20-F: NuCana Reports Increased Losses, Advances Melanoma Drug

NuCana plc reported a significant increase in net losses for 2025, reaching £29.4 million, while advancing its lead oncology candidate NUC-7738 in melanoma and evaluating future paths for NUC-3373.

Summary

• NuCana plc incurred a net loss of £29.4 million for the year ended December 31, 2025, an increase from £19.0 million in 2024, bringing the accumulated deficit to £252.3 million.
• Cash and cash equivalents stood at £24.3 million as of December 31, 2025, up from £6.7 million in 2024, with a projected runway into 2029.
• Research and development expenses decreased to £12.7 million in 2025 from £18.0 million in 2024, primarily due to reduced expenditure on NuTide:323, partially offset by increased spending on NuTide:701.
• Administrative expenses increased to £8.1 million in 2025 from £5.0 million in 2024, driven by higher share-based payment expenses and professional fees related to warrant issuance.
• NUC-7738, a novel anti-cancer agent, is in the Phase 2 part of a Phase 1/2 clinical trial (NuTide:701) for patients with advanced solid tumors, specifically in combination with pembrolizumab for PD-1 inhibitor-resistant melanoma.
• Interim data from the NuTide:701 trial in September 2024 showed 9 of 12 metastatic melanoma patients achieved disease control with NUC-7738 plus pembrolizumab, including two partial responses and one complete metabolic response.
• NUC-3373, a targeted Thymidylate Synthase inhibitor, was recently evaluated in a Phase 1b/2 modular clinical trial (NuTide:303) in combination with pembrolizumab for advanced solid tumors and docetaxel for lung cancer, showing encouraging anti-cancer activity.
• The NuTide:323 randomized Phase 2 trial for NUC-3373 in metastatic colorectal cancer was discontinued in August 2024 following a futility analysis, as it was unlikely to achieve its primary objective of superior progression-free survival.
• The Acelarin Phase 3 clinical trial (NuTide:121) for biliary tract cancer was discontinued in March 2022 due to a futility analysis, despite a higher objective response rate, as it did not translate into an overall survival benefit.
• The company completed a registered direct offering and utilized an ATM sales agreement in 2025, raising gross proceeds of £19.5 million from ADS sales and £4.4 million from warrant exercises.
• A revaluation loss of £12.6 million from derivative financial instruments (warrants) was recognized in 2025.
• The company effected two ADS-to-ordinary share ratio changes in 2024 and 2025 to regain compliance with Nasdaq's minimum bid price requirement.

Sentiment

Score: 3

Explanation: StockSavvy.ai views this filing with caution. While NUC-7738 shows promising early clinical data, the significant increase in net losses and the discontinuation of two clinical trials for other candidates raise concerns about the company's development pipeline and financial sustainability, despite a longer cash runway.

Positives

• NUC-7738 in combination with pembrolizumab demonstrated encouraging efficacy signals in metastatic melanoma patients, including tumor volume reductions, prolonged time on treatment, and one complete metabolic response.
• NUC-7738 showed potential to potentiate immunotherapy by reducing PD-1 expression and increasing CD8+ T-cells in patient tumor biopsies.
• NUC-3373 exhibited significant tumor volume reductions and prolonged progression-free survival in patients with urothelial bladder cancer and metastatic melanoma in the NuTide:303 trial, indicating anti-tumor immune response potentiation.
• The company maintains a cash and cash equivalents balance of £24.3 million as of December 31, 2025, providing a projected funding runway into 2029.
• NuCana's proprietary ProTide technology is well-validated, having led to successful antiviral drugs by Gilead, and is being applied to overcome limitations of conventional nucleoside analogs in oncology.
• The company has a robust intellectual property portfolio with 284 granted patents (26 U.S. issued) and 61 pending applications, protecting its lead candidates and technology.

