After a disappointing phase 1 showing, Janux Therapeutics is kicking one of its bispecific T-cell engagers (TCEs) to the curb.
The “overall magnitude and consistency of activity” of JANX008 was subpar in its metastatic solid tumor trial, Janux disclosed in an April 27 release. As a result, the company is halting all clinical development of the molecule.
JANX008 is a masked TCE designed to bind to epidermal growth factor receptor (EGFR) on cancer cells and CD3 on T cells. Meant to only activate once inside of a tumor, JANX008 was intended to entice the immune cells to attack and kill the patient’s cancer.
The trial “enabled a rigorous evaluation of activity” of JANX008 that will help Janux advance similar molecules that remain in its pipeline, Chief Medical Officer William Go, M.D., Ph.D., said in the release.
“We observed objective responses and disease control across treated patients,” Go added. “These findings provide important insight into how target biology and masking strategy define the therapeutic window and inform the continued advancement of our pipeline.”
JANX008 was built using the same platform as Janux’s lead candidate, JANX007, which is currently in a phase 1 trial for patients with metastatic castration-resistant prostate cancer. JANX007, which targets prostate-specific membrane antigen (PSMA) and CD3, has been hailed by analysts as having best-in-class potential, despite a lackluster investor response to new data shared last December.
In an April 28 note, William Blair analysts said Janux’s management had explained that the decision to discontinue JANX008 was made “following dose expansion efficacy that did not meet the company’s internal threshold for continued development, particularly in the context of prioritizing resources toward JANX007and other PSMA-targeted programs.”
“We continue to believe the greatest focus for Janux is on the next clinical update for JANX007 from dose expansion cohorts, which we believe is most likely to come at a medical conference in early 2027 (or a corporate update in 2026 as long as this does not preclude presentation at a medical conference) to improve investor sentiment and drive upside to shares from current lows,” the analysts added.
Janux’s other clinical asset is JANX011, in early development for autoimmune diseases, while the San Diego biotech’s other wholly owned candidate is a preclinical bispecific that also targets PSMA but binds to CD28 on the T-cell side rather than CD3. Janux hopes to use this molecule, called JANX013, in combination with JANX007.
Janux’s tumor-activated platforms have also attracted the attention of Big Pharma. The company recently signed a deal to develop a preclinical candidate targeting solid tumors for Bristol Myers Squibb, netting $50 million in the near term.
The biotech also has a long-standing deal with Merck & Co., with a total potential value north of $1 billion.