Castle Biosciences, Inc’s. pipeline atopic dermatitis (AD) test holds the potential to identify a subset of patients with AD who have an increased likelihood to achieve a super response to targeted therapies, indicated by a 90% or greater reduction in Eczema Area and Severity Index (EASI) score (EASI90) at three months.
Assuming successful validation, Castle currently expects to launch its pipeline test by the end of 2025.
Castle has enrolled more than 1,100 patients across 39 active clinical study sites (as of Sept. 30, 2024) for this development and validation study. Follow-up is ongoing with many of these patients, as the Company is assessing response at three months, which is the first typical timepoint for clinicians and patients to determine if the current therapy is effective. Launch strategy planning for the Company’s pipeline test, including selecting the reimbursement pathway, is ongoing.
“It is estimated that there are more than six million patients diagnosed with moderate-to-severe AD in the U.S. seeking treatment annually, and approximately 760,000 of these patients seek systemic treatment,” says Derek Maetzold, President and Chief Executive Officer of Castle Biosciences, in a news release. “Today, once a clinician and patient determine that systemic therapy is needed to control the patient’s AD, a ‘trial-and-error’ treatment cycle begins. This ‘trial-and-error’ approach results in approximately 25% of patients discontinuing their initial systemic therapy. Separately, approximately 50% of patients who stay on their initial therapy have indicators of persistent disease burden.
“Data from our ongoing validation study for our pipeline test suggests we may be able to improve the standard-of-care ‘trial-and-error’ treatment approach by identifying patients who are more likely to achieve a super response to a specific class of therapy based on identification of the immune pathway that is driving their AD. By targeting validation of the test to predict a 90% or greater reduction in disease severity by three months, instead of the traditional standard of 75% reduction, this test provides information on an endpoint used in current drug development that we anticipate will be more relevant for the future (EASI90).
“Using a molecular test to identify the disease-driving immune pathways and to inform the class of drugs a patient could initiate based on increased likelihood of achieving a super response provides a precision medicine tool to increase the number of patients achieving a super response in less time by reducing ‘trial-and-error,’ which may reduce the utilization of healthcare resources.”
