Pharmacological Tolerance in the Treatment of Fragile X Syndrome

Pharmacological Tolerance in the Treatment of Fragile X Syndrome

With a $90,000 grant from FRAXA Research Foundation, Dr. Patrick McCamphill and Dr. Mark Bear at Massachusetts Institute of Technology (MIT) will further investigate drug tolerance and ways to overcome it. 

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Defining the Subcellular Specificity of Metabotropic Glutamate Receptor (mGluR5) Antagonists

Defining the Subcellular Specificity of Metabotropic Glutamate Receptor (mGluR5) Antagonists

With $217,500 in grants from FRAXA Research Foundation, Dr. Karen O’Malley and team studied the function of mGluR5 when it is inside cells. Many of the symptoms of fragile X Syndrome (FXS) are thought to arise due to overactive metabotropic glutamate receptor 5 (mGluR5) signaling, which is normally opposed by the protein missing in FXS, Fragile X Protein (FMRP).

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Mechanisms of Tolerance to Chronic mGluR5 Inhibition

Mechanisms of Tolerance to Chronic mGluR5 Inhibition

Over the past few years, both Novartis and Roche sponsored large-scale clinical trials of metabotropic glutamate receptor 5 (mGlu5) negative allosteric modulators (NAMs) to treat fragile X syndrome (FXS). With a $90,000 grant from FRAXA Research Foundation in 2015-2017, Dr. Mark Bear’s team will explore if mGlu5 NAMs dosed chronically causes tolerance, and if so, how it develops and to probe new avenues to prevent or circumvent it.

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Did Tolerance Result in Fragile X mGluR5 Clinical Trial Failures?

Did Tolerance Result in Fragile X mGluR5 Clinical Trial Failures?

Although the clinical trials failed to show efficacy in the patient population and Novartis and Roche discontinued their fragile X development programs, Dr. Senter has worked with Mark Bear, PhD to carefully review parent observations. Those caregiver reports suggested tolerance to mGlu5 antagonists antagonists developed quickly, consistent with some preclinical findings in the mouse model.

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New clue to Fragile X and autism found inside brain cells

Researchers led by Dr. Karen O’Malley at Washington University School of Medicine in St. Louis have published results of their work on mGluR5 and Fragile X syndrome. FRAXA Research Foundation provided funding for this work from 2009 until 2013. Pharmaceutical companies have developed therapeutic compounds to decrease signaling associated with the mGlu5 receptor, moderating its effects on brain cells’ volume knobs. But the compounds were designed to target mGlu5 surface receptors. In light of the new findings, the scientists question if those drugs will reach the receptors inside cells. “Our results suggest that to have the greatest therapeutic benefit, we may need to make sure we’re blocking all of this type of receptor, both inside and on the surface of the cell.”  “This should be a factor we consider when we design drugs to target brain cell receptors. Do we want to reach cell surface receptors, receptors inside the cell

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Social Behavior as an Outcome Measure for Fragile X Clinical Trials

Social Behavior as an Outcome Measure for Fragile X Clinical Trials

One of the features of the fragile X mouse model which is relevant to the human fragile X syndrome (and autism) is social behavior. Several tests show consistent social behavioral abnormalities in the fragile X mouse model. With a $140,000 grant from FRAXA Research Foundation in 2012-2013, Dr. Willemsen at Erasmus University used social behavior tests to measure the effectiveness of several drug strategies.

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Compound that Inhibits mGluR5 Corrects Signs of Fragile X in Adult Mice

A study finds that a new compound reverses many of the major symptoms associated with Fragile X syndrome (FXS). The paper is published in the April 12 issue of the journal Neuron, describes the exciting observation that the FXS correction can occur in adult mice, after the symptoms of the condition have already been established. Previous research has suggested that inhibition of mGlu5, a subtype of receptor for the excitatory neurotransmitter glutamate, may ameliorate many of the major symptoms of the disease. This study, a collaboration between a group at Roche in Switzerland, led by Dr. Lothar Lindemann, and Dr. Mark Bear’s MIT lab, used an mGlu5 inhibitor called CTEP to examine whether inhibition of mGlu5 could reverse FXS symptoms. The researchers gave CTEP to mice which model Fragile X. “We found that even when treatment with CTEP was started in adult mice, it reduced a wide range of FXS

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Defining the Subcellular Specificity of Metabotropic Glutamate Receptor (mGluR5) Antagonists

Defining the Subcellular Specificity of Metabotropic Glutamate Receptor (mGluR5) Antagonists

With $109,500 in grants from FRAXA Research Foundation over 5 years, Dr. Karen O’Malley of Washington University researches the relationship between fragile X syndrome and the functions of mGluR5.

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Bloomberg News: Roche Eureka Moment on Disorder

Bloomberg News: Roche Eureka Moment on Disorder

Researcher Luca Santarelli wasn’t sure what do to with an experimental medicine developed in the labs of his employer, Roche, until a 2007 meeting with a concerned father led to a “Eureka moment.” Mike Tranfaglia, whose son Andy has Fragile X, met Santarelli to present new research… By Dermot Doherty http://www.bloomberg.com/apps/news?pid=newsarchive&sid=a0S62zPmBtN0

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FRAXA Contributes $10,000 to NIH grant to Seaside Therapeutics

FRAXA Contributes $10,000 to NIH grant to Seaside Therapeutics

Randy Carpenter, MD Principal Investigator with Mark Bear, PhD, MIT Co-Investigator (2007)   Clinical development of mGluR5 Antagonists to Treat Fragile X Syndrome and Autism Seaside Therapeutics received a major grant from the NIH, with additional funding from FRAXA and Cure Autism Now (CAN) to develop STX107, a selective mGluR5 antagonist, as a treatment for fragile X. Unfortunately Seaside has since discontinued development of STX107.

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Transgenic Mouse Models of Fragile X Syndrome

Transgenic Mouse Models of Fragile X Syndrome

With $736,000 in grants from FRAXA Research Foundation over 2000-2007, Dr. Robert Bauchwitz at Columbia University developed 15 transgenic mouse models of fragile X syndrome, using them to evaluate a range of experimental treatments. Results published.

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