Castle Biosciences (CSTL) investor relations material

Key business drivers and performance

• DecisionDx-Melanoma and TissueCypher tests showed strong performance, with incremental ASP progress and increased physician adoption, leading to raised guidance for the year.

• Melanoma test volume is growing mid to high single digits, with about a third of eligible patients tested and two-thirds of physicians having used the test in the past year.

• The derm sales force remains primarily focused on melanoma, despite a broader dermatology portfolio and some attention to other tests.

• Continued physician education and R&D are expanding the addressable market for melanoma testing, with ongoing efforts to convert new physicians.

• FDA breakthrough designation for the melanoma test is expected to support payer compliance and reimbursement efforts.

TissueCypher growth and market dynamics

• TissueCypher is early in its commercial expansion, with about 15% patient penetration and significant room for growth.

• The test is additive to existing GI risk stratification, identifying at-risk Barrett's esophagus patients who may benefit from more intensive surveillance or intervention.

• Expansion of the sales force and inclusion in two of three major GI society guidelines are expected to support further penetration.

• Medicare patients make up less than half of the volume, with commercial penetration still developing; broader adoption is expected to drive payer coverage.

AdvanceAD-Tx (atopic dermatitis) commercialization

• AdvanceAD-Tx launched in Q4 with strong physician receptivity and doubled order volume off a small base.

• The test addresses a clear clinical need by helping physicians select between biologics and JAK inhibitors, improving patient outcomes and reducing costs.

• Early reimbursement milestones include a recommended fee schedule crosswalk and ongoing efforts to secure Medicare MAC coverage.

• Revenue impact from AdvanceAD-Tx is expected to begin in 2027, with Medicare patients representing 15-20% of the target population.