S-1: Crescent Biopharma Forges Oncology Partnerships, Secures Funding

Crescent Biopharma announces strategic partnerships with Kelun-Biotech and Paragon Therapeutics, securing $100 million in upfront payments and advancing its oncology pipeline with CR-001, CR-002, and SKB105 (CR-003) towards Phase 1/2 trials in 2026.

Summary

• Crescent Biopharma, a clinical-stage biotechnology company, is focused on developing transformative therapies for cancer patients, with a pipeline including a PD-1 x VEGF bispecific antibody (CR-001) and antibody-drug conjugates (ADCs) (CR-002, SKB105/CR-003).
• The company entered into a strategic partnership with Sichuan Kelun-Biotech Biopharmaceutical Co., Ltd. (Kelun) on December 2, 2025.
• Under the CR-001 License Agreement, Crescent granted Kelun exclusive rights to research, develop, manufacture, and commercialize CR-001 in Greater China (mainland China, Hong Kong, Macau, and Taiwan). Crescent retains all rights outside this territory.
• Kelun will pay Crescent an upfront payment of $20 million, up to $30 million in development milestone payments, and tiered low-to-mid single-digit royalties on net sales of CR-001 in the SKB Territory.
• Crescent may also pay Kelun $5 million if Kelun initiates a Crescent-approved combination study with CR-001 prior to December 31, 2026.
• Under the SKB105 License and Collaboration Agreement, Kelun granted Crescent exclusive rights to research, develop, manufacture, and commercialize SKB105 (to be developed as CR-003) in all territories outside Greater China.
• Crescent will pay Kelun an upfront payment of $80 million, up to $345 million in clinical and regulatory milestone payments, up to $902.5 million in sales-based milestone payments, and tiered mid-single-digit to low double-digit royalties on net sales of SKB105.
• Crescent also has existing licensing arrangements with Paragon Therapeutics, Inc. for CR-001 and CR-002, having exercised options for both and entered into related license agreements.
• The company completed a private placement on December 8, 2025, raising approximately $185 million through the sale of 13,664,251 ordinary shares and pre-funded warrants for 131,434 ordinary shares.
• As of September 30, 2025, Crescent had cash and cash equivalents of $133.3 million and an accumulated deficit of $79.4 million.
• The company incurred net losses of $24.6 million for the three months ended September 30, 2025, and $61.5 million for the nine months ended September 30, 2025.
• Research and development expenses were $20.3 million for the three months ended September 30, 2025, and $43.1 million for the nine months ended September 30, 2025.
• General and administrative expenses were $5.5 million for the three months ended September 30, 2025, and $18.1 million for the nine months ended September 30, 2025.
• Crescent expects its existing cash to fund operating plans for at least twelve months from the financial statement issuance date (January 7, 2026).
• The company is a smaller reporting company and has elected to comply with reduced public company reporting requirements.

Sentiment

Score: 7

Explanation: The filing presents a positive outlook due to significant strategic partnerships, substantial upfront payments, and a clear path for advancing multiple oncology drug candidates into clinical trials. The preclinical data for CR-001, CR-002, and CR-003 show promising differentiation and efficacy compared to industry benchmarks. However, the company's early stage, historical losses, and ongoing need for substantial future funding introduce considerable risk, balancing the overall sentiment.

Positives

• Secured significant upfront payments totaling $100 million ($20M from Kelun for CR-001 rights, $80M to Kelun for SKB105 rights).
• Established a strategic partnership with Kelun-Biotech, a leading Chinese biotech company with commercially approved ADCs, expanding Crescent's pipeline with SKB105 (CR-003).
• The collaboration with Kelun enables mutual advancement of CR-001 and CR-003 globally, leveraging China's clinical resources to expedite development and potentially limit the need for bridging studies across populations.
• CR-001 is designed to replicate the functional properties of ivonescimab, which demonstrated superior efficacy over pembrolizumab in a Phase 3 trial for NSCLC, suggesting strong potential.
• CR-002 is differentiated from other ADCs by efficient internalization, stable linker, and a topoisomerase inhibitor payload, which has shown higher antitumor activity and increased tolerability in other ADCs.
• SKB105 (CR-003) demonstrated superior cell internalization in low antigen density cancer cell lines and potent in vivo antitumor activity in preclinical models compared to a competitor ADC (SGN-B6A).
• SKB105 (CR-003) showed enhanced stability and a superior half-life in preclinical models, suggesting a differentiated safety profile.
• Anticipated initiation of four clinical trials in 2026, including monotherapy trials for CR-001, CR-002, and CR-003, and the first CR-001 ADC combination trial.
• Potential for significant future milestone payments up to $30 million for CR-001 and up to $1.25 billion for SKB105, plus tiered royalties on net sales.
• Successful private placement raising approximately $185 million, strengthening the company's capital position.

