February 8, 2016
Securities and Exchange Commission
Division of Corporation Finance
100 F Street, N.E.
Washington, D.C. 20549
| Re: | Proteostasis Therapeutics, Inc. |
Registration Statement on Form S-1 (SEC File No. 333-208735)
Ladies and Gentlemen:
In connection with the above-referenced Registration Statement, and pursuant to Rule 461 under the Securities Act of 1933, as amended (the “Act”), we hereby join in the request of Proteostasis Therapeutics, Inc. that the effective date of the Registration Statement be accelerated so that it will be declared effective at 4:30 p.m., Eastern time, on February 10, 2016 or as soon thereafter as practicable.
Pursuant to Rule 460 under the Act, please be advised that we have distributed approximately 1120 copies of the Preliminary Prospectus dated February 1, 2016 (the “Preliminary Prospectus”) through the date hereof, to underwriters, dealers, institutions and others.
In connection with the Preliminary Prospectus distribution for the above-referenced issue, the prospective underwriters have confirmed that they are complying with the 48-hour requirement as promulgated by Rule15c2-8 under the Securities Exchange Act of 1934, as amended.
[Remainder of page intentionally left blank]
Very truly yours,
LEERINK PARTNERS LLC
RBC CAPITAL MARKETS, LLC
As Representatives
| By: | LEERINK PARTNERS LLC | |
| By: | /s/ John I. Fitzgerald, Esq. | |
| Name: John I. Fitzgerald, Esq. | ||
| Title: Managing Director | ||
| By: | RBC CAPITAL MARKETS, LLC | |
| By: | /s/ Orestes Tarajano | |
| Name: Orestes Tarajano | ||
| Title: Managing Director | ||
[Signature Page to Acceleration Request]