Dreaded 'high placebo rate' hits Immunic's psoriasis trial, causing investors to flee

With Halloween around the corner, the bogeyman of biotech—high placebo rate—has spooked investors in Immunic, sending its stock down 71% to $2.60 in premarket trading. The company blamed the response rate in the placebo arm for a disappointing interim look at blinded data from its phase 1b psoriasis trial.

Immunic randomized 41 people with moderate to severe psoriasis to take placebo or one of two doses of IMU-935, its inverse agonist of retinoic acid-related orphan receptor gamma, for 28 days. At the end of the treatment period, the biotech took a look at the mean, group-level data in a preplanned interim analysis. The glimpse at the data delivered bad news.

While Immunic saw improvements on the Psoriasis Area and Severity Index, all three arms performed comparably, suggesting that IMU-935 is no better than placebo at treating the skin condition. Immunic said the decline in the still-blinded control group was greater than expected based on other studies. 

At this stage, the biotech lacks the data to dig into the details of what happened. Notably, Immunic is yet to receive the unblinded individual patient data or any biomarker, pharmacokinetic or pharmacodynamic data. Management will decide on the development path for IMU-935 after getting a look at the data, but it remains committed to the candidate in psoriasis and other indications. 

“The unexpected high placebo rates observed in this interim analysis are disappointing and confound the evaluation of activity in the investigated active treatment arms. We have significant flexibility to explore higher dosing and longer treatment periods of this promising molecule,” Andreas Muehler, M.D., chief medical officer at Immunic, said in a release.

The setback comes months after another Immunic candidate, IMU-838, failed a phase 2 clinical trial in patients with ulcerative colitis. Immunic responded to the phase 2 flop by stopping in-house work on the indication, although it continued with a phase 3 trial of IMU-838 in multiple sclerosis.