GSK receives complete response letter from US FDA for use of mepolizumab in COPD patients

Issued: London UK – LSE Announcement

GlaxoSmithKline plc (LSE/NYSE: GSK) today received a complete response letter (CRL) from the US FDA regarding its application for mepolizumab as an add-on treatment to inhaled corticosteroid-based maintenance treatment for the reduction of exacerbations in patients with chronic obstructive pulmonary disease (COPD), guided by blood eosinophil counts.

The CRL states that more clinical data are required to support an approval. GSK will work closely with the FDA to determine the appropriate next steps for the supplementary biologics licence application (sBLA).

About mepolizumab

First approved in 2015 for severe eosinophilic asthma, and also licenced for EGPA in the US, mepolizumab is the first-in-class monoclonal antibody that targets IL-5. It is believed to work by preventing IL-5 from binding to its receptor on the surface of eosinophils. Inhibiting IL-5 binding in this way reduces blood eosinophils.

Mepolizumab has been studied in over 3000 patients in 16 clinical trials across a number of eosinophilic indications and is currently being investigated for severe hypereosinophilic syndrome and nasal polyposis, in addition to the sBLA filed for the treatment of patients with COPD.

GSK in respiratory disease

GSK has led the way in developing innovative medicines to advance the management of asthma and COPD for nearly 50 years. Over the last five years we have launched six innovative medicines responding to continued unmet patient need, despite existing therapies. This is an industry-leading portfolio in breadth, depth and innovation, developed to reach the right patients, with the right treatment.

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Cautionary statement regarding forward-looking statements
GSK cautions investors that any forward-looking statements or projections made by GSK, including those made in this announcement, are subject to risks and uncertainties that may cause actual results to differ materially from those projected. Such
factors include, but are not limited to, those described under Item 3.D Principal risks and uncertainties in the company's Annual Report on Form 20-F for 2017.