with side effects and allergic reactions. Regardless, patients are commonly prescribed IVIg infusion to increase platelet counts before surgery, contributing to shortages of IVIg in Canada and other parts of the world that have led clinicians to search for alternatives.
Researchers led by Feng Xie, PhD, and Donald M. Arnold, MD, both of McMaster University in Ontario, Canada, compared the cost effectiveness of perioperative treatment with IVIg to eltrombopag, which was shown to be noninferior to IVIg in reaching perioperative platelet count targets as part of the Bridging ITP Trial, a multicenter, open-label trial.
The cost effectiveness analysis used data from The Bridging ITP Trial, in which 74 patients were randomized to receive either eltrombopag or IVIg preoperatively. The researchers conducted an intention-to-treat analysis that compared direct cost and effect of eltrombopag versus IVIg from the Canadian health care payer’s perspective during the perioperative period (preoperative day 21 to postoperative day 28). They defined direct cost as expenses directly related to the delivery of care, excluding operational costs (e.g., capital costs, maintenance, administrative salaries), and costs incurred by patients and caregivers (e.g., productivity loss, parking fees). Costs were adjusted to 2020 Canadian dollars. The effectiveness was measured using the treatment success rate.
Considering all medication costs, including non-ITP medications, eltrombopag cost CA$1,101 less per patient than IVIg.
“Eltrombopag appears to be the less expensive option in this situation,” Dr. Arnold said. “That’s not immediately intuitive, especially in health systems like Canada where the cost of IVIg is not apparent to most clinicians.”
The direct cost of eltrombopag – defined as the eltrombopag cost plus the dispensing fee – was CA$166,199. In comparison, the direct cost of IVIg – defined as the cost of nursing time, infusion material, physician visits, immunoglobulin, preparation and dispensing fee, and pre-IVIg infusion medication – was CA$188,660.
The direct cost of the two treatments turned out to be the largest driver of cost in the analysis, accounting for 56% of the total costs of eltrombopag and 64% of the total cost of IVIg. The eltrombopag group also incurred additional costs for rescue IVIg infusions and blood product transfusions (non-IVIg). Higher costs in the IVIg group were associated with the administration of more red blood cell units and platelet transfusions than in the eltrombopag group.
The second largest driver of overall cost was surgery-related cost, which totaled CA$86,147 (29.3%) in the eltrombopag group and CA$77,613 (26.1%) in the IVIg group.
The treatment success rate for eltrombopag – measured as reaching perioperative plate count targets without requiring a second agent – was 78.9%, compared with 61.1% in the IVIg group. Using a cost-effectiveness analysis technique that accounts for both cost and effect, the researchers concluded that eltrombopag was as effective as IVIg, but less costly.
The researchers also performed a series of sensitivity analyses to look at how certain factors could change the value proposition in ITP treatment. For instance, eltrombopag was CA$1,638 less expensive per patient when using the lowest published cost of the drug (CA$1.87 per mg). However, if researchers calculated costs using the highest published cost of eltrombopag (CA$7.03), the cost in the eltrombopag group was CA$7,022 higher per patient than IVIg.
The IVIg dose size was also a factor in the cost effectiveness equation. The researchers found that when 1 g/kg of IVIg was used, 58% of patients in the IVIg group achieved preoperative platelet count targets and eltrombopag was more expensive at CA$562 per patient. However, when 2 g/kg of IVIg was used, 66% in the IVIg group achieved preoperative platelet count targets and IVIg was CA$2,714 more expensive per patient.
Any conflicts of interest declared by the authors can be found in the original article.
Reference
Kaur MN, Arnold DM, Heddle NM, et al. Cost-effectiveness of eltrombopag versus intravenous immunoglobulin for the perioperative management of immune thrombocytopenia [published online ahead of print, 2021 Nov 15]. Blood Adv. doi: 10.1182/bloodadvances.2021005627.
