Summary of PROTHENA CORP PLC

Item 5.02 Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers.

On March 4, 2013, the Compensation Committee of the Board of Directors of Prothena Corporation plc ("Parent") approved and adopted certain key terms of severance and change in control policies (the "Severance Policies") for Prothena Biosciences Inc, an indirect wholly-owned subsidiary of Parent (the "Company") under which eligible employees of the Company, including (i) employees hired after the adoption of the Severance Policies and (ii) beginning on January 1, 2014, employees of the Company previously employed by Elan Corporation, plc ("Elan") and employed by the Company in connection with the spin-off of Parent's business from Elan, are entitled to certain severance and change in control benefits, including the following:

Termination Not in Connection With a Change in Control

Lump Sum Cash Payments Not in Connection With a Change in Control. In the event
of a qualifying termination that occurs outside of the 24 month period
commencing on the consummation of a change in control (as shall be defined in
the Severance Policies), the Company will pay the following lump sum cash
payments:



                 Title                                     Amount
Chief Executive Officer (Dr. Dale          (i) 150% of the employee's annual base
Schenk)                                    salary as of the date of termination
                                           (ii) 100% of the employee's annual
                                           target bonus
Leadership I (includes Dr. Gene Kinney,    (i) 100% of the employee's annual base
Chief Scientific Officer and Head of       salary as of the date of termination
Research and Development)                  (ii) 100% of the employee's annual
                                           target bonus
Leadership II (includes Dr. Tara           100% of the employee's annual base
Nickerson, Head of Corporate and           salary as of the date of termination
Business Development)
Management (includes John Randall          The greater of (i) 50% of the
Fawcett, Controller)                       employee's annual base salary as of
                                           the date of termination or (ii) two
                                           weeks' portion of the employee's
                                           annual base salary as of the date of
                                           termination for each year of service
                                           to the Company, subject to a cap of
                                           100% of the employee's annual base
                                           salary as of the date of termination

Acceleration of Equity Vesting Not in Connection With a Change in Control. In the event of a qualifying termination that occurs outside of the 24 month period commencing on the consummation of a change in control, each outstanding equity award held by a terminated employee shall accelerate in vesting as follows:

                 Title                                  Acceleration
Chief Executive Officer (Dr. Dale          That number of shares that would have
Schenk)                                    vested had such employee continued
                                           employment for the 18 month period
                                           immediately following the date of
                                           termination.
Leadership I (includes Dr. Gene Kinney,    That number of shares that would have
Chief Scientific Officer and Head of       vested had such employee continued
Research and Development)                  employment for the 12 month period
                                           immediately following the date of
                                           termination.
Leadership II (includes Dr. Tara
Nickerson, Head of Corporate and
Business Development)
Management (includes John Randall          None.
Fawcett, Controller)

Termination in Connection With a Change in Control

Lump Sum Cash Payments in Connection With a Change in Control. In the event of a
qualifying termination that occurs within the 24 month period commencing on the
consummation of a change in control, the Company will pay the following lump sum
cash payments:



                 Title                                     Amount
Chief Executive Officer (Dr. Dale          (i) 250% of the employee's annual base
Schenk)                                    salary as of the date of termination
                                           (ii) 250% of the employee's annual
                                           target bonus
Leadership I (includes Dr. Gene Kinney,    (i) 150% of the employee's annual base
Chief Scientific Officer and Head of       salary as of the date of termination
Research and Development)                  (ii) 150% of the employee's annual
                                           target bonus
Leadership II (includes Dr. Tara           150% of the employee's annual base
Nickerson, Head of Corporate and           salary as of the date of termination
Business Development)
Management (includes John Randall          Same as the lump sum cash payment not
Fawcett, Controller)                       in connection with a change in
                                           control.

Acceleration of Equity Vesting in Connection With a Change in Control. In the event of a qualifying termination that occurs within the 24 month period commencing on the consummation of a change in control, each outstanding equity award held by a terminated employee shall accelerate in vesting as follows:

                 Title                                  Acceleration
Chief Executive Officer (Dr. Dale
Schenk)
Leadership I (includes Dr. Gene Kinney,
Chief Scientific Officer and Head of
Research and Development)
Leadership II (includes Dr. Tara                100% of then unvested shares
Nickerson, Head of Corporate and
Business Development)
Management (includes John Randall
Fawcett, Controller)

Additional Severance Benefits

Benefits Continuation. In the event of a qualifying termination, terminated employees shall be entitled, at their election, to receive continued healthcare coverage pursuant to the Consolidated Omnibus Budget Reconciliation Act of 1985, as amended ("COBRA"), for which the Company will directly pay, or reimburse for, the portion of the COBRA premiums for such terminated employees and their covered dependents that exceeds the amount of such premium an active employee would be required to pay during the period commencing on the termination of employment and ending upon the earliest of (X) the applicable period set forth below, (Y) the date that a terminated employee and/or their covered dependents, as applicable, become no longer eligible for COBRA or (Z) the date a terminated employee becomes eligible to receive healthcare coverage from a subsequent employer:

                 Title                             Benefits Continuation
Chief Executive Officer (Dr. Dale          The 18 month anniversary of the date
Schenk)                                    of termination.
Leadership I (includes Dr. Gene Kinney,
Chief Scientific Officer and Head of       The 12 month anniversary of the date
Research and Development)                  of termination.
Leadership II (includes Dr. Tara
Nickerson, Head of Corporate and
Business Development)
Management (includes John Randall          The six month anniversary of the date
Fawcett, Controller)                       of termination.

Career Transition Assistance. In the event of a qualifying termination, terminated employees commencing a career transition assistance program sponsored or arranged for by the Company within 60 days following the date of termination shall be entitled to the Company paying for such program for the applicable period set forth below:

                 Title                                 Career Transition
Chief Executive Officer (Dr. Dale
Schenk)
Leadership I (includes Dr. Gene Kinney,
Chief Scientific Officer and Head of       12 months from the date of termination.
Research and Development)
Leadership II (includes Dr. Tara
Nickerson, Head of Corporate and
Business Development)
Management (includes John Randall
Fawcett, Controller)                       Nine months from the date of termination.

The foregoing terms of the Severance Policies do not modify the benefits provided to Dr. Dale Schenk, President and Chief Executive Officer of the Company, pursuant to Dr. Schenk's employment agreement with the Company, as disclosed in Parent's Current Report on Form 8-K filed with the SEC on January 25, 2013, except that a qualifying termination that occurs within the 24 month period commencing on the consummation of a change in control, rather than the 12 month period provided for in Dr. Schenk's agreement, shall be considered a termination in connection with a change in control. Except for such 24 month period with respect to Dr. Schenk, the foregoing terms will not take effect with respect to the officers named herein until January 1, 2014, pursuant to the terms of the Severance Policies.

The preceding description of the Severance Policies is intended only as a summary and is qualified in its entirety by reference to the full terms of such policies, which shall be filed as exhibits to Parent's Annual Report on Form 10-K for the year ended December 31, 2012.