Castle Biosciences (CSTL) investor relations material

Business overview and recent performance

• Focuses on molecular diagnostics with tests in dermatology and gastroenterology, notably DecisionDx-Melanoma and TissueCypher for Barrett's esophagus.

• Q2 saw strong growth in TissueCypher (63% YoY), with volume expectations raised to 50%-52% annual growth.

• Adjusted gross margins remain among the best in the sector, supporting continued R&D investment.

• No significant changes in 2026 outlook post-Q2; macro environment, especially inflation, remains stable.

TissueCypher growth and market penetration

• Addressable market for TissueCypher is about 415,000 Barrett's esophagus patients annually, with current penetration at 10%-12%, aiming for mid-teens by year-end.

• Growth driven by new clinician adoption and increased use among existing customers; workflow integration is key for broader adoption.

• Practices are beginning to standardize TissueCypher as part of care, which could accelerate growth.

• No lab capacity constraints; lab scaled to stay ahead of demand, supporting up to 60,000 tests.

• Long-term penetration modeled at 60%-65% of the addressable market, based on analogs in other molecular diagnostics.

Commercial and operational updates

• Expanded gastroenterology sales territories in Q2; full productivity expected by 2027 after recent hires.

• New reps typically reach full productivity in about six months.

• Most commercial payers lack formal policies for TissueCypher, but increased utilization is expected to drive coverage.