SHAREHOLDER ALERT: Levi & Korsinsky, LLP Notifies Shareholders of an Investigation Involving Possible Securities Fraud Violat...

Levi & Korsinsky, LLP announces that it has commenced an investigation of Proteostasis Therapeutics, Inc. (“Proteostasis Therapeutics” or the “Company”) (NASDAQ:PTI) concerning possible violations of federal securities laws by the Company and/or certain of its officers and directors.

On October 27, 2016, Proteostasis announced in a conference call that the results from its Phase 1 study of PTI-428 will be delayed to the first quarter of 2017. According to Proteostasis, the delay is due to the murder of a participant in the healthy volunteers trial and the resulting media attention, which slowed recruitment. The Company also cited Hurricane Matthew as an additional cause for the delay, as three trial sites were in the path of the storm. Following this news, shares of Proteostasis fell from a close of $12.85 per share on October 26, 2016, to a most recent close of $7.77 per share on October 28, 2016. To obtain additional information about the investigation, go to:

http://zlk.9nl.com/proteostasis-therapeutics-pti

or contact Joseph E. Levi, Esq. either via email at [e-mail] or by telephone at [phone], toll-free: [phone].

Levi & Korsinsky is a national firm with offices in New York, New Jersey, Connecticut and Washington D.C. The firm’s attorneys have extensive expertise in prosecuting securities litigation involving financial fraud, representing investors throughout the nation in securities and shareholder lawsuits. Attorney advertising. Prior results do not guarantee similar outcomes.

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Levi & Korsinsky, LLPJoseph E. Levi, Esq., 212-363-7500Toll Free: 877-363-5972Fax: [phone]www.zlk.com