10-Q: Castle Biosciences Reports Q3 Loss Amid Revenue Shifts

Castle Biosciences reported a net loss of $0.5 million in Q3 2025, a significant decline from a $2.3 million net income in Q3 2024, primarily due to a decrease in dermatologic test revenue and increased operating expenses, despite strong growth in non-dermatologic tests.

Summary

• Net revenues for the three months ended September 30, 2025, decreased by 3.2% to $83.0 million, compared to $85.8 million in the same period of 2024.
• Net revenues for the nine months ended September 30, 2025, increased by 4.7% to $257.2 million, compared to $245.8 million in the same period of 2024.
• The company reported a net loss of $0.5 million for Q3 2025, a decrease from a net income of $2.3 million in Q3 2024.
• For the nine months ended September 30, 2025, the net loss was $21.8 million, compared to a net income of $8.7 million in the prior year period.
• Basic earnings per share shifted to a loss of $0.02 for Q3 2025, from a gain of $0.08 in Q3 2024, and a loss of $0.76 for the nine months ended September 30, 2025, from a gain of $0.31 in the prior year period.
• Gross margin percentage decreased to 74.7% for Q3 2025 from 79.2% in Q3 2024, and to 66.8% for the nine months ended September 30, 2025, from 79.3% in the prior year period.
• Total test report volume increased by 3.2% for Q3 2025 and 8.1% for the nine months ended September 30, 2025, compared to the respective prior year periods.
• Dermatologic test report volume increased by 9.0% for Q3 2025 and 7.6% for the nine months ended September 30, 2025.
• TissueCypher test report volume increased significantly by 74.7% for Q3 2025 and 90.5% for the nine months ended September 30, 2025.
• The IDgenetix test offering was discontinued effective May 2025, leading to an accelerated amortization expense of approximately $20.1 million in Q1 2025.
• The company acquired Capsulomics, Inc. in May 2025, recorded as an asset acquisition, with contingent consideration of up to $2.5 million and a developed technology intangible asset valued at $28.2 million.
• Cash and cash equivalents decreased to $85.6 million as of September 30, 2025, from $119.7 million as of December 31, 2024.
• Marketable investment securities increased to $202.0 million as of September 30, 2025, from $173.4 million as of December 31, 2024.
• Construction of the new corporate headquarters in Friendswood, Texas, is ongoing, with $20.8 million in capital expenditures incurred for the nine months ended September 30, 2025, out of an estimated total cost of $44.2 million.
• The $25.0 million line of credit under the 2024 Loan and Security Agreement expired on September 30, 2025, with no draws made.

Sentiment

Score: 4

Explanation: The sentiment is moderately negative due to the significant shift from net income to net loss, substantial decline in gross margin, and the loss of Medicare coverage for a key product (DecisionDx-SCC). While there are positives like strong growth in TissueCypher and a new product launch, the financial deterioration and regulatory challenges for DecisionDx-SCC outweigh these, indicating a challenging period for the company.

Positives

• Non-dermatologic test revenue increased significantly by $13.8 million (Q3) and $36.9 million (9 months), driven by a 74.7% (Q3) and 90.5% (9 months) increase in TissueCypher test report volumes.
• Overall test report volume increased by 3.2% in Q3 2025 and 8.1% for the nine months ended September 30, 2025, indicating continued adoption of tests.
• Dermatologic test report volume increased by 9.0% in Q3 2025 and 7.6% for the nine months ended September 30, 2025, primarily from DecisionDx-Melanoma and DecisionDx-SCC.
• The FDA granted Breakthrough Device designation to the DecisionDx-Melanoma test in July 2025, potentially expediting its development and review.
• The U.S. District Court vacated the FDA's LDT final rule on March 31, 2025, and the FDA rescinded it on September 19, 2025, removing immediate regulatory uncertainty for existing LDTs.
• The company's existing cash and cash equivalents ($85.6 million) and marketable investment securities ($202.0 million) are believed to be sufficient to fund operations for at least the next 12 months.

