Janux Therapeutics made a splash earlier this year when it debuted interim phase 1 data for T-cell engager JANX007 in prostate cancer, prompting analysts to forecast blockbuster potential for the candidate. Now, the company is continuing to ride the wave with an updated early data set that wowed analysts—and shareholders—once again.
The latest interim data showed that all of the 16 patients with heavily pretreated advanced or metastatic prostate cancer (mCRPC) who received doses of JANX007 ranging from 2 mg to 9 mg achieved noteworthy prostate-specific antigen (PSA) declines as of Nov. 15, according to Janux's Monday press release.
The reductions occurred across all dose strengths, with all 16 patients achieving a 50% decline in PSA, 10 patients (63%) seeing a 90% decline and five patients (31%) achieving a 99% decline, according to Janux.
The company touted the durability of the PSA reductions: three-quarters of patients who achieved 50% declines in PSA had their reductions last 12 weeks or more. Half of patients who met the 90% PSA decline threshold had their reductions last the same amount of time.
The “deep and durable” responses were found regardless of certain cancer characteristics such as prior treatment with a taxane therapy or an androgen receptor pathway inhibitor, Janux noted in its release.
The data show “sustainable activity” in patients who had a median of four prior treatment lines and provide “compelling support” for the doses the company has selected for phase 1b testing, CEO David Campbell, Ph.D., said in the release.
“We look forward to rapidly advancing JANX007 into second and third-line therapy where a substantial unmet need remains and where we believe JANX007’s highly differentiated profile could allow for broad usage if approved,” Campbell said. “This is an exciting day for Janux, but more importantly the prostate cancer patients we serve.”
Analysts shared in the excitement, with Evercore ISI’s Jonathon Miller describing the candidate as “firmly best-in-class” in the late-line setting. The data “somehow got even better,” Miller wrote in a Monday note to clients. In February, the analyst hailed the company's initial dataset as the “best early data I’ve seen” in mCRPC.
The company's last reported data in February showed 57% of patients meeting the PSA decline threshold of 50%, with a high-dose cohort performing even better. The result put JANX007 at the top of the pack compared to other recent late-line mCRPC studies, according to the Evercore ISI analyst, and sent shares soaring by 137%.
On Tuesday, Janux's shares jumped 60% on the heels of the updated data drop.