INFORMATION STATEMENT Prothena Corporation plc Ordinary Shares (par value $0.01 per share) This information statement is being furnished in connection with the separation of a substantial portion of the drug discovery bu

INFORMATION STATEMENT

Prothena Corporation plc

(par value $0.01 per share)

statement is being furnished in connection with the separation of a substantial portion of the drug discovery business platform of Elan Corporation, plc ( Elan ), which we describe more specifically herein and which we refer to as the

Prothena Business, into a new company, Prothena Corporation plc ( Prothena ), an Irish public limited company. The separation of the Prothena Business from Elan will be completed through a demerger under Irish law.

The demerger will be effected by Elan transferring the Prothena Business to Prothena, in exchange for Prothena issuing directly to the holders of Elan ordinary shares and Elan American Depositary Shares ( ADSs ), on a pro rata

basis, Prothena ordinary shares representing 99.99% of Prothena s outstanding shares (with the remaining 0.01% of Prothena s outstanding shares, which were previously issued to the original incorporators of Prothena and which we refer to

as the incorporator shares, being mandatorily redeemed by Prothena after the demerger as described below). Prothena s issuance of 99.99% of its outstanding shares will constitute a deemed in specie distribution,

or a distribution in the form of assets other than cash (in this case, Prothena shares), by Elan to holders of record of Elan ordinary shares and Elan ADSs as of 11:59 p.m., Dublin Time, on December 14, 2012, which will be the record date.

Pursuant to the demerger, each Elan shareholder will receive 1 Prothena ordinary share for every 41 Elan ordinary shares or Elan ADSs held as of the record date. We refer to this demerger, including the transfer of the Prothena Business to Prothena

and the pro rata issuance by Prothena of 99.99% of its outstanding shares, as the distribution and we refer to the reorganization transactions (which will precede the distribution) and the distribution collectively as the

separation and distribution. The distribution is expected to be effective at 11:59 p.m., Dublin Time, on December 20, 2012, subject to certain conditions described in this information statement; provided, that if the

conditions have not been satisfied or waived on or before the effective date of the distribution, the distribution date may be extended until the conditions are satisfied or waived.

Prior to the separation and distribution, a wholly-owned subsidiary of Elan agreed (conditioned on the consummation of the separation and

distribution) to subscribe for newly-issued ordinary shares of Prothena, representing 18% of the outstanding ordinary shares of Prothena (as calculated immediately following the consummation of such subscription), for a cash payment to Prothena of

$26.0 million. This subscription will be consummated immediately following the separation and distribution. Immediately after the consummation of Elan s subscription for 18% of Prothena s outstanding ordinary shares (as calculated

immediately following the consummation of such subscription), the incorporator shares will be mandatorily redeemed by Prothena pursuant to their terms for their initial subscription price, and cancelled. We refer to the separation and distribution,

together with Elan s subsequent subscription for an aggregate of 18% of our outstanding ordinary shares (as calculated immediately following the consummation of such subscription) and the redemption of the incorporator shares, as the

Prothena Transactions.

We will not distribute any fractional Prothena ordinary shares. Instead, the distribution

agent will aggregate fractional shares into whole shares, sell the whole shares in the open market at prevailing market prices, and distribute the aggregate net cash proceeds from the sales on a pro rata basis to each holder who would

otherwise have been entitled to receive a fractional share in the distribution.

For U.S. federal income tax purposes, Elan

expects to receive an opinion on the closing date of the Prothena Transactions from each of Cadwalader, Wickersham & Taft LLP and KPMG LLP to the effect that the separation and distribution should qualify as a reorganization under section

368(a)(1)(D) of the Internal Revenue Code of 1986, as amended (the Code ), and the distribution, as such, should qualify as a distribution of our ordinary shares to Elan shareholders under section 355 of the Code. If the separation and

distribution are so treated, Elan shareholders should not recognize any gain for U.S. federal income tax purposes on the receipt of our ordinary shares, except with respect to cash received in lieu of fractional Prothena ordinary shares. However,

the separation and distribution are not conditioned on the receipt of an opinion confirming these expected U.S. federal income tax consequences, nor will Elan seek a ruling from the United States Internal Revenue Service ( IRS ) addressing

the separation and distribution and related transactions. See The Separation and Distribution Material U.S. Federal Income Tax Consequences of the Separation and Distribution and Related Transactions.

