Recent Autism Test Studies Add to Promising, Yet Inconclusive Research into Psychiatric Diagnostics

Kalorama Information covers in vitro diagnostics (IVD) markets for autism spectrum disorders (ASDs) and other psychiatric disorders in The World Molecular Diagnostics Market, 7thEd.  and Novel Autism Diagnostics.

In two recent studies, in vitro diagnostic (IVD) assays have been investigated that incorporate biomarkers for environmental factors and dysfunctional cellular pathways associated with autism spectrum disorders (ASDs). The accuracy of these oftentimes complex lab tests for ASD has improved with extensive genomic research into the disorder among large groups of ASD-affected families and between ASD and neurotypical siblings. Multiple commercial labs already market ASD testing services, but they are rarely used and are not able to replace diagnostic questionnaires and professional observational assessments. While the clinical utility of a diagnostic lab test for ASD or ASD predisposition would be unquestionably high (particularly in young children and infants), additional research and assay validation across ASD populations is necessary to secure widespread clinical acceptance and payer coverage.

Research in Autism Biomarkers

In a recently published study of 83 ASD-diagnosed subjects and 76 age-matched neurotypical subjects (ASD-negative), a blood-based multiple biomarker test for metabolites and DNA methylation correctly identified approximately 96% of neurotypical subjects and 98% of ASD subjects. Metabolites included in the test were indicative of oxidative stress in detoxification pathways and methylation patterns associated with abnormal genetic regulation. Algorithmic analysis of the multiple analytes was necessary to arrive at the test score of ASD-positive or –negative. Several of the same researchers published a different study in January 2017that tested for toxic metals concentrations in the urine samples of ASD and neurotypical subjects; one analysis was accurate in identifying 85% of neurotypical and 82% of ASD subjects.

The January 2017 urine-sampled metabolite study relied upon a relatively small group of subjects confined to Arizona. The small study groups, both under 150 subjects, did not recruit widely enough to assess the tests across a more representative population for clinically diagnosed ASD.  The geographical concentration of the subjects was significant for the potential disproportionate capturing of genetically predisposed individuals exposed to regional heavy metal contamination. The researchers also did not determine whether abnormal toxic metal excretion was due to high exposure or abnormal glutathione and other detoxification pathways. While biomarkers such as metabolites and heavy metals may be incorporated into future ASD lab assays, the majority of research into autism diagnostics has been focused on the upstream genetics of ASD-associated cellular pathways.  Research assays with high diagnostic utility could also be critical in identifying the most prevalent and effective druggable targets for ASD therapy.

Laboratory Developed Tests (LDTs) for ASD

Currently marketed ASD lab tests have found limited demand due to the unfamiliarity of medical professionals with recently introduced ASD lab testing services and the high costs of multiple-analyte assays with algorithmic analysis (MAAAs), often comparable in cost to gold-standard diagnostic observational exams. Several ASD lab test services also don’t provide official diagnosis, but rather determine genetic predisposition or risk. Major insurers often restrict IVD testing for ASD to children evidencing developmental delays, and do not pay for early testing of infants or young children presumably targeted by autism tests performed by a lab. Most insurers also characterize ASD genetic tests as investigational or experimental and exclude such services from reimbursement (with the notable exception of reimbursed testing for Fragile X Syndrome symptomatically similar to ASDs).

Kalorama Information believes the most significant development for IVD in the area of autism spectrum disorders, other psychiatric disorders and heritable diseases would be the linking of tests and therapies. Pharmacogenetic tests and companion assays co-labeled with specific drugs would be ideal additions to this molecular diagnostics market space that has found only marginal growth in recent years. Payer coverage, physician acceptance and market uptake for many cutting-edge lab tests are dependent upon the availability of applicable therapies or demonstration of clinical utility. Without significant cost differentials or a unique role in clinical decision making, diagnostic tests for psychiatric disorders offer little incremental value over diagnosis based on psychiatric evaluation.