CAMBRIDGE, UK ? 9 August 2021 ??Mission Therapeutics?(?Mission?), a drug discovery and development company focused on targeting the ubiquitin pathway, and?AbbVie?(?AbbVie?)(NYSE: ABBV) today announced progression of selected deubiquitylating enzyme (DUB) targets into the next phase of research in their neurodegenerative disease collaboration. In the second major milestone of the Companies? research and preclinical development collaboration, AbbVie has nominated two DUB targets to progress to the next stage of drug discovery. This selection follows supportive data from?in vitro?and?in vivo?Alzheimer?s and Parkinson?s disease models. As a result of the nomination, Mission will receive a milestone payment of $20 million from AbbVie. Alzheimer?s and Parkinson?s diseases are the most common neurological disorders worldwide, with over 50 million people living with dementia and Alzheimer?s disease, and 10 million more with Parkinson?s. While there are treatments to help reduce symptoms, there are no treatments available to help stop or reverse progression. Both Alzheimer?s and Parkinson?s are associated with the accumulation of misfolded, proteins in the brain, which are believed to cause impaired function and death of nerve cells. DUBs can help to maintain cell health by regulating the degradation of these proteins. Under the terms of the agreement,?first announced in 2018, Mission and AbbVie are collaborating to identify novel DUB targets and discover associated inhibitor compounds for neurodegenerative diseases. AbbVie has the option to gain exclusive rights to develop and commercialize inhibitors of selected DUB targets and will pay Mission success-based milestones as well as royalty payments for each commercialized product. Commenting on the development, Dr Anker Lundemose, Mission?s CEO, said: ?We are delighted to have reached this next major milestone in our collaboration with AbbVie and receive the $20 million milestone ? this represents a big step forward for Mission and further highlights DUBs as targets for drug development. The successful and timely progression of two DUB targets into the drug discovery phase is further validation of our platform. We look forward to the continuation of this great neurodegenerative disease collaboration.? Dr Eric Karran, Vice President,?Neuroscience Discovery Research, AbbVie commented: ?There is an urgent need for treatments that can make tangible and lasting improvements to the lives of Alzheimer?s and Parkinson?s patients. Our collaboration with Mission has the potential to identify novel therapeutic options for neurodegenerative disorders. We have had a great experience working with Mission and are pleased to be able to continue to draw on their valued expertise as we enter the next phase of drug development.? ? ENDS ? ? FOR MORE INFORMATION:

Mission Therapeutics Ltd Anker Lundemose MD PhD Chief Executive Officer Tel: +44 (0)1223 607 340? AbbVie Media Frank Benenati +1 (224) 688-4169 frank.benenati@abbvie.com

Instinctif Partners Melanie Toyne-Sewell / Katie Duffell Tel: +44 (0) 20 7457 2013 missiontherapeutics@instinctif.com?

? ?NOTES TO EDITORS: About Mission Therapeutics Mission Therapeutics is an early-stage drug development company targeting the ubiquitin pathway for the treatment of kidney disease, neurodegenerative disease, rare mitochondrial diseases and fibrosis. The Company has built a leading platform for the discovery and development of first-in-class, small molecule drugs that selectively target deubiquitylating enzymes (DUBs) ? an emerging drug class that is attracting significant commercial interest in the area of protein homeostasis. Mission has strong links with key academic and research centers, including Prof. Steve Jackson?s Cancer Research UK Laboratories at the University of Cambridge Gurdon Institute, and leading UK centres in neurodegenerative diseases. The Company also has secured major industry partnerships, including its collaboration with AbbVie in November 2018, for the research and preclinical development of specified DUB inhibitors for the treatment of Alzheimer?s Disease and Parkinson?s Disease. The Company is managed by a team with broad international, commercial and clinical-science experience. To date the Company has received ?73 million / $101 million in funding and its investors comprise blue chip institutional and corporate investors including: Pfizer Venture Investments, Sofinnova Partners, Roche Venture Fund, SR One, IP Group and Rosetta Capital. Mission Therapeutics was founded in 2011 and is based at the Babraham Research Campus, Cambridge, UK. For more information, please visit our website,?www.missiontherapeutics.com, or follow us on?Twitter?or?LinkedIn. About AbbVie AbbVie?s mission is to discover and deliver innovative medicines that solve serious health issues today and address the medical challenges of tomorrow. We strive to have a remarkable impact on people?s lives across several key therapeutic areas: immunology, oncology, neuroscience, eye care, virology, women?s health and gastroenterology, in addition to products and services across its Allergan Aesthetics portfolio. For more information about AbbVie, please visit us at www.abbvie.com. Follow @abbvie on?Twitter,?Facebook,?Instagram,?YouTube?and?LinkedIn.