Negatives

• The company has a limited operating history, has not completed any clinical trials, and has no products approved for commercial sale.
• Historically incurred significant operating losses ($61.5 million for the nine months ended September 30, 2025) and anticipates continued losses for the foreseeable future.
• Has never generated revenue from product sales and may never be profitable.
• Will need to raise substantial additional capital to fund future operations, and such funding may not be available on acceptable terms or at all.
• Raising additional capital may cause dilution to shareholders, restrict operations, or require relinquishing rights to technologies or product candidates.
• Substantially dependent on the success of lead program CR-001 and ADC programs CR-002 and CR-003, which may not be successful.
• The approach to discovery and development, particularly for CR-001 replicating ivonescimab, is unproven in Crescent's hands, and clinical data may not be similar or comparable.
• Potential for CR-001 to be associated with adverse side effects, such as fatal pulmonary hemorrhage observed with anti-VEGF inhibitors like bevacizumab, which could limit market acceptance.
• Competition from entities with significantly greater financial resources and expertise in drug development and commercialization.
• Certain programs may compete with other internal programs, potentially impacting patient enrollment or future revenue.
• Reliance on third parties for preclinical studies, clinical trials, and manufacturing, which introduces risks of delays or failures in contractual duties.
• Reliance on third parties operating in China (e.g., WuXi Biologics, Kelun) exposes the company to additional risks, including U.S. legislation like the BIOSECURE Act, trade restrictions, and changes in Chinese regulations.
• The company does not currently solely own any issued patents or pending patent applications; its patent portfolio is in-licensed, creating dependence on licensors.
• The company does not anticipate paying any cash dividends in the foreseeable future.
• Preferred directors elected by Series A Preferred Shares holders (Fairmount affiliate) have significant voting power (60% of total board votes), potentially controlling board decisions.
• The company's ability to use Net Operating Loss (NOL) carryforwards and other tax attributes may be limited due to ownership changes.