Negatives

• Net losses significantly increased to £29.4 million in 2025 from £19.0 million in 2024, contributing to an accumulated deficit of £252.3 million.
• The NuTide:323 randomized Phase 2 clinical trial for NUC-3373 in metastatic colorectal cancer was discontinued due to futility, as it was unlikely to achieve its primary objective.
• The Phase 3 clinical trial (NuTide:121) for Acelarin in biliary tract cancer was discontinued due to a futility analysis, despite a higher objective response rate, as it did not translate into an overall survival benefit.
• A significant non-cash revaluation loss of £12.6 million from derivative financial instruments (warrants) was recognized in 2025.
• Research and development tax credits decreased from £3.5 million in 2024 to £1.2 million in 2025, primarily due to lower eligible R&D expenses.
• The company has had to effect two ADS-to-ordinary share ratio changes (in 2024 and 2025) to maintain compliance with Nasdaq's minimum bid price requirement, indicating sustained low share price performance.

Risks

• Significant operating losses are expected to continue for the foreseeable future, and profitability may never be achieved or maintained.
• Heavy dependence on the success of NUC-7738 and NUC-3373, with no assurance of regulatory approval for any indication.
• Drug development is a lengthy, expensive, and uncertain process, with a high failure rate, especially for early-stage clinical programs.
• Limited resources and access to capital necessitate prioritization of certain ProTide candidates and indications, which may prove to be suboptimal decisions.
• Product candidates may cause undesirable side effects that could delay or prevent marketing approval, limit commercial profile, or result in negative consequences post-approval.
• Reliance on third parties for clinical trials and manufacturing increases risks of delays, non-compliance, or insufficient supply.
• Failure to obtain and maintain intellectual property protection, or infringement of others' patent rights, could impair commercialization efforts.
• Exchange rate fluctuations, particularly between the pound sterling and the U.S. dollar, may adversely affect results of operations and financial condition.
• Inadequate funding for regulatory agencies (e.g., FDA, SEC) could hinder timely review and approval processes.
• Unstable market and economic conditions, including inflation and adverse developments in the financial services industry, could negatively impact business and stock price.
• Cybersecurity incidents or failures of internal computer systems could disrupt product development programs and lead to liability.
• The price of ADSs may be volatile and could fall below Nasdaq's minimum bid price, leading to delisting.
• Potential for being classified as a Passive Foreign Investment Company (PFIC) for U.S. federal income tax purposes, resulting in adverse tax consequences for U.S. investors.

Future Outlook

NuCana anticipates seeking regulatory guidance from the FDA in 2026 regarding the potential registrational pathway for NUC-7738 in melanoma. The company also expects to report final data from the NUC-7738 Phase 2 expansion study in 2026 and announce its development plan for NUC-3373 in 2026, evaluating optimal combinations and indications for potential further clinical trials. The company believes its existing cash and cash equivalents will be sufficient to fund anticipated operations into 2029.

Management Comments

• Hugh S. Griffith, Chief Executive Officer, is a named inventor on over 398 patents and over 300 pending patent applications.
• Jeffrey Bloss, M.D., Chief Medical Officer, brings over 20 years of leadership experience in oncology at multiple pharmaceutical/biopharmaceutical companies.
• David Harrison, M.D., Head of Translational Medicine, is also a professor of Pathology at the University of St. Andrews and oversees ethics relating to human tissue at Lothian NHS University Hospitals.
• Ian Webster, Interim Chief Financial Officer, has over 20 years of experience in finance, including over 10 years in senior positions within the biopharmaceutical sector.
• Theresa Bruce, Chief Operating Officer, has over 25 years of experience in oncology research and development, leading teams in clinical planning and delivery.

Industry Context

StockSavvy.ai notes that NuCana operates in the highly competitive oncology biopharmaceutical sector, focusing on transforming nucleoside analogs, a cornerstone of chemotherapy, into more effective and safer medicines using its ProTide technology. This approach has been validated by the success of Gilead's antiviral drugs like sofosbuvir and tenofovir alafenamide fumarate, which also utilize phosphoramidate chemistry. The global chemotherapy market is projected to reach approximately $106 billion by 2030, indicating a substantial market opportunity for improved chemotherapeutic agents. The company's strategy to develop rational combination partners, particularly with immune checkpoint inhibitors, aligns with current trends in cancer therapy seeking synergistic effects to overcome resistance.

