8-K: Werewolf Therapeutics Announces Promising Clinical Data for WTX-124 at ASCO 2024

Werewolf Therapeutics reported encouraging preliminary clinical data from its Phase 1/1b trial of WTX-124, showing clinical activity and a favorable safety profile in patients with advanced solid tumors.

Summary

• Werewolf Therapeutics announced preliminary clinical data from its Phase 1/1b trial of WTX-124, a conditionally activated Interleukin-2 (IL-2) molecule.
• The data, presented at the 2024 ASCO Annual Meeting, included results from 47 heavily pretreated patients with advanced or metastatic solid tumors.
• 35 patients received WTX-124 monotherapy at doses ranging from 1 mg to 28 mg, while 12 patients received WTX-124 in combination with pembrolizumab at doses from 3 mg to 12 mg.
• Monotherapy with WTX-124 resulted in three objective clinical responses, including one durable confirmed complete response and two partial responses.
• Responding patients showed 100% regression of target lesions, with responses occurring within the first two cycles of therapy.
• Treatment-related adverse events were primarily mild to moderate, manageable, and reversible, with no new safety signals identified in the combination therapy.
• Analysis of tumor biopsies indicated that WTX-124 activated effector T cells preferentially over regulatory T cells.
• The company has selected 18 mg of WTX-124 administered intravenously every two weeks as the recommended dose for expansion (RDE).
• Three expansion arms have been opened in advanced or metastatic renal cell carcinoma, cutaneous melanoma, and cutaneous squamous cell carcinoma.
• Preliminary data from these expansion arms are expected in the fourth quarter of 2024 or the first quarter of 2025.
• The company is continuing dose escalation of WTX-124 in combination with pembrolizumab and expects to select an RDE for the combination in the third quarter of 2024.
• The company also plans to engage regulators to discuss potential registrational pathways for WTX-124, including strategies for monotherapy accelerated approval.

Sentiment

Score: 8

Explanation: The document presents very positive preliminary clinical data with a clear path forward for further development. The safety profile is encouraging, and the efficacy signals are strong, suggesting a promising future for the drug. The company is also actively engaging with regulators, which is a positive sign.

Positives

• WTX-124 demonstrated clinical activity in heavily pretreated patients who were refractory to standard of care therapies, including checkpoint inhibitors.
• The drug was generally well-tolerated in an outpatient setting, with manageable and reversible adverse events.
• The observed responses were rapid, occurring within the first two cycles of therapy, and durable.
• The drug showed a favorable safety profile, with no evidence of vascular leak syndrome, cytokine release syndrome, or infusion reactions.
• The combination therapy with pembrolizumab did not show an increase in the frequency or severity of adverse events compared to monotherapy.
• The company is actively pursuing regulatory pathways for accelerated approval.

Negatives

• The data is preliminary and based on a limited number of patients.
• The study population was heavily pretreated, which may not be representative of all patients.
• The long-term efficacy and safety of WTX-124 are still under evaluation.
• The company is still in the process of dose escalation for the combination therapy.

Risks

• The development of product candidates is subject to uncertainties, including the conduct of research activities and clinical trials.
• The availability and timing of results from preclinical studies and clinical trials are uncertain.
• The company's ability to obtain regulatory approval for investigational new drug applications is not guaranteed.
• Interim or preliminary data from clinical trials may not be predictive of the results of future trials.
• The company's ability to obtain sufficient cash resources to fund its operations is subject to risks and uncertainties.

Future Outlook

The company plans to continue dose escalation of WTX-124 in combination with pembrolizumab, select a recommended dose for expansion in the third quarter of 2024, and engage regulators to discuss potential registrational pathways, including strategies for monotherapy accelerated approval. Preliminary data from the expansion arms are expected in the fourth quarter of 2024 or the first quarter of 2025.

Management Comments

• Justin Moser, M.D., stated that the emerging data from the Phase 1/1b clinical trial of WTX-124 suggest that we may potentially achieve durable objective responses with a favorable safety profile for patients in the outpatient setting.
• Randi Isaacs, M.D., added that the results reinforce their conviction in WTX-124 as a potential best-in-class IL-2 therapy.

Industry Context

This announcement is significant in the context of the broader immuno-oncology field, where there is a need for more effective and less toxic therapies. The development of a conditionally activated IL-2 molecule like WTX-124 could address the limitations of conventional high-dose IL-2 therapies, which are known for their toxicity. The positive results from the combination therapy with pembrolizumab also align with the trend of combining immunotherapies to enhance efficacy.

Comparison to Industry Standards

• High-dose IL-2 (HD IL-2) therapies like aldesleukin (Proleukin) have shown efficacy in some cancers, but are limited by severe toxicity, making many patients ineligible.
• Werewolf's WTX-124 aims to improve upon HD IL-2 by selectively releasing IL-2 in the tumor microenvironment, reducing systemic toxicity.
• The reported complete response and partial responses in patients who had failed prior checkpoint inhibitor therapy are encouraging, as these patients often have limited treatment options.
• The safety profile of WTX-124, with primarily mild to moderate adverse events, is a notable improvement over the known toxicities of HD IL-2.
• Companies like Bristol Myers Squibb (Opdivo, Yervoy) and Merck (Keytruda) have established checkpoint inhibitors as a standard of care, and Werewolf's combination approach with pembrolizumab aligns with this trend.
• The use of NanoString analysis to demonstrate T-cell activation is a common biomarker approach in immuno-oncology research, and the results support the mechanism of action of WTX-124.

Stakeholder Impact

• Shareholders may view the positive clinical data as a positive sign for the company's future prospects.
• Patients with advanced solid tumors may benefit from the development of a new treatment option.
• Employees may be motivated by the progress of the clinical trial and the potential for a successful product launch.
• The company's suppliers and partners may see increased business opportunities as the program advances.

Next Steps

• The company will progress into the Phase 1b dose-expansion portion of the trial with a monotherapy dose of 18 mg.
• Three expansion arms in advanced or metastatic renal cell carcinoma, cutaneous melanoma, and cutaneous squamous cell carcinoma are now open for enrollment.
• Dose escalation will continue for WTX-124 in combination with pembrolizumab, with an expected RDE selection in the third quarter of 2024.
• The company plans to engage regulators to discuss potential registrational pathways for WTX-124.

Key Dates

Keywords

WTX-124, Interleukin-2, IL-2, Immunotherapy, Cancer, Solid Tumors, Clinical Trial, ASCO, Pembrolizumab, Checkpoint Inhibitor, Monotherapy, Combination Therapy, Dose Escalation, Complete Response, Partial Response