Risks

• Inability to raise additional capital on acceptable terms, leading to delays, scaling back, or discontinuation of development/commercialization efforts.
• Failure to generate revenue from product sales and achieve profitability.
• Drug development and regulatory approval processes are costly, time-consuming, and highly uncertain.
• Substantial dependence on the success of CR-001, CR-002, and CR-003, with no assurance of successful clinical trials or regulatory approval.
• Inability to meet chemistry, manufacturing, and control (CMC) requirements for programs.
• Competition from other biopharmaceutical companies, academic institutions, and governmental agencies.
• Delays in meeting projected development goals, increasing expenses and potentially declining share price.
• Drug delivery devices used for product candidates may have their own regulatory, development, and supply risks.
• Unproven nature of the company's discovery and development approach, particularly for CR-001, with no guarantee of viable programs or similar results to ivonescimab.
• Potential for adverse side effects, adverse events, or other safety risks associated with product candidates, delaying or precluding approval.
• Inability to obtain accelerated approval, requiring additional clinical trials or increasing the size/duration of pivotal trials.
• Expenditure of limited resources on less profitable or less likely to succeed programs.
• Failure to achieve adequate market acceptance for approved products among clinicians, patients, and payors.
• Internal programs competing with each other for patient enrollment or market share.
• FDA or foreign regulatory authorities not accepting data from trials conducted outside the United States.
• Extensive ongoing regulatory obligations and review post-approval, leading to significant additional expense or penalties for non-compliance.
• Impact of current and future U.S. healthcare reform legislation or regulation on coverage, reimbursement, and pricing.
• Exposure to U.S. and foreign export/import controls, sanctions, embargoes, anti-corruption, and anti-money laundering laws.
• Disruptions at government agencies (FDA, SEC) due to funding shortages, personnel changes, or global health concerns.
• Uncertainty in obtaining and protecting patent rights, and protecting other proprietary rights, as the company does not solely own issued patents.
• Inability to obtain or maintain necessary rights to programs through acquisitions and in-licenses.
• Patent infringement claims or the need to file such claims, resulting in substantial costs and liability.
• Changes to patent laws in the United States and other jurisdictions diminishing patent value.
• Failure to identify or correctly interpret relevant third-party patents.
• Claims challenging the inventorship or ownership of patents and other intellectual property.
• Inadequate patent terms to protect the competitive position of product candidates.
• Technology licensed from Paragon and Kelun may be subject to retained rights.
• Unsuccessful collaboration arrangements with third parties, including Kelun.
• Third parties failing to properly carry out contractual duties for preclinical studies and clinical trials.
• Inability to use third-party manufacturing sites or difficulties in production, or need to switch manufacturers.
• Dependence on key personnel and difficulties in recruiting and retaining highly qualified personnel.
• Difficulties in managing organizational growth.
• Inaccurate estimates of market opportunity and forecasts of market growth.
• Significant disruptions of information technology systems or breaches of data security.
• Changes in and failures to comply with U.S. and foreign privacy and data protection laws.
• Exposure to costly and damaging liability claims, with insurance potentially not covering all damages.
• Adverse effects from macroeconomic conditions, including economic downturns, inflation, interest rate increases, natural disasters, public health crises, and geopolitical events.
• Negative impact from sustainability or environmental, social, and corporate governance (ESG) matters or reporting.
• Future sales of shares by existing shareholders causing share price decline.
• Future sales and issuances of equity and debt resulting in additional dilution.
• Limited ability to use Net Operating Loss (NOL) carryforwards and other tax attributes due to ownership changes.
• Preferred directors elected by Series A Preferred Shares holders having the ability to control or significantly influence board matters.
• Cayman Islands law and Articles of Association having anti-takeover implications, limiting shareholder ability to influence change of control.

Future Outlook

Crescent Biopharma anticipates initiating global Phase 1/2 trials for CR-001 in solid tumors and for SKB105 (CR-003) in China in Q1 2026. A Phase 1/2 trial for CR-002 is expected in H2 2026, with the first CR-001 ADC combination trial also planned for H2 2026. The company expects to share meaningful clinical data on CR-001's profile (safety, PK, preliminary anti-tumor activity) in Q1 2027, and initial data from the CR-001 and CR-003 combination trial by year-end 2027. Crescent aims to expand its pipeline through internal development, its relationship with Paragon, and external sources, focusing on best-in-class ADCs that can synergize with CR-001.

Management Comments

• Dr. Michael Ge, CEO of Kelun-Biotech: "We are pleased to have entered into a partnership with Crescent for two innovative assets, CR-001 and SKB105. This collaboration complements and strengthens our differentiated oncology pipeline by the addition of CR-001 and also enables us to advance the development of SKB105 in the global market, bolstering its potential commercial value and our global collaboration network. Our creative global partnership combines the capabilities of both companies to explore novel monotherapies and combination strategies for tumor treatments with SKB105 and CR-001. By leveraging China's abundant clinical resources and execution efficiency, we aim to expedite clinical development while rigorously maintaining the highest global standards. We believe this partnership creates a powerful synergy to maximize the potential of these two drug candidates for the treatment of patients in both China and the rest of the world."
• Joshua Brumm, CEO of Crescent: "We are thrilled to be partnering with Kelun-Biotech, an established leader in the development and commercialization of ADCs who shares our commitment to bringing next generation therapeutics that can improve outcomes for people living with cancer. This collaboration expands our pipeline with the addition of SKB105, furthers our strategy of advancing multiple modalities across our portfolio, and accelerates our efforts to deliver synergistic combinations with CR-001, which has the potential to be a foundational backbone therapy. We look forward to working with Kelun-Biotech to drive innovative therapeutics with the potential to address multiple tumor types and transform cancer care."

