PRTA INVESTORS ALERT: Lieff Cabraser Announces Securities Class Action Against Prothena Corporation plc

SAN FRANCISCO--()--The law firm of Lieff Cabraser Heimann & Bernstein, LLP announces that class action litigation has been filed on behalf of investors who purchased or otherwise acquired the publicly traded securities of Prothena Corporation plc (“Prothena” or the “Company”) (NYSE: PRTA) between October 15, 2015 and April 20, 2018, inclusive (the “Class Period”).

If you purchased or otherwise acquired Prothena’s publicly traded securities during the Class Period, you may move the Court for appointment as lead plaintiff by no later than July 16, 2018. A lead plaintiff is a representative party who acts on behalf of other class members in directing the litigation. Your share of any recovery in the actions will not be affected by your decision of whether to seek appointment as lead plaintiff. You may retain Lieff Cabraser, or other attorneys, as your counsel in the actions.

Prothena investors who wish to learn more about the litigation and how to seek appointment as lead plaintiff should click here or contact Sharon M. Lee of Lieff Cabraser toll-free at 1-800-541-7358.

Background on the Prothena Securities Class Litigation

Prothena, incorporated in Ireland and with U.S. headquarters in South San Francisco, California, is a development-stage biotechnology company.

The action alleges that Defendants made false and/or misleading statements and/or failed to disclose the results of an ongoing clinical trial for its principal drug, NEOD001, a monoclonal antibody used to treat a rare, debilitating disease that can lead to organ failure and death. According to the Complaint, throughout the Class Period Prothena cited the “best response” results from the Company’s ongoing clinical study of the NEOD001 antibody as evidence that the drug was effective, while withholding relevant trial data showing that the drug was not effective.

Plaintiff alleges that the truth began to emerge through a series of partial disclosures in 2017 and early 2018, culminating with the April 23, 2018 announcement that Prothena was ending all development of NEOD001 after data from the Phase 2b clinical trial showed that NEOD001 failed to reach either its primary or secondary endpoints, and was substantially less effective than the placebo. On this news, the Company’s share price fell 69%, or $25.34, from the previous closing price of $36.84 per share on April 20, 2018 to close at $11.50 per share on April 23, 2018, on extremely elevated trading volume.

About Lieff Cabraser

Lieff Cabraser Heimann & Bernstein, LLP, with offices in San Francisco, New York, Nashville, and Seattle, is a nationally recognized law firm committed to advancing the rights of investors and promoting corporate responsibility.

The National Law Journal has recognized Lieff Cabraser as one of the nation’s top plaintiffs’ law firms for 15 years. In compiling the list, the NLJ examines recent verdicts and settlements and looks for firms “representing the best qualities of the plaintiffs’ bar and that demonstrated unusual dedication and creativity.” Law360 selected Lieff Cabraser as one of the “Top 50 Law Firms Nationwide for Litigation,” highlighting our firm’s “laser focus” and noting that Lieff Cabraser routinely finds itself “facing off against some of the largest and strongest defense law firms in the world.” The publication separately named our firm one of five “2017 California Powerhouses,” the only plaintiffs' firm on the list. Best Lawyers and U.S. News named Lieff Cabraser as a “Law Firm of the Year” from 2012 through 2016, and the firm has received a number of other recent honors, awards, and recognition, including the National Law Journal’s “Elite Trial Lawyers,” Law360’s “Most Feared Plaintiffs’ Firms,” and Benchmark Litigation's “Top 10 Plaintiffs Firms in America.”

For more information about Lieff Cabraser and the firm’s representation of investors, please visit

This press release may be considered Attorney Advertising in some jurisdictions under the applicable law and ethical rules.


Lieff Cabraser Heimann & Bernstein, LLP
Sharon M. Lee, 1-800-541-7358

Release Summary

Lieff Cabraser announces securities class action was filed on behalf of investors of Prothena Corporation plc (NYSE: PRTA) between 5/15/15 & 4/20/18.


Lieff Cabraser Heimann & Bernstein, LLP
Sharon M. Lee, 1-800-541-7358