Admission to trading on the London Stock Exchange

NOT INTENDED TO PROMOTE THE SALE OF ANY SECURITIES, AND NOT FOR PUBLICATION,
DISTRIBUTION OR RELEASE, IN WHOLE OR IN PART, DIRECTLY OR INDIRECTLY, IN OR INTO
THE UNITED STATES (INCLUDING ITS TERRITORIES AND POSSESSIONS, ANY STATE OF THE
UNITED STATES AND THE DISTRICT OF COLUMBIA), AUSTRALIA, CANADA, JAPAN OR ANY
OTHER JURISDICTION WHERE IT IS UNLAWFUL TO DISTRIBUTE THIS ANNOUNCEMENT OR
ANY COPY OF IT

FOR IMMEDIATE RELEASE

18 March 2014

Circassia Pharmaceuticals plc
Admission to trading on the London Stock Exchange

Further to its announcements on 13 March 2014 relating to its initial public offering (the “Offer”),
Circassia Pharmaceuticals plc (“Circassia” or the “Company”), a clinical-stage specialty
biopharmaceutical company, is pleased to announce that its entire issued ordinary share capital of
187,422,379 ordinary shares (the “Shares”) has today been admitted to the premium listing segment
of the Official List of the UK Listing Authority and to trading on London Stock Exchange’s main
market for listed securities under the ticker “CIR.”.

Notes to editors:

Circassia is a specialty biopharmaceutical company focused on the development and
commercialisation of a range of immunotherapy products for the treatment of allergy. Established in
2006, the Company has used its innovative proprietary technology, ToleroMune® to develop a new
class of allergy therapies, Synthetic Peptide Immuno-Regulatory Epitopes (SPIREs), which Circassia
believes represents a step change to a new generation of allergy treatment. The Company’s portfolio
of product candidates is designed to treat a broad range of seasonal and perennial allergies. The lead
product candidate Cat-SPIRE, a new treatment for cat allergy, is currently in phase III development
and three other product candidates have completed phase IIb development. As Circassia continues
to grow, the Company remains focused on its founding principle – a commitment to improving
patients’ lives by controlling immune responses. Further information is available at:
www.circassia.co.uk.

Enquiries:

For further information please contact:
Circassia +44 (0)1865 405560
Steven Harris, Chief Executive Officer
Julien Cotta, Chief Financial Officer
Lara Flynn, Vice President of Corporate Affairs

Public Relations Adviser to Circassia

FTI Consulting +44 (0) 20 7831 3113
Ben Atwell
John Dineen

Global Co-ordinator, Sole Sponsor and Joint Bookrunner

J.P. Morgan Cazenove +44 (0) 20 7742 4000
Nicholas Hall
Gina Gibson

Joint Bookrunner

Peel Hunt +44 (0) 20 7418 8900
Jock Maxwell Macdonald

James Steel

Co-Manager
Canaccord Genuity +44 (0) 20 7523 8000
Lucy Tilley
Julian Feneley

Co-Manager
Shore Capital +44 (0) 20 7408 4090
Bidhi Bhoma
Edward Mansfield

Important notice

This announcement does not constitute or form part of any offer or invitation to sell or issue, or any
solicitation of any offer to purchase or subscribe for any Shares or any other securities, nor shall it
(or any part of it) or the fact of its distribution, form the basis of, or be relied on in connection with,
or act as an inducement to enter into, any contract therefor.

Neither this announcement nor any copy of it may be made or transmitted into the United States, or
distributed, directly or indirectly, in the United States. Neither this announcement nor any copy of it
may be taken or transmitted directly or indirectly into Australia, Canada or Japan or to any persons
in any of those jurisdictions, except in compliance with applicable securities laws. Any failure to
comply with this restriction may constitute a violation of United States, Australian, Canadian or
Japanese securities laws. The distribution of this announcement in other jurisdictions may be
restricted by law and persons into whose possession this announcement comes should inform
themselves about, and observe, any such restrictions. This announcement is not an offer of securities
for sale, or a solicitation of an offer to purchase securities in the United States, Australia, Canada
or Japan or in any jurisdiction to whom or in which such offer or solicitation is unlawful.

The securities to which this announcement relates have not been and will not be registered under the
US Securities Act of 1933, as amended (the “Securities Act”) or with any regulating authority or
under any applicable securities laws of any state or other jurisdiction of the United States, and may
not be offered or sold within the United States unless registered under the Securities Act or pursuant
to an exemption from, or in a transaction not subject to, the registration requirements of the
Securities Act and in compliance with applicable state law. There will be no public offer of the
securities in the United States.

The securities referred to herein have not been registered under the applicable securities laws of
Australia, Canada or Japan and, subject to certain exceptions, may not be offered or sold within
Australia, Canada or Japan or to any national, resident or citizen of Australia, Canada or Japan.
In any EEA Member State that has implemented Directive 2003/71/EC (together with any applicable
implementing measures in any Member State, the “Prospectus Directive”) other than the United
Kingdom, this announcement is only addressed to and is only directed at qualified investors in that
Member State within the meaning of the Prospectus Directive.

J.P. Morgan Cazenove, which is authorised by the Prudential Regulation Authority (“PRA”) and
regulated by the FCA and the PRA in the United Kingdom, and Peel Hunt, Canaccord Genuity and

Shore Capital, each of which is authorised and regulated by the FCA in the United Kingdom, are
acting exclusively for Circassia and no-one else in connection with the Offer, will not regard any
other person as their respective client in relation to the Offer, and will not be responsible to anyone
other than Circassia for providing the protections afforded to their respective clients, nor for
providing advice in relation to the Offer, advice in relation to Admission, the contents of this
announcement or any transaction, arrangement or other matter referred to herein.