Industry Context

The oncology market, particularly for immune checkpoint inhibitors and ADCs, is highly competitive and rapidly evolving, with global annual sales for PD-1/PD-L1 inhibitors exceeding $50 billion. Despite their success, many patients do not respond to current checkpoint inhibitors, driving demand for novel combination therapies. Ivonescimab, a PD-1 x VEGF bispecific antibody, has shown superior efficacy to Keytruda in NSCLC, validating the mechanism of action that Crescent's CR-001 aims to replicate. The ADC market is also expanding rapidly, projected to reach over $29 billion by 2032, with topoisomerase inhibitor payloads demonstrating improved efficacy and tolerability compared to microtubule inhibitors. The strategic partnerships and focus on synergistic combinations of bispecific antibodies and ADCs align with industry trends seeking to address unmet needs in solid tumors and improve patient outcomes.

Comparison to Industry Standards

• CR-001 is designed to replicate the functional properties of ivonescimab, a PD-1 x VEGF bispecific antibody, which demonstrated superior progression-free survival (PFS) of 11.1 months compared to 5.8 months for Keytruda (pembrolizumab) in the HARMONi-2 Phase 3 trial for non-small cell lung cancer (NSCLC).
• CR-001's preclinical studies showed cooperative pharmacology with increased binding to PD-1 and signal blockade in the presence of VEGF, similar to ivonescimab.
• CR-002, an ADC with a topoisomerase payload, is differentiated from other PD-L1 directed ADCs like Pfizer's SGN-PDL1V (which uses a microtubule inhibitor payload). Topoisomerase inhibitor ADCs have shown higher overall response rates (ORR) and lower rates of peripheral neuropathy (PN) compared to microtubule inhibitor payloads in HER2 and TROP2 directed ADCs (e.g., Enhertu vs. Kadcyla, Dato-DXd vs. PF-06664178).
• CR-002 demonstrated more potent cell toxicity in vitro than DXd ADCs created using antibodies with higher affinities for PD-L1, and led to complete responses in 8 of 8 mice in a Karpas-299 Non-Hodgkins Leukemia (NHL) model, performing favorably against benchmark antibodies (opoucolimab-DXd, SG-559-01-DXd, BMS-936559-DXd).
• SKB105 (CR-003), an ITGB6-directed ADC with a topoisomerase inhibitor payload, demonstrated superior cell internalization in low antigen density cancer cell lines compared to Seagen's SGN-B6A (now Pfizer's sigvotatug vedotin).
• CR-003 showed superior antitumor responses in NCIH358 NSCLC and CFPAC-1 pancreatic CDX tumor models, leading to tumor shrinkage, whereas SGN-B6A only delayed tumor growth.
• CR-003 exhibited enhanced stability and a superior pharmacokinetic (PK) profile (superimposable ADC and total antibody curves, higher AUC) compared to SGN-B6A, suggesting lower levels of free payload in circulation and a differentiated safety profile.
• The combination of topoisomerase ADCs and immune checkpoint inhibitors has shown improvements in PFS, as seen in the ASCENT-04 trial where sacituzumab govitecan (Trodelvy) plus pembrolizumab resulted in a median PFS of 11.2 months versus 7.8 months for chemotherapy plus pembrolizumab in TNBC.

Corporate Governance

Related Party Transactions

• Fairmount Funds Management LLC (Fairmount), Paragon Therapeutics, Inc. (Paragon), and Parascent Holding LLC (Parascent) are identified as related parties.
• Fairmount, through an affiliate fund, owned approximately 74% of Crescent's outstanding stock (assuming conversion of preferred stock) as of December 31, 2024, and beneficially owns more than 5% of Crescent's voting securities as of December 31, 2025.
• Two of Crescent's directors, Peter Harwin and Jonathan Violin, are affiliated with Fairmount.
• Fairmount appointed Paragon's board of directors and has the contractual right to approve the appointment of any executive officers of Paragon.
• Parascent was formed by Paragon to hold equity in Crescent and share profits with Paragon employees.
• In September 2024, Crescent issued 20,000,000 shares of Series Seed Preferred Stock to Fairmount for $4.0 million.
• In October 2024, Fairmount, through an affiliate fund, held a Convertible Note with an initial principal amount of $15.0 million out of a total of $37.5 million issued by Crescent.
• In October 2024, Crescent issued 19,740 Restricted Stock Awards (RSAs) to a consultant (an employee of Fairmount) and 197,404 RSAs and options to purchase 763,913 shares to Crescent's CEO (also a Fairmount employee).
• Crescent recognized $13.2 million in R&D expenses and $0.1 million in G&A expenses for services from Paragon and Parascent under the Paragon Option Agreements for the period ended December 31, 2024.
• As of December 31, 2024, Crescent had $7.2 million in related party accounts payable to Paragon and Parascent.
• Crescent paid Paragon a $1.3 million research initiation fee for CR-001 in December 2024.
• Crescent paid Paragon a $1.5 million milestone payment for CR-001 development candidate in January 2025.
• Crescent paid Paragon a $2.5 million research initiation fee for CR-002 in December 2024.
• Crescent paid Paragon a $5.0 million milestone payment for CR-002 development candidate in September 2025.
• Crescent has paid Paragon $15.7 million for CR-001 development costs, $13.9 million for CR-002 development costs, and $2.2 million for Former CR-003 development costs through the effective dates of the agreements.
• Under the Paragon Option Agreements, Parascent is entitled to warrants to purchase 1.00% of Crescent's outstanding capital stock on a fully-diluted basis on December 31, 2025, and December 31, 2026.
• Jonathan Violin, a director, received $150,000 in consulting fees for services provided to the company in 2025.