Negatives

• Net revenues for Q3 2025 decreased by 3.2% compared to Q3 2024, primarily due to a $16.5 million decrease in dermatologic test revenue.
• The company reported a net loss of $0.5 million in Q3 2025 and $21.8 million for the nine months ended September 30, 2025, a significant decline from net income in the prior year periods.
• Gross margin percentage decreased by 4.5% in Q3 2025 and 12.5% for the nine months ended September 30, 2025, primarily due to lower average selling price (ASP) for DecisionDx-SCC and higher operating costs.
• The DecisionDx-SCC test lost Medicare LCD coverage effective April 24, 2025, leading to a lower realized ASP and a significant decrease in dermatologic test revenue.
• The IDgenetix test was discontinued in May 2025 due to operational results not meeting prior expectations, resulting in an accelerated amortization expense of $20.1 million.
• Operating expenses increased significantly, with total operating expenses up 11.3% in Q3 2025 and 22.8% for the nine months ended September 30, 2025.
• Cash and cash equivalents decreased by $34.2 million for the nine months ended September 30, 2025, compared to a decrease of $3.9 million in the prior year period.
• Net cash used in investing activities increased by $13.3 million for the nine months ended September 30, 2025, primarily due to the Capsulomics acquisition and increased property and equipment purchases.
• The $25.0 million line of credit expired on September 30, 2025, without being drawn upon, removing a potential source of liquidity.

Risks

• The company has a history of recurring net losses and negative cash flows, and may be unable to achieve sustained profitability in the future.
• Revenue currently depends primarily on sales from DecisionDx-Melanoma and TissueCypher, with DecisionDx-SCC revenue significantly impacted by the loss of Medicare coverage.
• Unfavorable U.S. and global economic conditions, including ongoing conflicts, economic slowdowns, inflation, and higher interest rates, could adversely affect business, financial condition, results of operations, or cash flows.
• Changes in regulations or the FDA's enforcement discretion for Laboratory Developed Tests (LDTs), or violations of regulations by the company, could adversely affect the business.
• The company may be unable to manage future growth effectively, which could make it difficult to execute its business strategy, particularly with integrating acquisitions and scaling operations.
• Changes in tax laws or regulations, such as the One Big Beautiful Bill Act (OBBBA), could adversely affect the business, cash flow, financial condition, or results of operations.
• A subpoena from the Department of Health and Human Services, Office of Inspector General, concerning claims submitted for payment under federal healthcare programs, could lead to significant liability and harm reputation, with an unpredictable outcome and no estimable loss range at this time.

Future Outlook

The company plans a limited access launch of its AdvanceAD-Tx test in November 2025. It expects expenses to increase substantially over time due to clinical studies, commercialization strategies, new product development, hiring, and capital expenditures. The company believes existing cash, marketable securities, and anticipated revenue will be sufficient to fund operations for at least the next 12 months, but acknowledges that estimates may prove wrong and capital resources could be depleted sooner. Future profitability depends on maintaining Medicare coverage for existing products, successful commercialization of new products, and managing operating expenses.

Management Comments

• We believe our $85.6 million of cash and cash equivalents and $202.0 million of marketable investment securities as of September 30, 2025, and anticipated revenue from our test reports, will be sufficient to meet our cash requirements through at least the 12-month period following the date that these unaudited condensed consolidated financial statements were issued.
• We believe this designation (ADLT status) not only demonstrates our focus on developing and validating innovative tests but also enables our Medicare reimbursement rate to be set, over the long term, by the median private payor rate, which we believe provides a fair exchange of value.
• We believe DecisionDx-UM is the standard of care in the management of newly diagnosed UM in the majority of ocular oncology practices in the United States.
• We continue to believe that changes in FDA's regulatory approach to LDTs will have no material impact on our existing test offerings.
• We believe this designation (Breakthrough Device for DecisionDx-Melanoma) highlights the test's potential to improve melanoma care through individualized prognostic insights.

Industry Context

The diagnostics industry is highly regulated, with ongoing shifts in FDA oversight of Laboratory Developed Tests (LDTs). The recent vacating and rescission of the FDA's LDT final rule creates a period of uncertainty regarding future regulatory requirements, though the company believes it will not materially impact its existing offerings. The market for dermatologic and gastroenterology diagnostics continues to evolve, with a focus on personalized, clinically actionable information. The company's investment in new tests like AdvanceAD-Tx for atopic dermatitis positions it in a large potential market, while the discontinuation of IDgenetix reflects the competitive and performance-driven nature of the pharmacogenomics space.

