Cost effective?
To determine the cost-effectiveness of screening for CYP2D6 and CYP2C19 phenotypes in patients with MDD, the researchers used real-world data to develop a Markov model with a hypothetical cohort of 2000 MDD patients, half of whom underwent pharmacogenetic testing, to determine the potential impact on outcomes over an 18-week period.
The model included the cost of medications and hospitalization, psychiatric counseling, loss of productivity, and the estimated probability of response and adverse events, adjusted for the patient’s likelihood of having a particular metabolizing phenotype.
Results showed that, for CYP2C19, compared to no testing, pharmacogenetic testing would be cost-effective at an incremental cost-effective ratio (ICER) of €60,000 ($64,000 USD) per quality-adjusted life-year (QALY).
This, Squassina said, is “below the willingness to pay threshold” for health authorities in developed countries.
For CYP2D6, pharmacogenetic testing would become cost-effective at an ICER of approximately €47,000 ($40,000 USD) per QALY.
The team plans to complete recruitment and perform a “detailed evaluation of all the variables, especially those relating to the medication history and changes in dosage, and adverse drug reactions.” The researchers would also like to study genetic phenotypes for other metabolizing enzymes and repeat the pharmacoeconomic analysis with the complete dataset.
A glimpse into the future
Approached for comment, Alessandro Serretti, MD, PhD, department of biomedical and neuromotor sciences, University of Bologna (Italy), who was not involved in the study, said the findings show there is a “small but evident benefit” from CYP profiling, “which makes sense.”
He added that in the Netherlands and other European countries, efforts are already underway to record the CYP status of patients at a national level. “Sooner or later, all Western countries will implement it as a routine,” he said in an interview.
He explained that, when such testing is widely available, electronic health record data will allow physicians to immediately select the optimal antidepressant for an individual patient. This will end the current trial-and-error process that leads to delayed treatment and will help avoid serious consequences, such as suicide.
While reducing a single patient’s treatment by a few weeks with the most appropriate antidepressant choice does not make a large difference in the cost per episode, at a population level, it has the potential to make a significant difference.
Dr. Serretti does not envisage genotyping all 333 million Europeans for the CYP phenotype at this point but imagines that in the future, individuals will undergo whole-genome sequencing to determine risks for cancer, dementia, and heart disease, at which point they will also undergo CYP functional allele profiling, and all these data will be recorded on individuals’ EHR.
“So, every doctor, a psychiatrist or cardiologist, can see everything, whenever they need it,” he said.
The study was funded by Fondazione di Sardegna and Regione Autonoma della Sardegna. The authors disclosed no relevant financial relationships.
A version of this article first appeared on Medscape.com.