Iterum Therapeutics Reports First Quarter 2019 Financial Results On track to complete enrollment in all three Phase 3 clinical trials before year-end Filed patent application that may extend Iterum'

Iterum Therapeutics Reports First Quarter 2019 Financial Results

On track to complete enrollment in all three Phase 3 clinical trials before year-end

Filed patent application that may extend Iterum's intellectual property rights into the 2040s

DUBLIN, Ireland and CHICAGO, May 14, 2019 -- Iterum Therapeutics plc (Nasdaq: ITRM), a clinical-stage pharmaceutical company developing anti-infectives against multi-drug resistant pathogens, today reported financial results for the first quarter ended March 31, 2019.

"The first quarter of 2019 was highlighted by the U.S. Food and Drug Administration (FDA) granting us Qualified Infectious Disease Product (QIDP) status in four new indications, as well as Fast Track designation for all seven potential indications of oral and IV sulopenem for which QIDP status has been received," said Corey Fishman, Chief Executive Officer of Iterum Therapeutics plc. "We remain focused on completing enrollment of all three of our ongoing Phase 3 clinical trials this year. A new effective oral therapy in our studied indications has become critical due to the rise in multi-drug resistant infections in the community, and we are excited to be at the forefront of seeking to provide a near-term solution."

Q1 2019 Highlights and Recent Events

Upcoming Scientific and Investor Presentations

First Quarter 2019 Financial Results

As of March 31, 2019, Iterum had cash, cash equivalents and short-term investments of $69.6 million and approximately 14.4 million shares outstanding. Iterum expects that its cash, cash equivalents and short-term investments, along with its available borrowings, will be sufficient to fund operations into 2020.

Research and development (R&D) expenses for the first quarter of 2019 were $17.4 million compared to $10.9 million for the same period in 2018. The increase was primarily due to higher clinical trial expenses associated with the three Phase 3 clinical trials initiated in the third quarter of 2018.

General and administrative (G&A) expenses for the first quarter of 2019 were $3.1 million compared to $1.5 million for the same period in 2018. The increase was primarily due to increased costs associated with operating as a public company, additional headcount to support business activities, and increased marketing and market research expenses.

For the first quarter of 2019, Iterum reported a net loss of $20.6 million compared to a net loss of $12.1 million for the same period in 2018.

Sulopenem, a novel penem anti-infective compound with oral and IV formulations, has demonstrated potent in vitro activity against a wide variety of gram-negative, gram-positive and anaerobic bacteria resistant to other antibiotics. If approved, sulopenem will help address the significant clinical and economic need for new oral antibiotics that enable the effective treatment of resistant pathogens in the community, make possible the avoidance of hospitalization, and facilitate early hospital discharge by providing continuity-of-care step-down therapy. The safety

profile of IV sulopenem has been documented in a Phase 2 program. Oral and IV sulopenem are being evaluated in three pivotal Phase 3 clinical trials for uncomplicated urinary tract infections, complicated urinary tract infections, and complicated intra-abdominal infections.

Probenecid, which is being co-administered with sulopenem in a bilayer tablet, is approved as an adjuvant to therapy for elevation and prolongation of plasma levels of -lactam compounds including penicillin, ampicillin, methicillin, oxacillin, cloxacillin, and nafcillin.

About Iterum Therapeutics plc

Iterum Therapeutics plc is a clinical-stage pharmaceutical company dedicated to developing differentiated anti-infectives aimed at combatting the global crisis of multi-drug resistant pathogens to significantly improve the lives of people affected by serious and life-threatening diseases around the world. Iterum Therapeutics is advancing its first compound, sulopenem, a novel penem anti-infective compound, in Phase 3 clinical development with oral and IV formulations. Sulopenem has demonstrated potent in vitro activity against a wide variety of gram-negative, gram-positive and anaerobic bacteria resistant to other antibiotics. Iterum Therapeutics has received QIDP and Fast Track designations for its oral and IV formulations of sulopenem in seven indications. For more information, please visit http://www.iterumtx.com.

Forward Looking Statements

This press release contains forward-looking statements. These forward-looking statements include, without limitation, statements regarding expectations about future revenue, expenses, cash flows and net income or loss, the sufficiency of cash resources, the granting or issuing of patents, the development, therapeutic and market potential of sulopenem, and the timing, progress and results of clinical trials. In some cases, forward-looking statements can be identified by words such as "may," "believes," "intends," "seeks," "anticipates," "plans," "estimates," "expects," "should," "assumes," "continues," "could," "will," "future," "potential" or the negative of these or similar terms and phrases. Forward-looking statements involve known and unknown risks, uncertainties and other factors that may cause Iterum Therapeutics' actual results, performance or achievements to be materially different from any future results, performance or achievements expressed or implied by the forward-looking statements. Forward-looking statements include all matters that are not historical facts. Actual future results may be materially different from what is expected due to factors largely outside Iterum Therapeutics' control, including the uncertainties inherent in the initiation and conduct of clinical trials, clinical trial patient enrollment, availability and timing of data from clinical trials, changes in regulatory requirements or decisions of regulatory authorities, commercialization plans and timelines, if approved, the actions of third-party clinical research organizations, suppliers and manufacturers and other factors discussed under the caption "Risk Factors" in its Quarterly Report on Form 10-Q filed with the Securities and Exchange Commission (the "SEC") on May 14, 2019, and other documents filed with the SEC from time to time. Forward-looking statements represent Iterum Therapeutics' beliefs and assumptions only as of the date of this press release. Except as required by law, Iterum Therapeutics assumes no obligation to update these forward-looking statements publicly, or to update the reasons actual results could differ materially from those anticipated in the forward-looking statements, even if new information becomes available in the future.

Chief Financial Officer

ITERUM THERAPEUTICS PLC

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ITERUM THERAPEUTICS PLC

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