Drug Tolerance is Likely Culprit Behind the Failure of MGluR5 Clinical Trials

Drug Tolerance is Likely Culprit Behind the Failure of MGluR5 Clinical Trials

We have long suspected that the clinical trials of mGluR5 blockers from Novartis and Roche failed because the drug triggered tolerance, losing effect over time. With a $90,000 grant from FRAXA, Dr. Patrick McCamphill, a Postdoctoral Fellow in the MIT lab of Dr. Mark Bear, is investigating. He does indeed find tolerance, and now he is looking for ways to overcome it.

Bear lab (Bear 3rd from left, McCamphill on right)Read more

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 over 2018-2019, Dr. Patrick McCamphill, postdoctoral fellow in Dr. Mark Bear’s lab at Massachusetts Institute of Technology (MIT), is investigating drug tolerance to mGluR5 antagonists, arbaclofen, and other potential Fragile X treatments. He is also exploring ways to overcome it.

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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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Metformin, Diabetes Drug, Potential Fragile X Treatment

Metformin, Diabetes Drug, Potential Fragile X Treatment

“We treated mice with metformin and corrected all the core Fragile X deficits. We are optimistic about using metformin in human clinical trials. This is a generic drug with few side effects” says Nahum Sonenberg, PhD, James McGill Professor, Department of Biochemistry, McGill Cancer Center, McGill University.

Nahum Sonenberg, PhD, 2017 Fragile X Research GrantRead more

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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Roche reports clinical trial negative results

Roche reports clinical trial negative results
Roche has shared the sad news that their clinical trials in Fragile X have been unsuccessful. They will host a Webcast on Thursday, September 18, from 12:30pm - 1:30pm (EDT) to explain the results. For details and dial-in information please see this letter from Luca Santarelli, the Head of Neuroscience, Ophthalmology and Rare Diseases at Roche Pharma Research and Early Development on Roche`s Research Program on Fragile X. After the webcast, FRAXA will post a Q&A about what we've learned, other clinical trials in progress, and other promising treatment strategies.Roche Fragile X programRead more

Fragile X Clinical Trial: Novartis Trial Results Are In, and They’re Not Pretty

This year’s Gordon Conference just finished, and Novartis presented their results for the first time (though advisors and advocates had been given a private peak months ago.) To say that the trial results for AFQ056 were disappointing would be the understatement of the century!

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Clinical Trials FAQ ← Frequently Asked Questions

Question: How Do Families Decide Which Trial is Best for Them? Answer: Each of the trials has different requirements for joining, so many – if not most – people will only be eligible for one trial after screening. The best way to approach this is to call the clinic contact closest to your area and discuss this with him/her. Age, weight, current medications, behavior, and IQ are all factors.

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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, describing 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.

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