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.

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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.

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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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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.Read more

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

AFQ056 Fragile X Clinical Trial showed Negative Results 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! While the company has already announced that the adult and adolescent trials failed to meet their pre-designated endpoints, the numbers looked really bad. This wasn't a case of the drug working, but placebo effects leading to an outcome that wasn't statistically significant; in this case, the effect of the drug was statistically significant, but in the wrong direction! So, what went wrong? The evidence for using mGluR5 antagonists in Fragile X was really strong going into these trials---in fact, about as good as it ever gets. The drug itself was an advanced compound that had been studied extensively.Read more

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. When will the Trials be Finished? It all depends on enrollment. Trials need to have a certain number of people (a number determined before the trial starts) complete the trial before they can analyze the data and present results to the FDA. It all depends on how many people sign up to participate. Is There Assistance for Travel? Many trials provide financial assistance for travel expenses. The amount depends on how far you have to travel. Please check with the coordinatorRead more

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 FXSRead more