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DBL%20Hendrix%20small.png College chemistry, 1983

Derek Lowe The 2002 Model

Dbl%20new%20portrait%20B%26W.png After 10 years of blogging. . .

Derek Lowe, an Arkansan by birth, got his BA from Hendrix College and his PhD in organic chemistry from Duke before spending time in Germany on a Humboldt Fellowship on his post-doc. He's worked for several major pharmaceutical companies since 1989 on drug discovery projects against schizophrenia, Alzheimer's, diabetes, osteoporosis and other diseases. To contact Derek email him directly: Twitter: Dereklowe

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December 5, 2011

Rexahn Rides Again

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Posted by Derek

You may remember Rexahn Pharmaceuticals being mentioned here in 2010. They're the company whose lead antidepressant drug Serdaxin showed no significance versus placebo in Phase IIa trials, and whose CEO (Dr. Ahn himself) then calmed the investment community by saying that the trial was never designed to show any statistical significance, anyway, and was therefore a success. You know, because it showed that patients could benefit from the drug, even though it didn't show that patients could benefit from the drug. You may think I'm exaggerating, but go back and read Ahn's statement and see if you still think that.

And when you do, you'll discover that Serdaxin is nothing else than clavulinic acid, the beta-lactamase inhibitor, and not the first thing you'd think of as a CNS agent. But Rexahn has pushed on to Phase IIb with it, and this time they seem to actually have been going all the way, looking for a statistically meaningful effect and everything. That hasn't gone so well, although the press release does what it can:

The randomized, double-blind, placebo-controlled study compared two doses of Serdaxin, 0.5 mg and 5 mg, to placebo over an 8-week treatment period. Results from the study did not demonstrate Serdaxin’s efficacy compared to placebo measured by the Montgomery-Asberg Depression Rating Scale (MADRS). All groups showed an approximate -14 point improvement in the protocol defined primary endpoint of MADRS. All groups had a substantial number of patients who demonstrated a meaningful clinical improvement from baseline. The study showed Serdaxin to be safe and well tolerated.

What really attracts me to this follow-up is another quote from Dr. Ahn: "These results contradict findings from previous studies of Serdaxin in depression, which is disappointing", he stated. Those previous studies, of course, are the ones that didn't reach significance, either, so I'd say that the latest results are right in line. But then, I have a different outlook on life. Serdaxin doesn't look like it'll do much for me, though.

Comments (12) + TrackBacks (0) | Category: Clinical Trials | The Central Nervous System


1. petros on December 5, 2011 9:28 AM writes...

Curiously Rexahn is also developing clavulanic acid (as Zoraxel) for the treatment of erectile dysfunction and (as Serdaxin) for Parkinson's disease

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2. Henning Makholm on December 5, 2011 9:45 AM writes...

"All groups showed an approximate -14 point improvement": Is that the same as saying "all groups got 14 points worse"? This drug is so bad that it causes even the adjacent placebo group to experience negative improvement??

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3. RB Woodweird on December 5, 2011 9:48 AM writes...

"The study showed Serdaxin to be safe and well tolerated."

In a couple of minutes the marketing department will realize that what they have is not a new and improved antidepressant but a new and improved placebo.

(Is Placebo trademarked yet?)

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4. bbooooooya on December 5, 2011 10:18 AM writes...

"Curiously Rexahn is also developing clavulanic acid (as Zoraxel) for the treatment of erectile dysfunction"

That should be the winner! I can just imagine the CEO talking about the marketing potential of using clavulinic acid to treat ED.....

Sadly, if they want to raise another $10 million in a secondary offering (for example, to ensure the continued $350,000 salary for the CEO) the good folks at Rodman & Renshaw are there to help them out.

I have no idea how these people sleep at night.

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5. MTK on December 5, 2011 10:23 AM writes...

I love that Dr. Ahn has named the company after himself, Rexahn. That's old school.

I'm surprised that the drug isn't called Serdaxahn for depression and Zoraxahn for ED.

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6. BioBearHedge on December 5, 2011 10:49 AM writes...

Thanks Derek! The stock has taken a 50% price cut in the last month and will most likely go down even more. At a price share of $0.50 it is going be difficult to raise money through an offering. According to their web site, they did a little bit of everything in R&D with almost the same authors in every publication. After looking at the data, it appears they are not very good in any particular indication. I think the company has little potential and is a good short candidate particularly if the stock reverse splits. I am wondering if the plan was to pump Serdaxin and sell their stock before clinical trial data came out?

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7. David Formerly Known as a Chemist on December 5, 2011 11:08 AM writes...

This entire story made me depressed. I took an Augmentin, but it didn't help.

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8. idiotraptor on December 5, 2011 11:09 AM writes...

Derek, since you are returning to the topic of snake oil therapeutics, I was wondering if you have given Nativis a recent look? Your post just prompted me to visit their website. No links there now to development programs, pedigrees of their executive management, videos of folks in lab coats pipetting blue liquids..

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9. Polynices on December 5, 2011 11:23 AM writes...

You say, "Serdaxin doesn't look like it'll do much for me". But pretty clearly it'll provide you with entertainment. That's something!

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10. anchor on December 5, 2011 12:45 PM writes...

I am completely flabbergasted that this Ahn guy was able to hoodwink the whole scientific community! He is indeed a true believer, I suppose! May be after all "money talks and BS walks".

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11. Anonymous on December 5, 2011 2:33 PM writes...

At #7. David: Of course Augmentin did not work for you. The amoxicillin in it is known not to be statistically significant from placebo in MAKING people depressed. Clearly the amoxicillin and clavulanic acid in Augmentin therefore cancelled each other out. You need to take the clavulanic acid by itself.

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12. petros on December 6, 2011 5:40 AM writes...

But surely #7 David should have got a rise out of the Augementin even if it didn;t cheer him up!

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