SAN DIEGO, USA, April 16, 2026

Janux Therapeutics, Inc. has announced a key clinical milestone with the first participant dosed in its Phase 1 clinical trial of JANX014, an investigational tumor-activated T cell engager (TCE) targeting metastatic castration-resistant prostate cancer (mCRPC). This advancement marks an important step in expanding the company’s PSMA-targeted immunotherapy portfolio, reinforcing its strategy to develop next-generation cancer therapies designed to selectively activate the immune system within the tumor microenvironment. The study represents a first-in-human, open-label, multicenter trial aimed at evaluating safety, tolerability, pharmacokinetics, pharmacodynamics, and preliminary efficacy of JANX014 in patients with advanced prostate cancer.

Phase 1 Study Expands PSMA Immunotherapy Pipeline

The JANX014 program builds on Janux’s proprietary tumor-activated technology platform, which is designed to minimize systemic toxicity while maximizing anti-tumor immune response. JANX014 is a double-masked PSMA-directed T cell engager, engineered to remain inactive in circulation and become activated specifically within the tumor environment, thereby improving safety margins and therapeutic precision.

This innovative approach addresses one of the major challenges in immunotherapy—reducing off-target effects while maintaining strong efficacy. The trial will enroll adult patients with mCRPC, a late-stage form of prostate cancer with limited treatment options and high unmet medical need. By focusing on early clinical evaluation, the study aims to generate critical data that will inform dose optimization and future development strategies.

Strategic Portfolio Development in Prostate Cancer

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Janux is actively building a comprehensive prostate cancer treatment portfolio, with JANX007 as its lead clinical candidate, supported by promising early data indicating a favorable safety profile and strong clinical activity. The development of JANX014 represents an exploratory extension of this strategy, leveraging insights from ongoing programs such as JANX007 and JANX008.

The company is also advancing JANX013, a PSMA-targeted CD28 co-stimulatory program, expected to enter clinical trials in the second half of 2026. Together, these programs reflect a multi-faceted approach to targeting prostate cancer, combining different mechanisms of immune activation to address various stages of disease and patient populations. This diversified pipeline positions Janux to explore both monotherapy and combination treatment strategies, potentially enhancing clinical outcomes in challenging oncology settings.

Innovative Tumor-Activated Technology Drives Next-Gen Therapies

Janux’s proprietary platforms, including TRACTr (Tumor Activated T Cell Engager), TRACIr (Tumor Activated Immunomodulator), and ARM (Adaptive Immune Response Modulator), are designed to improve the precision and effectiveness of immunotherapies. These technologies enable the company to evaluate multiple molecular designs targeting validated cancer antigens such as PSMA, which is highly expressed in prostate cancer cells.

By using masking strategies and selective activation mechanisms, Janux aims to overcome limitations of conventional immunotherapies, such as cytokine release syndrome and systemic toxicity. The progression of JANX014 into clinical trials highlights the company’s commitment to innovative drug development and translational research, with the goal of delivering safer and more effective cancer treatments.

As the Phase 1 trial advances, Janux Therapeutics is expected to generate valuable clinical insights that could shape the future of tumor-activated immunotherapy. With a robust pipeline and a strong scientific foundation, the company is well-positioned to play a significant role in the evolving landscape of precision oncology, addressing critical gaps in treatment for patients with advanced prostate cancer.

Source: Janux Therapeutics press release