, Volume 221, Issue 4, pp 601–610

Results of a proof-of-concept, dose-finding, double-blind, placebo-controlled study of RX-10100 (Serdaxin®) in subjects with major depressive disorder

  • Robert Riesenberg
  • Joshua Rosenthal
  • Leslie Moldauer
  • Christine Peterson
Original Investigation

DOI: 10.1007/s00213-011-2604-x

Cite this article as:
Riesenberg, R., Rosenthal, J., Moldauer, L. et al. Psychopharmacology (2012) 221: 601. doi:10.1007/s00213-011-2604-x



RX-10100 (Serdaxin®), a nonantibiotic small molecule beta-lactam compound, has shown potent antidepressant and anxiolytic activities in preclinical models. RX-10100 does not bind to the serotonin transporter or other receptors associated with monoamine activity. In microdialysis studies with rats, RX-10100 increased the release of dopamine and serotonin metabolites. A clinical proof-of-concept study was conducted to determine the clinical effectiveness of RX-10100 in treating depression.


This was a multicenter, randomized, double-blind, placebo-controlled, parallel group study of people with depression (n = 77; HAM-D-17 baseline score ≥ 20). Eligible subjects were randomly assigned to receive RX-10100 (5, 10, or 15 mg twice daily) or placebo for 8 weeks. Change from baseline in the MADRS total score was the primary endpoint.


Mean changes in MADRS scores were −46.0%, −37.9%, and −41.4%, for 5, 10, and 15 mg RX-10100, respectively, as compared with 43.1% for placebo. In subjects with severe depression (baseline MADRS ≥ 29; n = 28) scores improved 55.6% with 5 mg RX-10100 but only 34% with placebo (p = 0.041). In an analysis of responders (i.e., subjects with 50% change from baseline score), 64.3% of subjects treated with 5 mg RX-10100 responded. All doses of RX-10100 were well-tolerated.


In this proof-of-concept study, RX-10100 treatment (5 mg twice daily) improved MADRS scores in subjects with severe depression. RX-10100 does not appear to have many of the typical side effects of other antidepressants. These results indicate a need for larger studies further evaluating RX-10100 at 5 mg and lower doses.



Copyright information

© Springer-Verlag 2011

Authors and Affiliations

  • Robert Riesenberg
    • 1
  • Joshua Rosenthal
    • 2
  • Leslie Moldauer
    • 3
  • Christine Peterson
    • 4
  1. 1.Atlanta Center for Medical ResearchAtlantaUSA
  2. 2.Capital Clinical Research AssociatesRockvilleUSA
  3. 3.Segal Institute for Clinical ResearchMiamiUSA
  4. 4.Rexahn Pharmaceuticals, Inc.RockvilleUSA