resTORbio Reports Fourth Quarter and Full Year 2017 Financial Results

resTORbio Reports Fourth Quarter and Full Year

2017 Financial Results

Massachusetts, Mar. 29, 2018 resTORbio, Inc. (NASDAQ:TORC), a clinical-stage biopharmaceutical company focused on helping people live healthier longer through the development and commercialization of novel therapeutics for the

treatment of aging-related diseases, today reported financial results and provided a corporate update for the fourth quarter and full year ended December 31, 2017.

We recently completed our initial public offering, providing us the financial strength to pursue our goal of developing novel therapies for

aging-related diseases. We are evaluating the potential of TORC1 inhibition to improve these diseases, beginning with our ongoing Phase 2b study evaluating RTB101 as an immunotherapy to reduce the incidence of respiratory tract infections in the

elderly, said Chen Schor, President and CEO of resTORbio. In 2018, we look forward to reporting top-line data from this study in the second half of the year and to further developing RTB101, alone

or in combination with everolimus, for the treatment of additional aging-related diseases.

Recent Highlights and Outlook

Successfully Completed IPO: In January 2018, a successful initial public offering (IPO) was completed of 6,516,667 shares of common stock at a public

offering price of $15.00 per share, including the full exercise by the underwriters of their option to purchase additional shares. The net proceeds from the IPO were approximately $89.4 million after deducting underwriting discounts and

offering expenses. The proceeds will be used to evaluate the potential of RTB101 in multiple aging-related diseases.

Enrolling Ongoing Phase 2b

Study: In May 2017, a randomized, double-blind placebo-controlled Phase 2b trial was initiated to evaluate the safety, tolerability and efficacy of RTB101, an orally-administered, selective TORC1 inhibitor alone, or in combination with

everolimus, in reducing the incidence of respiratory tract infections (RTIs) in more than 600 elderly subjects. The Company is conducting the trial in two parts during the winter cold and flu seasons in both the southern and northern hemispheres.

The second part of the study commenced in the U.S. in the fourth quarter of 2017 following an interim analysis from the first part of the study conducted in New Zealand. Data from this trial are expected in the second half of 2018.

Data-Driven Approach to Expand into Additional Aging-Related Diseases: TORC1 inhibition may address multiple organ systems that fail or decline in

function with age, including the immune, cardiovascular and neurologic systems. The Company intends to leverage learnings from its ongoing Phase 2b trial, together with preclinical data, to further develop RTB101, alone or in combination with

everolimus, for the treatment of additional aging-related indications

where TORC1 inhibition may have therapeutic benefit. Within the ongoing Phase 2b trial, the incidence of urinary tract infections and a potential efficacy signal for heart failure will be

assessed as potential future indications. The Company plans to initiate at least one additional Phase 2 proof-of-concept study in an aging-related disease in 2018.

Fourth Quarter and Full Year 2017 Financial Results

resTORbio, Inc. is a clinical-stage

biopharmaceutical company focused on helping people live healthier longer through the development and commercialization of novel therapeutics for the treatment of aging-related diseases. resTORbio s lead program is targeting the selective

inhibition of TORC1 an evolutionary conserved pathway that contributes to the decline in function of multiple organ systems, including the immune, cardiac and neurologic systems. RTB101, resTORbio s lead drug candidate, is a selective,

orally administered, TORC1 inhibitor currently being tested in a Phase 2b clinical trial as a first in-class immunotherapy for reducing the incidence of respiratory tract infections in the elderly by enhancing

the function of the immune system. The company expects to develop RTB101 for additional aging-related indications such as heart failure or neurodegenerative diseases.

Forward Looking Statements

This press release contains forward-looking statements, which are made pursuant to the safe harbor provisions of Section 27A of the Securities Act of

1933, as amended, and Section 21E of the Securities Exchange Act of 1934, as amended. Investors are cautioned that statements in this press release which are not strictly historical statements, including, without limitation, express or implied

statements or guidance regarding our plans to develop and commercialize RTB101 alone or in combination with everolimus, including the therapeutic potential and clinical benefits thereof, our ongoing and future clinical trials for RTB101 alone or in

combination with everolimus, including the timing of initiation of these trials and of the anticipated results, constitute forward-looking statements identified by words like believe, expect, may,

will, should, seek, anticipate, or could and similar expressions. Such forward-looking statements are subject to a number of risks and uncertainties that could cause actual results to

differ materially from those anticipated, including, without limitation, risks associated with: the delay of any planned clinical trials and/or development of RTB101, either alone or in combination with everolimus; our ability to successfully

demonstrate the efficacy and safety of our lead product candidate; the clinical results for our lead product candidate which may not support further development of additional indications; and obtaining, maintaining and protecting our intellectual

property; as well as those risks more fully discussed in the section entitled Risk Factors in the final prospectus related to resTORbio s initial public offering filed with the Securities and Exchange Commission pursuant to Rule

424(b) of the Securities Act, as well as discussions of potential risks, uncertainties, and other important factors in resTORbio s subsequent filings with the Securities and Exchange Commission. In addition, any forward-looking statements

represent resTORbio s views only as of today and should not be relied upon as representing its views as of any subsequent date. resTORbio explicitly disclaims any obligation to update any forward-looking statements.

Stern Investor Relations, Inc.

CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS

thousands, except per share data)

CONDENSED CONSOLIDATED BALANCE SHEETS