CTMX Stock: Insider Activity, Filings & Research
CytomX Therapeutics, Inc. (CTMX) — Drillr’s hub for CTMX insider activity, SEC filings, earnings signals and AI research. Over the trailing 3 months, CTMX insiders filed 0 open-market buys and 4 sales (SEC Form 4).
CTMX insider trading activity (SEC Form 4)
| Date | Insider | Type | Shares | Price |
|---|---|---|---|---|
| Mar 19, 2026 | BELVIN MARCIAofficer: SVP, Chief Scientific Officer | Sell | 31,492 | $6.42 |
| Mar 19, 2026 | McCarthy Sean A.director, officer: CEO | Sell | 118,969 | $6.42 |
| Mar 19, 2026 | Ogden Christopherofficer: Chief Financial Officer | Sell | 19,323 | $6.42 |
| Mar 19, 2026 | Chu Yu-Wayeofficer: Chief Medical Officer | Sell | 21,279 | $6.42 |
| Feb 4, 2026 | Chu Yu-Wayeofficer: Chief Medical Officer | Grant | 75,000 | — |
| Feb 4, 2026 | McCarthy Sean A.director, officer: CEO | Grant | 210,000 | — |
| Feb 4, 2026 | BELVIN MARCIAofficer: SVP, Chief Scientific Officer | Grant | 60,000 | — |
| Feb 4, 2026 | Chu Yu-Wayeofficer: Chief Medical Officer | Grant | 300,000 | $6.09 |
| Feb 4, 2026 | McCarthy Sean A.director, officer: CEO | Grant | 980,000 | $6.09 |
| Feb 4, 2026 | Ogden Christopherofficer: Chief Financial Officer | Grant | 90,000 | — |
| Feb 4, 2026 | Lester Rachaelofficer: Chief Business Officer | Grant | 50,000 | $6.09 |
| Feb 4, 2026 | Lester Rachaelofficer: Chief Business Officer | Grant | 20,000 | — |
| Feb 4, 2026 | Ogden Christopherofficer: Chief Financial Officer | Grant | 325,000 | $6.09 |
| Feb 4, 2026 | BELVIN MARCIAofficer: SVP, Chief Scientific Officer | Grant | 250,000 | $6.09 |
| Nov 10, 2025 | McCarthy Sean A.director, officer: CEO | Sell | 101,793 | $4.54 |
Source: CTMX SEC Form 4 filings, latest Mar 19, 2026. For informational purposes only — not investment advice.
CytomX Therapeutics, Inc. company profile
Overview
CytomX Therapeutics, Inc. (NASDAQ:CTMX) is an oncology-focused biopharmaceutical company founded in 2008 and headquartered in South San Francisco, California. The company went public in October 2015 and has developed a proprietary technology platform called Probody therapeutics for creating conditionally activated cancer treatments. CytomX operates primarily as a research and development organization, advancing both internal drug candidates and partnered programs with major pharmaceutical companies including Bristol-Myers Squibb, Amgen, Astellas, and others.
Business
CytomX operates in the biotechnology sector, specifically focusing on developing next-generation cancer therapies using its proprietary Probody technology platform. This platform creates "masked" therapeutic antibodies that are designed to be activated only in the tumor microenvironment, potentially reducing side effects while maintaining or enhancing anti-cancer efficacy. The company's core technology addresses a fundamental challenge in cancer treatment: how to deliver potent therapeutics specifically to tumors while minimizing damage to healthy tissues. Traditional cancer therapies often cause significant side effects because they cannot distinguish between cancerous and normal cells. Probody therapeutics are engineered with a "mask" that covers the active portion of the antibody until it encounters specific conditions found in tumors, such as certain enzymes or pH levels. CytomX develops several types of Probody therapeutics: 1. Antibody Drug Conjugates (ADCs): These combine antibodies with potent cytotoxic drugs. The company's lead internal program is CX-2051, which targets EPCAM (epithelial cell adhesion molecule) for treating colorectal cancer. 2. T-cell Engagers: These bispecific antibodies simultaneously bind to cancer cells and immune T-cells, directing the immune system to attack tumors. CX-904, developed with Amgen, targets EGFR (epidermal growth factor receptor) and has shown promising results in pancreatic cancer. 3. Cytokine Therapeutics: CX-801 is a masked interferon alpha-2b designed to stimulate immune responses specifically within tumors. 4. Immune Checkpoint Inhibitors: The company has developed masked versions of CTLA-4 inhibitors in partnership with Bristol-Myers Squibb. The company generates revenue through multiple streams: upfront payments, milestone payments, and royalties from pharmaceutical partnerships, which typically account for the majority of annual revenue. Internal programs are in various stages of clinical development and do not yet generate product sales revenue.
Revenue model
CytomX operates a hybrid business model combining internal drug development with strategic partnerships. The company generates revenue through several mechanisms: Partnership Revenue represents the primary income source, typically accounting for 80-90% of total revenue. This includes upfront licensing payments, research and development funding, milestone payments triggered by clinical and regulatory achievements, and potential future royalties on commercialized products. Major partnerships include collaborations with Amgen (CX-904), Astellas (T-cell engagers), Bristol-Myers Squibb (checkpoint inhibitors), Moderna, and Regeneron. Internal Program Development focuses on wholly-owned assets like CX-2051 and CX-801, which the company plans to either advance through clinical development independently or potentially out-license at later stages for additional value capture. Several factors influence the company's financial performance and margins. Positive factors include successful clinical trial outcomes that trigger milestone payments, expansion of the partnership portfolio, advancement of internal programs to higher-value development stages, and validation of the Probody platform across multiple therapeutic modalities. The company's broad partnership base provides some revenue diversification and validation of its technology platform. Negative factors include clinical trial failures or safety issues that could terminate programs, partner decisions to discontinue collaborations (as occurred with AbbVie's CD71 program), increased R&D expenses as programs advance to later-stage trials, competitive pressure from other masked antibody technologies, and the inherent high failure rates in oncology drug development. The company's cash burn rate of approximately $80-90 million annually creates ongoing financing pressure, particularly given the long development timelines typical in biotechnology. The business model is characteristic of platform biotechnology companies, where success depends on demonstrating broad applicability of the core technology across multiple therapeutic areas and partnership opportunities.
