NEW YORK (Reuters Health) – Personalizing adalimumab treatment for rheumatoid arthritis (RA) patients is likely to be cost-effective, new findings show.
Using clinical response and drug levels (DLs) at six months to determine whether patients should continue taking the drug would result in substantial savings, Dr. Charlotte L. M. Krieckaert of the Jan van Breemen Research Institute in Amsterdam and colleagues found.
“Although specific for patients starting adalimumab treatment, the results underscore the potential merit of personalized biological treatment in RA,” they conclude in the Annals of the Rheumatic Diseases, online November 21.
While current dosing of biologics is based on a “one size fits all” approach, given the variation in pharmacokinetics among patients, “the registered dose is an overtreatment in a substantial proportion of treated patients,” the researchers note. This is a particular concern given the costliness of these medications, they add.
In their own studies, Dr. Krieckaert and colleagues point out, they identified high drug levels (greater than 12 milligrams per liter) in a third of RA patients on adalimumab, which is more than is necessary for clinical benefit.
To investigate whether personalizing treatment based on therapeutic drug monitoring could save money, improve treatment response, and result in fewer adverse events, the researchers developed a model based on an observational study of 272 consecutive RA patients starting adalimumab treatment, as well as data from the Utrecht Rheumatoid Arthritis Cohort.
At six months, the investigators discontinued treatment in patients who had a good to moderate European League Against Rheumatism (EULAR) response to the drug but drug levels below 5 milligrams per liter, based on the assumption that a good clinical response would not be achieved with such low DLs.
Those with drug levels between 5 and 12 ml/L and a good to moderate EULAR response were continued on the drug, while those with higher drug levels who responded to the drug were given the drug once every three weeks instead of once every two weeks.
Patients who did not have a response, but who had appropriate or high drug levels, were switched to another biological with a different mechanism of action, while those with low drug levels and no drug response were switched to a different TNF inhibitor.
The investigators then used a Markov model to estimate quality-adjusted life years (QALYs), costs, and outcomes of the treatment protocol. For the group of patients over a three-year period, they found, the personalized treatment approach would result in a societal incremental cost-effectiveness ratio (ICER) of 666,541 Euros per QALY, while the healthcare ICER was 646,266 Euros per QALY.
The investigators ran 5,000 simulated scenarios, with 72% resulting in cost savings and more QALYs for personalized care, and 28% resulting in cost savings but fewer QALYs.
“Before this algorithm can be implemented in daily clinical practice, the clinical impact of the treatment steps in our algorithm have to be investigated in a randomized clinical trial,” Dr. Krieckaert and her colleagues note. “Results from our scenario analyses suggest that to limit possible QALY loss, using a stricter definition of response (EULAR good response) and stricter cutoffs regarding DL in the algorithm is the way to go.”
Ann Rheum Dis 2013.