Indivior announced that Indivior UK Limited has entered into a strategic collaboration with Addex Pharma S.A., a wholly-owned subsidiary of Addex Therapeutics (SIX: ADXN) ("Addex"), in the field of GABAB positive allosteric modulators (PAMs). GABAB PAMs have demonstrated preclinical efficacy and tolerability in animal models for alcohol use disorder (AUD) and cocaine use disorder (CUD)1,2. The collaboration includes an exclusive global license to lead candidate ADX71441, which is a novel, first-in-class, oral, small molecule and is expected to enter Phase 1 trials in 2018. The collaboration also includes exclusive global license to backup GABAB PAM compounds, as well as a research collaboration focused on discovering additional GABAB PAMs. The Addex GABAB program was recently awarded a $5.3 million grant by the National Institute on Drug Abuse ("NIDA") to support the development of ADX71441 in CUD3.

Under the terms of the agreement, Indivior is making an upfront payment to Addex of $5 million, and will also invest in research funding over the next two years to discover additional GABAB PAM compounds commercially-viable to treat addiction. Potential milestone payments to Addex could total $330 million over time if all development, regulatory and sales goals are achieved.

"As part of our leadership position in addiction, among the key priorities we are pursuing is continuing to review and invest in promising new treatments for this chronic and relapsing disease," said Shaun Thaxter, CEO of Indivior. "Modulation of the GABAB receptor pathway is an attractive mechanism, particularly for the potential it holds in advancing treatments for AUD and CUD. Further, we are excited about this new strategic collaboration with Addex to discover additional compounds targeting the GABAB receptor pathway, which will complement the current pipeline efforts we have underway to develop novel treatments for addiction."

"We believe Addex has the most advanced science in the area of GABAB allosteric modulation and look forward to rapidly advancing lead compound, ADX71441, into Phase 1 trials," said Christian Heidbreder, Chief Scientific Officer of Indivior. "As we continue to collaborate with the Addex team, we believe there is great potential for additional compounds to be discovered and developed related to this important mechanism for addiction science."

Addex's GABAB PAMs Program Focused on Addiction

Long-term exposure to drugs of abuse causes adaptive changes in several neurotransmitter systems, including gamma-aminobutyric acid (GABA) receptors. Research has shown that exposure to psychostimulants depresses the normal function of the GABAB receptor signaling in the mesolimbic dopaminergic system4, which plays a role in the positive reinforcing properties of several drugs of abuse and may also contribute to the negative reinforcing effects associated with their withdrawal5. Therefore, full agonists aimed at the orthosteric site on the GABAB receptor have been the target for the development of pharmacotherapies for AUD and CUD2.

The efficacy of these full agonists at the orthosteric site on the GABAB receptor, however, are limited due to tolerance and undesired side effects, including sedation, myorelaxing activity and hypothermia. Unlike orthosteric agonists, positive allosteric modulators (PAMs) work by only enhancing the activity of GABAB receptors when and where needed physiologically. As such, GABAB PAMs are expected to have significantly less undesired side effects than full GABAB receptor agonists and to be suitable for long-term treatment without challenges related to tolerance6.

About Indivior

Indivior is a global specialty pharmaceutical company with a 20-year legacy of leadership in patient advocacy and health policy while providing education on evidence-based treatment models that have revolutionized modern addiction treatment. The name is the fusion of the words individual and endeavour, and the tagline "Focus on you" makes the Company's commitment clear. Indivior is dedicated to transforming addiction from a global human crisis to a recognized and treated chronic disease. Building on its global portfolio of opioid dependence treatments, Indivior has a strong pipeline of product candidates designed to both expand on its heritage in this category and address other chronic conditions and co-occurring disorders of addiction, including AUD and schizophrenia. Headquartered in the United States in Richmond, VA, Indivior employs more than 900 individuals globally and its portfolio of products is available in over 40 countries worldwide.