Why Did Fragile X Clinical Trials of mGluR Antagonists Fail?

Why Did Fragile X Clinical Trials of mGluR Antagonists Fail?
Drug Tolerance and Dose Range Problems May Have Been the CulpritsAndy Tranfaglia and his dad, Mike Tranfaglia In my opinion, the Fragile X clinical trials of AFQ056 sponsored by Novartis failed because of a dose range that was inadequate for fragile X, and because of the unexpected development of tolerance. Dosage problems are relatively easy to correct, but tolerance to the degree we observed may be a kind of fatal flaw, at least if we're talking about mGluR5 antagonists.  The mGluR Theory of Fragile X is still probably correct; it's just that no one (least of all Novartis) expected tolerance to this drug -- indeed, I'm not sure they would agree that's what happened. I think we saw a much better response than most people because our son, Andy, was also on minocycline, effectively augmenting the response, and perhaps delaying the development of tolerance.  This may be a clue to understanding the mechanism of tolerance,Read more

Role of Excessive Protein Synthesis in the Ontogeny of FXS

Role of Excessive Protein Synthesis in the Ontogeny of FXS

With a $90,000 grant from FRAXA Research Foundation in 2010-2011, Dr. Mark Bear and Dr. Miquel Bosch tested the simple hypothesis that the excessive rate of protein synthesis is not a consequence but the primary cause of the structural alterations occurring in fragile X syndrome.

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Metabotropic Glutamate Receptor Function in Fragile X Knockout Mice

Metabotropic Glutamate Receptor Function in Fragile X Knockout Mice

With $143,000 in grants from FRAXA Research Foundation from 2004-2006, Drs. Walter Kaufmann, Richard Huganier, Paul Worley, and David Lieberman at Johns Hopkins University studied the molecular dynamics of mGluRs in areas involved in cognition in the fragile X knockout mouse.

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Role of Experience in Regulating Levels of the Fragile X Protein

Role of Experience in Regulating Levels of the Fragile X Protein

FRAXA Research Grant to Kenneth J. Mack, MD, PhD — Mayo Clinic with Peter K. Todd, MD, PhD, Postdoctoral Fellow   FRAXA Awards: $29,000 in 2001 $20,000 in 2000 Final Report on Dr. Mack’s Project While a professor at University of Wisconsin-Madison, Dr. Mack investigated whether and how FMRP levels are regulated in response to neuronal stimulation in vivo (in live animals). He looked at the effects of seizures and of experience in his experiments. Dr. Mack and colleagues published their findings in the Proceedings of the National Academy of Sciences: The fragile X mental retardation protein is required for type-I metabotropic glutamate receptor-dependent translation of PSD-95 Peter K. Todd, Kenneth J. Mack, and James S. Malter PNAS | November 25, 2003 | vol. 100 | no. 24

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Synaptic Plasticity and Olfactory Learning in Fragile X

Synaptic Plasticity and Olfactory Learning in Fragile X

With a $40,000 grant from FRAXA Research Foundation in 2000, Dr. John Larson and his team at the University of Illinois Chicago used olfaction (sense of smell) in mice as a neuro-behavioral model system for human memory. They characterized olfactory sensitivity, learning, and memory in FMR1 knockout mice as compared to wild-type (normal control) mice.

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