8-K: Instil Bio Partner Reports Positive Preliminary Phase 2 Data for NSCLC Drug IMM2510

Instil Bio's partner, ImmuneOnco, announced promising preliminary safety and efficacy results from its Phase 2 study of IMM2510/AXN-2510 in combination with chemotherapy for first-line advanced non-small cell lung cancer.

Summary

• ImmuneOnco Biopharmaceuticals (Shanghai) Inc. reported preliminary safety and efficacy data for IMM2510/AXN-2510 (2510) in combination with chemotherapy for first-line advanced non-small cell lung cancer (NSCLC) patients.
• As of July 1, 2025, 33 patients were dosed at 10 mg/kg of 2510.
• 21 patients had at least one tumor assessment and were considered efficacy evaluable.
• A partial response rate of 62% was observed in efficacy evaluable patients.
• Among squamous NSCLC patients, 80% (8/10) achieved partial responses.
• Among non-squamous NSCLC patients, 46% (5/11) achieved partial responses.
• The majority of efficacy evaluable patients had only one tumor assessment at the data cut-off.
• No dose-limiting toxicities were observed in the 33 safety evaluable patients.
• No treatment-related adverse events (TRAE) led to dose reduction or death.
• Only one TRAE led to drug discontinuation.
• The most common Grade 3+ TRAEs were hematologic, with uncommon clinical sequelae.
• Adverse events typically associated with VEGF inhibition (e.g., hypertension, proteinuria, hemoptysis) and immune-related adverse events were uncommon and generally low-grade.
• Infusion-related reactions were nearly all low-grade.

Sentiment

Score: 8

Explanation: The sentiment is highly positive due to strong preliminary efficacy data (high partial response rates, especially in squamous NSCLC) combined with a favorable safety profile (no DLTs, minimal severe TRAEs). While the data is preliminary, the initial results are very promising for a challenging disease area.

Positives

• High partial response rate of 62% in efficacy evaluable patients, indicating significant tumor shrinkage.
• Particularly strong partial response rate of 80% in squamous NSCLC patients.
• Favorable safety profile with no dose-limiting toxicities observed.
• Absence of treatment-related adverse events leading to dose reduction or death.
• Only one instance of a treatment-related adverse event leading to drug discontinuation.
• Common Grade 3+ TRAEs (hematologic) had uncommon clinical sequelae, suggesting manageability.
• Low incidence and generally low-grade nature of VEGF inhibition-associated and immune-related adverse events.
• Infusion-related reactions were predominantly low-grade.

Negatives

• The majority of efficacy evaluable patients had only one tumor assessment at data cut-off, meaning the data is still very preliminary and may evolve with more assessments.
• The partial response rate for non-squamous NSCLC (46%) was notably lower than for squamous NSCLC (80%).

Risks

• Preliminary nature of the data: The results are based on a limited number of patients and follow-up, and may change as more data becomes available or with longer observation periods.
• Clinical trial risks: Future results from the ongoing Phase 2 trial or subsequent trials may not replicate these preliminary findings, or the drug may not demonstrate sufficient efficacy or safety for regulatory approval.
• Regulatory approval risk: There is no guarantee that the drug will receive regulatory approval even if trials are successful.
• Market competition: The NSCLC treatment landscape is competitive, and other therapies may emerge or prove more effective.

Future Outlook

ImmuneOnco expects to present the safety and efficacy data from the Phase 2 Chemo Combo Trial at a future medical conference, indicating further updates are anticipated.

Industry Context

The announcement pertains to a potential new treatment for advanced non-small cell lung cancer (NSCLC), a leading cause of cancer-related deaths globally. The combination of a novel agent like IMM2510/AXN-2510 with chemotherapy represents a common strategy to improve outcomes in this challenging disease. The preliminary efficacy, particularly the 62% partial response rate, is notable in a first-line advanced NSCLC setting, where standard chemotherapy regimens often yield lower response rates, and combination therapies are continuously being explored to enhance patient benefit and overcome resistance mechanisms. The safety profile appears manageable, which is crucial for combination therapies.

Comparison to Industry Standards

• The 62% overall partial response rate observed in this preliminary Phase 2 data for first-line advanced NSCLC in combination with chemotherapy is highly encouraging. For comparison, historical response rates for chemotherapy alone in advanced NSCLC typically range from 25-35%.
• When compared to modern immunotherapy-chemotherapy combinations, which have become standard of care, response rates can vary. For instance, Keytruda (pembrolizumab) plus chemotherapy in KEYNOTE-189 (non-squamous NSCLC) showed an overall response rate of 48.3%, and in KEYNOTE-407 (squamous NSCLC) it was 58.4%. The 80% partial response rate in squamous NSCLC patients with IMM2510/AXN-2510 is particularly impressive relative to these benchmarks.
• The safety profile, with no dose-limiting toxicities and minimal severe TRAEs, appears favorable, especially considering the known side effects of chemotherapy and potential additional toxicities from novel agents. This suggests a potentially well-tolerated regimen compared to some existing multi-drug combinations that may have higher rates of severe adverse events.

Stakeholder Impact

• Shareholders: Positive preliminary clinical data for a key pipeline asset could lead to increased investor confidence and potential share price appreciation for Instil Bio.
• Patients: The promising efficacy and safety profile of IMM2510/AXN-2510 could offer a new, effective, and well-tolerated treatment option for patients with advanced non-small cell lung cancer, particularly those with squamous histology.
• Medical Community: The data suggests a potentially significant advancement in NSCLC treatment, warranting further attention and discussion at medical conferences.

Next Steps

• ImmuneOnco expects to present the full safety and efficacy data from the Phase 2 Chemo Combo Trial at a future medical conference.

Key Dates

Recommendation

The preliminary Phase 2 data for IMM2510/AXN-2510 in NSCLC is exceptionally strong, particularly the high partial response rates and favorable safety profile. While early-stage, these results suggest significant therapeutic potential in a large and critical oncology market. Such positive clinical milestones in biotech often lead to substantial re-rating of the stock. Investors should consider a 'strong buy' given the de-risking implied by these promising preliminary results and the potential for future value creation as the program advances.

Keywords

Non-small cell lung cancer, NSCLC, IMM2510, AXN-2510, ImmuneOnco, Instil Bio, Phase 2 trial, Clinical data, Oncology, Biopharmaceuticals, Chemotherapy combination, VEGF inhibition, Immunotherapy