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Castle Bio Adds Data for DecisionDx Melanoma Assay, Eyes Squamous Cell Carcinoma Reimbursement


NEW YORK – Castle Biosciences said this week that it is hoping to grow its dermatological cancer testing business, continuing to build data for its DecisionDx-Melanoma assay and anticipating new payor coverage for its squamous cell carcinoma risk test.

On a call discussing the firm's 2021 financial results this week, Castle CEO Derek Maetzold said that Castle doubled its dermatology commercial team in 2021 after cementing a local coverage determination for the test from the Centers for Medicare and Medicaid Services' MolDx program at the end of 2020.

As a result, the company has grown the test's reach, with what Maetzold said was the addition of approximately 1,900 new ordering clinicians in 2021. However, a significant portion of the market still remains unaddressed.

As it expands its customer base, Castle has been building additional data that it hopes will catalyze further adoption. In January, company researchers presented an initial analysis at the 2022 Winter Clinical Dermatology Conference from a collaboration with the National Cancer Institute and its Surveillance, Epidemiology, and End Results cutaneous melanoma registry program.

In that collaboration, investigators linked DecisionDx-Melanoma test reports for patients in the NCI SEER registries' database, which had recorded their outcomes, specifically overall survival and melanoma-specific survival.

Maetzold cited two main takeaways. As the company has seen in internal retrospective and prospective studies, the real-world outcomes were better for patients with low-risk test scores than for those with high-risk test scores.

Patients who had a low-risk Class I or Class IA test result had a low-risk of progression and likelihood of dying from melanoma or death from all causes, while those with a high-risk Class II or IIB test result had a higher likelihood of dying from melanoma or dying from all causes.

Maetzold called this "a good confirmation that the test performs as it has before," but now in a large, unselected patient population.

While that replication is important "from a standpoint of test reproducibility," he added, a more important takeaway for patients might be that, regardless of what their test result was, those who received DecisionDx Melanoma tests in addition to the traditional clinical pathologic assessment, lived longer than patients whose clinicians relied solely upon traditional risk factors.

"We are looking forward to a full publication of this initial readout, as well as ongoing linkages over the next several years," Maetzold said.

Apart from the SEER study, Maetzold also highlighted results shared at the Winter Clinical Dermatology Conference from a collaborative patient survey performed with the Melanoma Research Foundation. Researchers reported that 90 percent of patients surveyed said they wanted information about their tumors at the time of diagnosis.

"Further, patients who received melanoma testing [reported that] the results were useful to them, and testing gave them increased knowledge, relief from uncertainty, personalized treatment options, and information for life planning," he said.

As it seeks to expand adoption of DecisionDx-Melanoma through outreach and data collection, Maetzold said that Castle is also expecting a major catalyst for its dermatology franchise in an anticipated draft local coverage determination for its squamous cell carcinoma assay, DecisionDx-SCC, by the end of the second quarter.

The company submitted the technical assessment dossier for the test to MolDx in mid-2020, and had initially expected a draft LCD in 2021, with finalization this year. With the timeline for the draft now delayed to this year, Castle is hoping for a finalization "roughly sometime in the first half of 2023."

"We continue to see adoption of the DecisionDx-SCC exceeding our expectations as the unmet clinical need here is significant, and we are proud of the impact our test is having on patient care and will continue to do what we believe is the right thing for our patients, providing test results that impact treatment decisions and improve outcomes," he said.

Castle is also in the midst of integrating its test with what it believes is the most prominently used EMR system in the dermatology community, Modernizing Medicine's MS System.

"It's a system built towards office-based procedures, and as we know, the vast majority of our dermatologists are office-based, private practice individuals. So, that fits their model," Maetzold said.

He added that the company is working to integrate DecisionDx Melanoma into the MS system such that clinicians using the system will be prompted, when treating a patient diagnosed with melanoma, to consider using DecisionDx via a drop-down menu.

"It makes ordering easier. It's a couple of clicks to go ahead and say yes, that they want to order the Castle test. ... That's a smooth system," Maetzold said.

Although the agreement is still nascent, Maetzold said that Castle expects one effect of EMR integration to be that physicians already using DecisionDx-Melanoma for appropriate patients in their practice may be prompted more often during times where their charges would be otherwise overlooked or fall through the cracks.

For clinicians who have already shunned the test, EMR-based prompting is unlikely to change their mind, he added, although Castle hopes to be "proven wrong" on that front, he added.

New targets

Castle also made a significant move in December with the acquisition of Cernostics and its TissueCypher spatial-omics platform, offering an entry into gastroenterology.

The firm is first pursuing a risk stratification test for Barrett's esophagus — an esophageal cancer precursor — but eventually hopes to create a suite of commercial tests for use by a single clinician within the GI franchise.

"Initial response from providers is positive, and with strong execution on our commercial strategy, our team is seeing a promising start in accessing providers," Maetzold said. He added that future expansion could come from internal development or from acquisitions.

Maetzold also gave an update on Castle's inflammatory skin disease test, intended to predict therapy response for patients with psoriasis, atopic dermatitis, and related conditions. "In 2021, we formed our steering committee with leading experts in the field, received IRB approvals, initiated the development and validation study," and enrolled the first of a previously described 4,800 patient cohort, he said.

Maetzold said the company remains on track to launch the test by the end of 2025.