Press Release: Addex ADX71149 Receives IND Approval to Start a Phase 2a Clinical Study in Epilepsy

First patient treated with ADX71149 (JNJ-40411813) scheduled for Q2 2021

Geneva, Switzerland, January 21, 2021 --

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Addex Therapeutics (SIX: ADXN and Nasdaq: ADXN), a clinical-stage

pharmaceutical company pioneering allosteric modulation-based drug

discovery and development, today announced that its partner Janssen

Pharmaceuticals, Inc., part of the Janssen Pharmaceutical Companies of

Johnson & Johnson, has received FDA's Investigational New Drug (IND)

approval to begin a Phase 2a proof of concept study with the selective

metabotropic glutamate type 2 (mGlu2) receptor positive allosteric

modulator (PAM), JNJ-40411813 (ADX71149), in patients with epilepsy. The

first patient is expected to be treated during Q2 2021.

"IND approval for the mGlu2 epilepsy study is great news to start 2021

and will be the first of three clinical studies we expect to be initiate

this year," said Tim Dyer, CEO of Addex. "There is a great opportunity

for an allosteric modulation approach in this difficult disease. We'd

like to thank the team involved for their continued support and moving

quickly to get this clinical study ready for patient enrolment."

The multi-center study will assess the efficacy, safety, tolerability

and pharmacokinetics of adjunctive JNJ-40411813 (ADX71149)

administration in patients with focal onset seizures with suboptimal

response to levetiracetam. The primary objective of the study is to

evaluate the efficacy of JNJ-40411813 (ADX71149) in combination with

levetiracetam using a time-to-event endpoint.

"There is a strong preclinical rationale for mGlu2 PAM in epilepsy,

including a true synergistic effect with levetiracetam," said Robert

Lütjens, Head of Discovery Biology of Addex. "A highly synergistic

anti-epileptic effect was observed when the two drugs were administered

together, and we look forward to seeing this effect in epilepsy

patients."

Glutamate, mGlu2 Receptors and Epilepsy

Glutamate is the primary excitatory neurotransmitter in the brain and

plays a key role in the initiation and spread of seizures. When

activated, the mGlu2 receptor decreases the release of glutamate and

consequently helps to maintain neurotransmitter balance. In the presence

of agonist-induced activation, positive allosteric modulation of mGlu2

receptors could result in the normalization of the excessive glutamate

release seen during a seizure. There is still an urgent need for more

effective treatments for epilepsy, with improved tolerability and

safety. JNJ-40411813 (ADX71149) was described in the Eilat 15 conference

summary review as one of the most promising novel approaches currently

in development (Bialer et al., 2019. Epilepsia). Proof of concept data

with JNJ-40411813 (ADX71149) and other mGlu2 PAMs in animal models of

epilepsy have been published in peer-reviewed journals (Metcalf et al.,

2017 and 2018. Epilepsia).

About Addex Therapeutics

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Addex Therapeutics is a clinical-stage pharmaceutical company focused on

the development and commercialization of an emerging class of novel

orally available small molecule drugs known as allosteric modulators for

neurological disorders. Allosteric modulators offer several potential

advantages over conventional non-allosteric molecules and may offer an

improved therapeutic approach to conventional "orthosteric" small

molecule or biological drugs. Addex's allosteric modulator drug

discovery platform targets receptors and other proteins that are

recognized as essential for therapeutic intervention. Addex's lead drug

candidate, dipraglurant (mGlu5 negative allosteric modulator or NAM), is

poised to start a pivotal registration clinical trial for Parkinson's

disease levodopa induced dyskinesia (PD-LID) in H1 2021. Addex is also

investigating dipraglurant's therapeutic use in blepharospasm (a type of

dystonia), for which a clinical trial is expected to be initiated in H1

2021. Addex's third clinical program, ADX71149 (mGlu2 positive

allosteric modulator or PAM), developed in collaboration with Janssen

Pharmaceuticals, Inc, is scheduled to enter a phase 2a proof of concept

clinical study for the treatment of epilepsy in Q2 2021. Addex's GABAB

PAM program has been licensed to Indivior PLC for the treatment of

addiction. Preclinical programs include GABA(B) PAM for CMT1A, mGlu7

NAM for PTSD, mGlu2 NAM for mild neurocognitive disorders, mGlu4 PAM for

Parkinson's disease and mGlu3 PAM for neurodegenerative disorders. Addex

is listed on the SIX Swiss Exchange and the NASDAQ Capital Market and

trades under the ticker symbol "ADXN".

Press Contacts:

Tim Dyer Mike Sinclair

Chief Executive Officer Partner, Halsin Partners

Telephone: +41 22 884 15 55 +44 (0)20 7318 2955

Email: mailto:PR@addextherapeutics.com PR@addextherapeutics.com mailto:msinclair@halsin.com msinclair@halsin.com

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as of the date of this announcement. The forward-looking statements made

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release publicly any revisions or updates to these forward-looking

statements to reflect events, circumstances, or unanticipated events

occurring after the date of this announcement except as required by law

or by any appropriate regulatory authority.

(END) Dow Jones Newswires

January 21, 2021 01:00 ET (06:00 GMT)