The results of the Steroids in Eosinophil Negative Asthma (SIENA) trial emphasize the importance of a personalized approach to the treatment of asthma. For a given condition, there are likely many different subtypes of patients who may respond differently to different medications. In this case, asthma patients with low vs high sputum eosinophil levels have been identified as two subtypes – however, sputum eosinophil level is not currently a test that is performed on a routine basis. Another limitation of this study is that the difference in response between the two subgroups was mostly driven by the surrogate marker FEV1, which does not always correlate with clinical outcome differences. In addition, there still needs to be larger trials to identify which treatment options will be effective for these subgroups of patients.
Our TreatGx software does not address diagnosis as the software is meant to be used for precision prescribing once the diagnosis is established and medical therapy is deemed necessary. The software does try to personalized drug therapy as much as possible based on patient- and condition-specific variables that have been shown in replicated studies to affect treatment outcomes. If sputum eosinophil level testing becomes more mainstream and is shown in future studies to affect treatment outcomes with ICS or LAAC, eosinophil levels may be added to our TreatGx asthma treatment algorithm in the same way that other lab results are included in other algorithms.
In the meantime, we have critically evaluated guidelines, clinical trials, and other sources of information in order to offer the most evidence-based treatments for asthma in adults. At each stage of treatment escalation for asthma beyond use of a SABA, there is always an option to add a medication or increase the ICS dose – it is up to the prescriber to assess the patient for response and determine which treatment to adjust or add.
A genetic marker to predict sputum eosinophil levels may eventually be found, but to our knowledge, there is not currently a validated genetic test for this. For asthma, there is a pharmacogenetic marker in PharmGKB with level 2A evidence for salbutamol or salmeterol response in children (ADRB2) which we do incorporate into the TreatGx asthma treatment algorithm.