Comparison to Industry Standards

• The company's DecisionDx-Melanoma, DecisionDx-SCC, TissueCypher, MyPath Melanoma, and DecisionDx-UM tests have all been granted Advanced Diagnostic Laboratory Test (ADLT) status by CMS, indicating they provide new clinical diagnostic information not available from other tests, a strong competitive differentiator.
• The DecisionDx-UM test is considered the standard of care in the management of newly diagnosed uveal melanoma in most ocular oncology practices in the U.S., suggesting strong market acceptance and clinical utility compared to other diagnostic options.
• The company's gross margin percentage of 66.8% for the nine months ended September 30, 2025, while lower than the prior year, should be evaluated against industry benchmarks for molecular diagnostics, which can vary widely based on test complexity, reimbursement rates, and operational scale. Specific comparable companies or projects are not detailed in the filing to provide a direct benchmark.

Management Changes

Corporate Governance

Legal Proceedings

• Received a subpoena from the Department of Health and Human Services, Office of Inspector General, on February 1, 2024, seeking documents and information concerning claims submitted for payment under federal healthcare programs from January 1, 2015, through February 1, 2024. The company is cooperating but cannot predict the outcome or estimate the amount or range of loss, if any.

Stakeholder Impact

• **Shareholders:** Experienced a significant net loss and decreased EPS, along with a decline in gross margin, which could negatively impact stock price. Dilution risk from increased shares available under the Inducement Plan and potential future capital raises.
• **Employees:** Increased headcount and personnel costs reflect growth, but the discontinuation of the IDgenetix test may have impacted employees in that segment. Stock-based compensation remains a material component of overall compensation.
• **Customers (Clinicians/Patients):** Continued growth in test volumes for TissueCypher and dermatologic tests indicates ongoing adoption. The FDA Breakthrough Device designation for DecisionDx-Melanoma could enhance its perceived value. However, the loss of Medicare coverage for DecisionDx-SCC may affect access or cost for some patients.
• **Payors (Medicare/Commercial Insurers):** The loss of Medicare LCD coverage for DecisionDx-SCC directly impacts reimbursement and revenue from this test. The company is actively seeking reconsideration, indicating ongoing engagement with payors.
• **Suppliers/Creditors:** The company maintains a strong cash and marketable securities position, suggesting continued ability to meet obligations. The extension of the interest-only period on the term loan provides financial flexibility.

Next Steps

• Launch AdvanceAD-Tx (non-invasive GEP test for atopic dermatitis) in a limited access capacity in November 2025.
• Continue to cooperate with the Department of Health and Human Services, Office of Inspector General, in responding to the subpoena.
• Pursue reconsideration requests for both the Novitas and MolDX LCDs regarding DecisionDx-SCC coverage.
• Continue construction of the new corporate headquarters in Friendswood, Texas, with expected completion in early 2026.
• Invest in R&D activities to generate evidence for current and future product candidates and develop new products.
• Expand commercialization strategy for current and future products.
• Hire additional scientific, R&D, operational, financial, and management personnel to support business growth.

Key Dates

Recommendation

The company faces significant headwinds, primarily the shift to a net loss and the loss of Medicare coverage for its DecisionDx-SCC test, which has materially impacted dermatologic test revenue and gross margin. While strong growth in TissueCypher and the FDA Breakthrough Device designation for DecisionDx-Melanoma are positive, the overall financial performance has deteriorated. The expiration of the line of credit and ongoing legal proceedings add to uncertainty. An investor should hold to monitor the outcome of the DecisionDx-SCC reimbursement reconsideration, the successful launch and adoption of AdvanceAD-Tx, and the company's ability to return to profitability and improve gross margins in the face of increased operating expenses and macroeconomic challenges.

Keywords

Molecular Diagnostics, Dermatologic Cancers, Barrett's Esophagus, Uveal Melanoma, Gene Expression Profile, TissueCypher, DecisionDx-Melanoma, DecisionDx-SCC, Medicare Reimbursement, FDA Regulation, LDTs, Financial Performance, Q3 2025, SEC Filing, Biotechnology