Comparison to Industry Standards

• NUC-3373, derived from 5-fluorouracil (5-FU), aims to overcome limitations of 5-FU, which is one of the most widely used chemotherapeutic agents globally and is on the WHO's List of Essential Medicines. Preclinical studies showed NUC-3373 had up to 330 times greater anti-cancer activity than 5-FU in various tumor cell lines.
• NUC-3373 generated intracellular levels of the active anti-cancer metabolite, FUDR-MP, 366 times higher than 5-FU in preclinical colorectal cancer cells, suggesting improved efficacy.
• NUC-3373 demonstrated a favorable safety profile with no hand-foot syndrome observed (a common debilitating side effect of 5-FU) and no neutropenia or Grade 3/4 mucositis or diarrhea adverse events (associated with 5-FU's toxic metabolite FUTP).
• NUC-3373's plasma half-life of 6 to 14 hours enables a shorter infusion time (30 minutes to four hours) compared to 5-FU's 46-hour continuous infusion, offering a significant administration advantage.
• NUC-7738, a transformation of 3-deoxyadenosine (3-dA), addresses 3-dA's rapid breakdown by ADA, a key limiting factor that prevented 3-dA's successful clinical development as a chemotherapy.

Management Changes

Corporate Governance

Legal Proceedings

• No pending litigation that, separately or in the aggregate, would have a material adverse effect on results of operations, financial condition, or cash flows.

Related Party Transactions

• Service agreements have been entered into with each executive officer (Hugh Griffith, David Harrison, Ian Webster, Jeffrey Bloss, Theresa Bruce).
• Deeds of indemnity have been entered into with each director and executive officer.
• The company has a related person transaction policy requiring audit committee approval for all related person transactions.

Stakeholder Impact

• Shareholders: Potential for significant dilution from future equity offerings and warrant exercises; continued volatility in ADS price due to financial performance and clinical trial outcomes; potential for delisting from Nasdaq if minimum bid price requirements are not met.
• Employees: Participation in share option schemes provides incentives, but trial discontinuations and financial losses could impact morale and retention; management changes affect leadership structure.
• Patients: Development of NUC-7738 and NUC-3373 offers potential new treatment options for various cancers, but trial discontinuations for Acelarin and NuTide:323 represent setbacks in bringing new therapies to market.
• Creditors: Recurring losses and accumulated deficit indicate ongoing financial risk, though current cash runway extends into 2029.
• Suppliers/CROs: Reliance on third-party manufacturers and CROs for clinical trials and manufacturing, with potential for disruptions or increased costs.

Next Steps

• Report final data from the NUC-7738 Phase 2 expansion study in 2026.
• Seek regulatory guidance from the FDA in 2026 regarding the potential registrational pathway for NUC-7738 in melanoma.
• Announce the development plan for NUC-3373 in 2026, evaluating optimal combinations and indications for further clinical trials.
• Continue to leverage proprietary ProTide technology platform to develop additional product candidates.
• Further expand and enhance the intellectual property position.
• Build a focused commercial organization to commercialize approved product candidates in major markets like the United States and Europe.

Key Dates

Recommendation

NuCana plc presents a mixed picture. While the significant net losses and the discontinuation of two clinical trials are concerning, the promising early-stage clinical data for NUC-7738 in melanoma, coupled with a cash runway extending into 2029, suggest that the company has the potential to advance its lead candidate. The ProTide technology is innovative and has shown promise in preclinical and early clinical settings. However, the high-risk nature of drug development, particularly in oncology, and the company's history of trial discontinuations warrant a cautious approach. Investors should hold to monitor the upcoming NUC-7738 Phase 2 expansion data and regulatory guidance, as these will be critical determinants of future value, while acknowledging the substantial financial risks and the need for successful commercialization to achieve profitability.

Keywords

NuCana, ProTides, NUC-7738, NUC-3373, Melanoma, Oncology, Clinical Trials, Biopharmaceutical, Cancer Treatment, Drug Development, SEC Filing, Nasdaq, Share Options, Financial Results, PD-1 Inhibitor, Pembrolizumab, Thymidylate Synthase, 5-Fluorouracil, Metastatic Colorectal Cancer, Biliary Tract Cancer, Gemcitabine, Phosphoramidate Chemistry, Regulatory Approval, Intellectual Property