A CEO sent his stock surging 15% when he likened his new depression drug to an antibiotic — but a consultant to the company told us it won’t work that way (SAGE)

Investors’ excitement about a promising new drug for depression reached a fever pitch last week when the CEO of the company behind it likened the drug to an antibiotic.

This drug has the “potential for patients with major depressive disorder to feel well within days, with just a two week course of treatment — similar to how antibiotics are used today — instead of enduring long-term chronic treatment,” Sage Therapeutics’ CEO Jeff Jonas said on Tuesday of his company’s drug, SAGE-217.

The comments came shortly after the company said it had received the green light from the Food and Drug Administration to accelerate the approval process for its drug.

A once-only course of treatment is essentially unheard of for depression or for any other chronic disease. And experts within and outside of the company say they doubt that’s how SAGE-217 would actually work. Instead of working as a once-only treatment, they said that data on the drug suggest that its effects would likely last as long as one month. Patients would still need to take the drug regularly for long-lasting results.

More importantly, although the drug has shown a promising potential ability to treat depression in preliminary studies, those findings have yet to be borne out by the kinds of longer and larger trials that are needed before it gets anywhere near federal approval.

An area in desperate need of new treatments

Depression is the leading cause of disability worldwide, and it can kill. While not the sole cause of suicide, depression is often a contributing factor. And while suicide rates have climbed for nearly 20 years, not a single new drug for depression has emerged.

Most treatments for depression and suicidal thinking are limited to a narrow class of drugs known as selective serotonin reuptake inhibitors, or SSRIs, which includes popular drugs like Prozac and Lexapro. While they can help some people, failure rates hover around 50%.

So researchers are on the hunt for better options— options that could soon include Sage’s new compound, which preliminary studies have suggested works well to treat depressive symptoms within a short time period.

Sage’s drug would not be a one-and-done treatment

But Sage’s drug wouldn’t be a one-and-done kind of depression treatment, according to researchers within and outside the company. In sharp contrast to what Sage CEO Jeff Jonas suggested last week, the drug would most likely need to be administered regularly, possibly as frequently as every month, Gerard Sanacora, the director of the Yale Depression Research Program and a clinical advisor to Sage, told Business Insider.

“There will need to be further studies” to help the team fully understand how well SAGE-217 works and how long its depression-relieving effects last, Sanacora said.

In a statement emailed to Business Insider, a representative from Sage said:

“An important aspect of what we are doing is minimizing chronic exposure to pharmaceutical treatments for diseases like depression, a desired outcome for patients. Given the ongoing concern about chronic dosing of antidepressants, the fact that episodic dosing has not been achieved previously is precisely the reason to keep trying.”

“As noted in our recent announcement, Sage will conduct an additional open-label study of SAGE-217 that follows approximately 300 patients for 6 months and 100 patients for one year, allowing us to evaluate the potential of treating recurrent or new major depressive episodes as needed. As part of this study, patients will be retreated if symptoms of major depressive disorder return.”

Cristina Cusin, a psychiatrist at Massachusetts General Hospital and an assistant professor at Harvard University who specializes in depression, cautioned that she’s seen many promising drug candidates for depression fail once they get to the last phase of clinical study — phase 3. Sage has yet to complete those studies.

While the Sage compound appears “incredible” in some ways, Cusin said “the problem is we have seen this before with other phase 2 studies that don’t get held out in phase 3.”

So Cusin said she is “cautiously — or preliminarily — excited,” but added that she felt it was “a little excessive to say a chronic disease would disappear after two weeks, that’s something you can’t say about diabetes or any other chronic disease.”