Updated from 6:38 am ET with additional information.

TEL AVIV (TheStreet) -- Treatment with an experimental formulation of vitamin B6 known as MDX failed to improve the symptoms of attention-deficit hyperactivity disorder compared to placebo, according to phase III study results announced by the developer of the drug, Alcobra (ADHD) , in a statement issued Monday.

However, when Alcobra removed four placebo patients from the analysis because of "extreme" responses, the MDX benefit in the adult ADHD was positive and statistically significant, the company said.

Investors weren't buying the spin. Alcobra shares are down 47% to $7.47 in Monday trading. What's wrong with just excluding some patients and claiming victory? Think about it this way: If baseball statisticians ignored all of Derek Jeter's outs, he batted 1.000 during his major league career. Alcobra is doing the same thing with the MDX study analysis and it doesn't smell right, either.

The study enrolled 300 patients with adult ADHD and randomized them to treatment with MDX or a placebo for six weeks. The primary endpoint was the change from baseline in the CAARS-INV, a widely accepted clinical measure of the presence and severity of ADHD symptoms, used in past to win approval of ADHD drugs.

Alcobra did not provide details about the primary analysis of the intent-to-treat patient population, except to say there was a non-statistically-significant trend favoring MDX over placebo when assessed by the CAARS-INV scale. The company did not break out results according to the two major subtypes of ADHD -- primary inattentive type and combined type.

In the modified intent-to-treat patients population, which omitted four placebo patients, those treated with MDX demonstrated an 11.6-point change on the CAARS-INV scale over six weeks compared to an 8.7-point change for placebo patients. Alcobra said this difference was statistically significant. Alcobra said patients with the primary inattentive and combined type of ADHD benefited similarly to MDX.

Not everyone is down on Alcobra Monday. Piper Jaffray analyst Charles Duncan believes the MDX data are encouraging and justify Alcobra moving ahead with another phase III study. Alcobra will require additional money for the next MDX study, which is the real reason why Duncan reiterated his overweight rating and $42 price target on the company. 

Alcobra's press release on the MDX study results can be found here.

Adam Feuerstein writes regularly for TheStreet. In keeping with company editorial policy, he doesn't own or short individual stocks, although he owns stock in TheStreet. He also doesn't invest in hedge funds or other private investment partnerships. Feuerstein appreciates your feedback;

click here

to send him an email.