(Bloomberg) -- Roche Holding AG’s much awaited drug for Alzheimer’s disease failed in a pair of large studies, a fresh disappointment in a research field marred with failures.

The experimental medicine, called gantenerumab, didn’t slow clinical decline in people with early Alzheimer’s, the Swiss drugmaker said Monday. Neither study met its main research objective. The stock dropped as much as 5.7%. 

Hope swelled for the Roche drug after a similar treatment hit a milestone two months ago, becoming the first product to slow progression of Alzheimer’s in a definitive trial. 

But the medicine didn’t match the success of Biogen Inc. and Eisai Co.’s lecanemab. It removed less beta amyloid protein than researchers had expected from patients’ brains. 

Both drugs are antibodies that target the protein that accumulates years before symptoms of Alzheimer’s appear, though they bind to beta amyloid in different ways. Eli Lilly & Co. also has a similar drug in development, with results expected next year.

“Gantenerumab’s failure is likely due to lower-than-expected levels of beta-amyloid removal,” Peter Welford and colleagues at Jefferies wrote in a note. 

The failures don’t come as a surprise, and many analysts hadn’t worked gantenerumab into their revenue forecasts. Those at Jefferies had estimated that the drug could generate $6 billion in annual sales in the unlikely event that it succeeded. They didn’t change their buy rating on the stock. 

Back From The Brink

Others took a more negative view. Analysts at Oddo said the announcement confirms their “underperform” rating after some pipeline setbacks in cancer. The share decline was the steepest in about six months. 

Gantenerumab’s demise is a boost for Biogen and Lilly, said Tim Anderson, an analyst at Wolfe Research. Biogen shares rose 5% in trading before US exchanges opened. Lilly gained 1.7%. Eisai jumped as much as 7.8% in Tokyo trading Tuesday. 

Roche had brought the drug back from the brink of failure once already. After it didn’t help patients more than a placebo in a study in 2014, the company ratcheted up the dose to try again. 

To show clearly whether the medicine did help patients, the Swiss drugmaker decided to run two simultaneous large studies. 

“We are committed to going after this disease,” said Rachelle Doody, global head of neurodegeneration at Roche. “And we will continue to study molecules that target amyloid in different ways to different degrees, as well as other molecular targets.”

In its pipeline, the company has a version of gantenerumab designed to better get into the brain, which would be ready for the market no sooner than 2025.

Like Biogen and Eisai, Roche didn’t release the full study results yet, making comparisons between the two trials difficult. Both companies will give details at a conference at the end of the month. 

The people who got the Roche medicine showed a rate of clinical decline that was 8% and 6% lower, in the respective trials, than those on placebo -- a result that wasn’t statistically significant. By comparison, Eisai and Biogen’s lecanemab showed a 27% reduction. 

Germany’s MorphoSys, Roche’s partner for the drug, saw shares plunge 25% in Frankfurt. 

--With assistance from Kanoko Matsuyama.

(Updates with Eisai shares in ninth paragraph)

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