For Irish tax purposes, Elan expects to receive an opinion on the closing date of the separation and distribution from KPMG Ireland to the

effect that, save with respect to the receipt of cash in lieu of fractional entitlements to Prothena ordinary shares, the distribution should not give rise to a taxable event for those classes of Irish shareholders specifically referred to in the

section below Material Irish Tax Consequences of the Distribution. However, the distribution is not conditioned on the receipt of an opinion confirming these expected Irish tax consequences, nor will Elan seek a specific confirmation

from the Revenue Commissioners of Ireland in respect of the anticipated tax treatment of the distribution.

2012, Elan shareholders voted to approve the declaration of the deemed in specie distribution by Elan described above. No further shareholder approval of the separation and distribution is required or sought. We are not asking you for a proxy

and you are requested not to send us a proxy. Elan shareholders will not be required to pay for the Prothena ordinary shares to be received by them in the separation and distribution, or to surrender or to exchange Elan ordinary shares or Elan ADSs

in order to receive Prothena ordinary shares, or to take any other action in connection with the separation and distribution.

There is currently no trading market for Prothena ordinary shares, although we expect that a limited market, commonly known as a

when-issued trading market, will develop shortly following the record date for the distribution, and we expect regular-way trading of Prothena ordinary shares to begin on the first trading day following the completion of the

separation and distribution. Our ordinary shares have been approved for listing on The Nasdaq Global Market under the symbol PRTA.

this information statement, you should carefully consider the matters described under the caption Risk Factors beginning on page 21.

Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved these securities or

determined if this information statement is truthful or complete. Any representation to the contrary is a criminal offense.

This information statement does not constitute an offer to sell, or a solicitation of an offer to buy, any securities.

The date of this information statement is December 17, 2012.

This information statement was first mailed to Elan shareholders on or about December 19, 2012.

Industry and Market Data

This information statement includes industry and trade association data, forecasts and information that we have prepared based, in part, upon data, forecasts and information obtained from independent

trade associations, industry publications and surveys and other independent sources available to us. Some data are also based on our good faith estimates, which are derived from management s knowledge of the industry and from independent

sources. These third-party publications and surveys generally state that the information included therein has been obtained from sources believed to be reliable, but that the publications and surveys can give no assurance as to the accuracy or

completeness of such information.

Trademarks and Service Marks

Unless otherwise indicated, the logos, trademarks, trade names, and service marks mentioned in this information statement are currently

the property of, or are used with the permission of, Prothena or Elan. We own or have rights to use the trademarks, service marks and trade names that we use in conjunction with the operation of our business. Some of the more important trademarks

that we own or have rights to use that appear in this information statement may be registered in the United States and other jurisdictions. Each trademark, trade name or service mark of any other company appearing in this information statement is

owned by such company (including the trademark VELCRO, which is owned by Velcro Industries, B.V.).

About this Information

Except as otherwise indicated or unless the context otherwise requires, all references to we,

our, us, Prothena or the Company refer to Prothena Corporation plc, an Irish public limited company, together with its consolidated subsidiaries. References in this information statement to

Elan refer to Elan Corporation, plc and its consolidated subsidiaries (other than, for all periods following the separation and distribution, Prothena). All references to we, our, us,

Prothena or the Company in the context of historical results refer to the Prothena Business. Except as otherwise indicated or unless the context otherwise requires, the

information included in this information statement, including the combined financial statements of Prothena, which are comprised of the assets and liabilities of the Prothena Business, assumes

the completion of all the transactions referred to in this information statement in connection with the separation of the Prothena Business from Elan (including the issuance of Prothena ordinary shares to Elan immediately following the separation

This information statement is being furnished solely to provide information to Elan shareholders

who will receive ordinary shares of Prothena in connection with the separation and distribution. It is not provided as an inducement or encouragement to buy or sell any securities. You should not assume that the information contained in this

information statement is accurate as of any date other than the date set forth on the cover. Changes to the information contained in this information statement may occur after that date, and we undertake no obligation to update the information

contained in this information statement, unless we are required by applicable securities laws to do so.