Competitive moat
CytomX's competitive moat centers on its proprietary Probody technology platform and accumulated intellectual property, though this moat faces several limitations. The company's primary defensive position stems from its extensive patent portfolio covering the masking and conditional activation mechanisms that are core to Probody therapeutics. This intellectual property provides some protection against direct copying of the technology approach. The company has also built specialized expertise in protein engineering and conditional activation mechanisms that would be difficult for competitors to replicate quickly. CytomX's multi-year head start in developing masked therapeutics has allowed it to accumulate clinical data and regulatory experience that creates some barriers to entry. The validation of the platform across multiple therapeutic modalities (ADCs, T-cell engagers, cytokines, checkpoint inhibitors) demonstrates broad applicability and increases the difficulty for competitors to match the breadth of applications. However, the moat is relatively narrow and vulnerable to several competitive threats. Large pharmaceutical companies with substantial resources could potentially develop alternative masking technologies or acquire competing platforms. The biotechnology sector has seen numerous companies working on tumor-targeted delivery mechanisms, including other conditional activation approaches, targeted drug delivery systems, and next-generation antibody engineering platforms. The company's reliance on partnerships also creates strategic vulnerability, as partners could potentially develop competing internal capabilities or choose alternative technology platforms. Patent expiration timelines and the potential for design-around solutions further limit the durability of the intellectual property moat. Most critically, the ultimate validation of CytomX's moat depends on demonstrating superior clinical outcomes compared to existing therapies and competing approaches. Until the company achieves significant clinical successes and potential regulatory approvals, the defensive value of its technology platform remains largely theoretical. The biotechnology industry's high failure rates mean that even promising platforms can lose competitive relevance if clinical development does not deliver meaningful patient benefits.
Risks & safety
CytomX presents a moderate to high financial risk profile typical of clinical-stage biotechnology companies, with several concerning liquidity indicators offset by recent revenue growth. Overall Assessment: The company faces significant cash burn pressure with limited near-term catalysts for major financing, though recent partnership revenues have provided some stability. • Cash Burn and Solvency: Operating cash flow of -$86 million in 2024 with current cash position of $38 million creates immediate funding pressure. At current burn rates, the company has extended its cash runway to Q2 2026, but will likely require additional financing within 12-18 months. • Debt and Liabilities: Total liabilities of $121 million exceed total assets of $120 million, indicating negative book value. Current ratio of 1.25 shows modest liquidity coverage, but the company's high current liabilities relative to cash position creates near-term pressure. • Valuation Metrics: Trading at 0.59x P/E ratio and 2.21x price-to-book based on recent profitable quarters, though these metrics are distorted by partnership milestone payments rather than sustainable operating performance. EV/EBITDA of 0.17x appears attractive but reflects the volatile nature of partnership-driven revenues. • Other Considerations: Revenue volatility tied to partnership milestones creates unpredictable cash flows. The company's dependence on clinical trial outcomes for both internal programs and partnership continuation adds execution risk to the financial profile.
Recent development
Over the past few years, CytomX has undergone significant strategic evolution, transitioning from a broader pipeline approach to a more focused development strategy centered on its most promising Probody therapeutic modalities. The company has prioritized wholly-owned programs, particularly CX-2051 (EpCAM-targeted ADC) and CX-801 (masked interferon alpha), while advancing CX-904 through its Amgen partnership. CX-2051 has emerged as the lead internal program, with the company focusing specifically on colorectal cancer applications and expecting initial Phase 1a data in the first half of 2025. This represents a strategic narrowing from broader oncology applications to a more targeted indication where EPCAM expression is consistently high. Partnership strategy has evolved significantly, with some notable discontinuations and new additions. Bristol-Myers Squibb discontinued the BMS-986288 CTLA-4 program, while AbbVie decided not to advance the CD71 program (CX-2029), returning rights to CytomX. Conversely, the company has established new collaborations with Moderna and Regeneron, expanding its partnership base beyond traditional pharmaceutical companies into newer biotechnology platforms. The T-cell engager platform has shown particularly promising clinical results, with CX-904 demonstrating encouraging efficacy signals in pancreatic cancer, a notoriously difficult-to-treat indication. The confirmed partial responses, including an 83% tumor reduction in one patient, have provided validation for the Probody masking approach in reducing cytokine release syndrome while maintaining efficacy. Financial management has become more disciplined, with the company extending its cash runway to Q2 2026 through operational efficiency improvements and strategic milestone achievements. The company achieved $5 million in milestone payments from Astellas and has focused on advancing programs that can generate near-term partnership value while maintaining development momentum on wholly-owned assets. Platform expansion has continued with over 15 active discovery programs across partnerships, with the majority now focused on masked T-cell engagers, reflecting the clinical validation of this modality and market demand for improved safety profiles in T-cell engaging therapeutics.
CTMX company profile · for informational purposes only — not investment advice.
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