Allergan’s (NYSE: AGN) sizable Phase II study testing Botox as a treatment for major depression among women missed hitting statistical significance for the primary endpoint at 6 weeks of therapy but the low dose did score at a couple of other time points in the study, giving Allergan execs enough confidence to move the therapy into a major Phase III program.

Written by John Carroll (ENDpts.com)

Researchers put two doses of Botox — 30 units and 50 units — into the study, which recruited 258 patients. The 50-unit dose was a bust, but:

Said Mitchell Brin, the CSO for Botox:

The treatment (LS mean for MADRS total score compared to placebo) difference for 30 U was -4.2 at 3 weeks (p- value 0.005); -3.7 at week 6 (p-value 0.053) and -3.6 at week 9 (p-value 0.049).

I think the important thing in a Phase III environment is to increase the number of patients. You bring to bear a higher statistical power with less variability and, because the data are still very fresh we can learn more things about this treatment as we continue to explore the results.

One other big difference between Phase II and Phase III, he adds, is that they will do away with the two different site networks used to test the 30 and 50 unit doses, which was required to keep the study blinded.

Said Chief Commercial Officer Bill Meury:

 If you consider the totality of all the mid-stage data now available, it’s reasonable to believe that Phase III – with more than 1 study needed for an approval — can achieve statistical significance.

The data underscore that the treatment is active against the disease and if we can manage for placebo we have a good chance of having a successful trial.

This will be an alternative for people who can’t tolerate weight gain, sexual dysfunction or other adverse events but the benefit/risk ratio for Botox is very, very high and the unmet medical need for this group of people remains high as well, making this the kind of product that can earn hundreds of millions of dollars each year, “at baseline.”

Allergan CEO Brent Saunders has been one of the most prolific deal makers in biopharma over the past year, after its merger with Pfizer (PFE) fell through. In this case, researchers were looking to see if they could nail down solid evidence of expanding the use of its wrinkle remover for depression — which has proven to be one of the toughest targets in R&D.