The following is a summary of some of the information contained in this information statement. This summary is included for

convenience only and should not be considered complete. This summary is qualified in its entirety by the more detailed information contained elsewhere in this information statement. You should read the entire information statement carefully,

including the risks discussed under Risk Factors beginning on page 21 and the financial statements and notes thereto included elsewhere in the information statement. Some of the statements in this summary constitute forward-looking

statements. See Forward-Looking Statements.

Prothena s business consists of a substantial portion of Elan Corporation, plc s former drug discovery business platform,

including the following former wholly owned subsidiaries of Elan and related tangible assets and liabilities, which we refer to as the Prothena Business:

Neotope Biosciences strategy is to apply its expertise

in generating novel therapeutic antibodies, working with a broad range of collaborators in specific disease models, to select candidates for further clinical development. Neotope Biosciences portfolio of targets includes alpha-synuclein for

the potential treatment of synucleinopathies, such as Lewy body dementia and Parkinson s disease, MCAM for autoimmune disease and metastatic cancers such as melanoma, and tau for Alzheimer s disease and other tauopathies. Neotope

Biosciences also has a program focused on the potential treatment of type 2-diabetes.

Neotope Biosciences,

Onclave, and Prothena US are collectively referred to herein as the Prothena Subsidiaries.

We intend to advance and develop novel and proprietary therapeutic antibodies discovered by our scientists internally. Our goal is to be a

leading biotechnology company focused on the discovery and development of novel antibodies for the potential treatment of a broad range of diseases that involve protein misfolding or cell adhesion. Key elements of our strategy to achieve this goal

Reasons for the Separation and Distribution

The board of directors of Elan has determined that the separation and distribution are in the best interests of Elan and its shareholders because it will provide both Elan and Prothena the following key

benefits: (i) greater strategic focus of financial resources and management s efforts, (ii) direct and differentiated access to capital resources, (iii) enhanced investor choice through investment opportunities in two separate

companies and (iv) enhanced management incentive tools.

Our new company faces both general and specific risks and uncertainties that are described in detail under Risk Factors beginning on page 21. These risks and uncertainties relate to:

We urge you to see Risk Factors beginning on page 21 for a more thorough

discussion of risk factors associated with our business, the separation and distribution and our ordinary shares.

Prothena Corporation plc was incorporated as a private limited company, under the name Neotope Corporation

Limited , under the laws of Ireland on September 26, 2012 and re-registered as a public limited company and changed its name to Neotope Corporation plc on October 25, 2012. On November 1, 2012, the shareholders of

Prothena resolved, by way of special resolution, to change the name of the company to Prothena Corporation plc , and this was approved by the Irish Registrar of Companies on November 7, 2012. Our principal executive offices are located at

650 Gateway Boulevard, South San Francisco, California. Our telephone number is (650) 837-8550. Our registered office is 25-28 North Wall Quay, Dublin 1, Ireland. Our website address is www.prothena.com. Information contained on any website

referenced in this information statement is not incorporated by reference in this information statement or in the Form 10 of which this information statement is a part.

Emerging Growth Company

We are an Emerging Growth Company, as

defined in the Jumpstart Our Business Startups Act (or JOBS Act ), and are eligible to take advantage of certain exemptions from various reporting requirements that are applicable to other public companies that are not Emerging

Growth Companies. These include, but are not limited to, (i) reduced obligations with respect to the disclosure of selected financial data in registration statements filed with the Securities and Exchange Commission (including the

registration statement on Form 10 of which this information statement is a part), (ii) reduced disclosure obligations regarding executive compensation in our periodic reports and proxy statements, (iii) an exception from compliance with

the auditor attestation requirements of Section 404 of the Sarbanes-Oxley Act of 2002, and (iv) exemptions from the requirements of holding a nonbinding advisory vote on executive compensation and the requirement to obtain shareholder

approval of any golden parachute payments not previously approved.

In addition, Section 107 of the JOBS Act provides