Janux Therapeutics Announces First Participant Dosed in Phase 1 Study of JANX014

On April 16, 2026 Janux Therapeutics, Inc. (Nasdaq: JANX) (Janux), a clinical-stage biopharmaceutical company developing a broad pipeline of novel immunotherapies, reported that the first patient has been dosed in a Phase 1 clinical trial of JANX014 in patients with metastatic castration-resistant prostate cancer (mCRPC). JANX014 is a double-masked, prostate-specific membrane antigen (PSMA) directed T cell engager (TCE) designed to leverage Janux’s tumor-activated technology platform to selectively activate T cells in the tumor microenvironment.

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Janux is building a portfolio of tumor-activated PSMA therapies designed to address multiple treatment settings and mechanisms of immune engagement. Early clinical data from JANX007 have demonstrated what Janux believes is potentially a best-in-class clinical profile in mCRPC, including a favorable safety profile with no Grade 3 cytokine release syndrome observed at clinically relevant dose levels using the current CRS mitigation strategy. These data continue to guide Janux’s development strategy in prostate cancer. JANX014 represents an exploratory extension of the strategy, emerging from platform work initiated in early 2024 evaluating multiple PSMA-directed approaches. JANX014 will also explore potential future use cases where enhanced safety margins and ease of administration may be particularly important.

"We are pleased to have initiated clinical evaluation of JANX014," said David Campbell, Ph.D., President and Chief Executive Officer of Janux Therapeutics. "JANX007 remains our lead prostate program, and we believe it has established a strong clinical foundation for PSMA-directed TRACTr therapy. Insights from programs such as JANX007 and JANX008 have informed our continued platform development. We are building a prostate cancer portfolio designed to address patients across multiple stages of disease, including both single and combination approaches. Advancing programs such as JANX014 reflects our strategy of expanding on that foundation while maintaining disciplined execution on our lead program."

William Go, M.D., Ph.D., Chief Medical Officer of Janux Therapeutics, added, "Janux’s tumor-activated technology allows us to evaluate multiple molecular designs against the same validated target. As we advance JANX007, we are also developing complementary approaches within our platforms, including JANX013, our CD28 co-stimulatory PSMA-TRACIr program, along with exploratory approaches like JANX014. This innovative work is intended to help us understand how different mechanisms and masking strategies may translate into clinical benefit across patient populations in prostate cancer."

The Phase 1 study is a first-in-human, open-label, multicenter study to assess the safety, tolerability, pharmacokinetics, pharmacodynamics, and preliminary efficacy of JANX014 in adults with mCRPC.

Additional information about the study will be available at clinicaltrials.gov.

(Press release, Janux Therapeutics, APR 16, 2026, View Source [SID1234664452])