Stakeholder Impact

• Shareholders: Potential for significant long-term value creation if product candidates achieve regulatory approval and commercial success, but also face substantial dilution risk from future capital raises and the concentrated voting power of Series A Preferred Shareholders.
• Employees: Continued investment in R&D and growth of the organization, with competitive compensation and benefits, but also dependence on key personnel and intense competition for talent.
• Customers (future patients): Potential for transformative therapies for cancer, addressing unmet medical needs, but also risks related to product safety, efficacy, and market acceptance.
• Partners (Kelun-Biotech, Paragon Therapeutics): Strengthened collaboration and mutual advancement of drug candidates, with potential for milestone and royalty payments, but also contractual obligations and potential disputes.
• Creditors: The company's historical losses and need for future funding present credit risk, though recent private placement provides near-term liquidity.

Next Steps

• Initiate a global Phase 1/2 trial of CR-001 in up to eight solid tumor types in Q1 2026 (ASCEND trial).
• Initiate a Phase 1/2 clinical trial of SKB105 (CR-003) in China in Q1 2026.
• File an IND for CR-002 in mid-2026.
• Initiate a Phase 1/2 trial of CR-002 in H2 2026.
• Initiate the first CR-001 ADC combination trial in H2 2026.
• Share meaningful data on CR-001's clinical profile (safety, PK, preliminary anti-tumor activity) in Q1 2027.
• Expect initial data from the CR-001 and CR-003 combination trial by year-end 2027.
• Continue to expand the product portfolio through internal development, the relationship with Paragon, and external sources.
• Negotiate and execute required legal documentation for the issuance and delivery of ordinary shares to Kelun if Crescent elects to pay the $5 million development milestone in equity.

Key Dates

Recommendation

Crescent Biopharma has made significant strides by securing substantial funding through a private placement and forging strategic partnerships with Kelun-Biotech and Paragon Therapeutics. These collaborations bring in new assets (SKB105/CR-003) and provide a clear development path for its lead candidates (CR-001, CR-002, CR-003) into Phase 1/2 clinical trials in 2026. The preclinical data for these candidates show promising differentiation and potential for improved efficacy and tolerability compared to existing therapies. However, the company is still in a very early clinical stage, has a history of significant operating losses, and will require substantial additional capital to fund its extensive development pipeline through regulatory approval and commercialization. The inherent risks of drug development, including potential clinical trial failures, regulatory hurdles, and intense competition, are high. The concentrated voting power of Series A Preferred Shareholders also presents a corporate governance consideration. Given the high-risk, high-reward nature of early-stage biotechnology, coupled with recent positive developments in funding and partnerships, a 'hold' recommendation is appropriate. Investors should monitor the progress of clinical trials and future financing activities closely, as these will be critical determinants of long-term value.

Keywords

Biotechnology, Oncology, Cancer Therapy, Bispecific Antibody, PD-1, VEGF, Antibody-Drug Conjugate, ADC, CR-001, CR-002, SKB105, CR-003, Integrin Beta-6, ITGB6, Kelun-Biotech, Paragon Therapeutics, License Agreement, Collaboration, Clinical Trials, Phase 1/2, Solid Tumors, Immuno-oncology, Drug Development, SEC Filing, S-1, Private Placement, Milestone Payments, Royalties, Biopharma, Pharmaceuticals