Investor Contact: Chris Lowe Cortexyme, Inc. Chief Financial Officer clowe@cortexyme.com Media Contact: Hal Mackins For Cortexyme, Inc. hal@torchcomllc.com (415) 994-0040 Cortexyme Announces First Quarter 2020 Financial

Cortexyme Announces First Quarter 2020 Financial Results and Provides Business Update

Interim analysis for the GAIN Trial on track for Q4 2020, with top-line results from

analysis expected in Q4 2021

Cortexyme shared additional scientific evidence supporting the gingipain hypothesis via multiple

presentations and publications

SAN FRANCISCO, Calif. May 12, 2020 Cortexyme, Inc. (Nasdaq: CRTX), a clinical stage biopharmaceutical company pioneering potential therapeutics for Alzheimer s and other degenerative diseases, today announced

financial results for the first quarter 2020 and provided an update on its business.

The current global environment is challenging on many levels,

but Cortexyme continues to execute and progress toward our goal of developing a novel treatment to halt progression of Alzheimer s disease, said Casey Lynch, Cortexyme s chief executive officer,

co-founder, and chair. We remain highly focused on the execution of the GAIN Trial, which is currently on track to complete enrollment of 570 patients this year and for which top-line results are anticipated in the fourth quarter of 2021. At the same time, we continue to research and publish new data that sheds light on the potential clinical utility of gingipain inhibitors for treatment

of Alzheimer s and other diseases. With a strong balance sheet and a talented team, we re committed to creating value for all of our stakeholders, especially the neurodegenerative disease patients and caregivers in need of new therapeutic

Scientific Updates: Advancing a New Understanding of Alzheimer s Causation and Treatment

As COR388 moves through late-stage clinical development, Cortexyme and external collaborators continue to present and publish new research to advance

understanding of the gingipain hypothesis for Alzheimer s pathogenesis and the clinical potential of COR388. Recent scientific presentations and publications are as follows:

Financial Results for the Quarter Ended March 31, 2020

Cash, Cash Equivalents and Marketable Securities: Cash, cash equivalents, and short and long-term marketable securities as of

March 31, 2020, were $223.5 million, and includes approximately $117.7 million of net proceeds raised in Cortexyme s successful private placement offering completed in February 2020. Cortexyme expects current cash, cash

equivalents and marketable securities will be sufficient to fund its operating and capital expenditures through 2022 and the completion of the GAIN Trial.

Research and Development (R&D) Expenses: For the quarter ended March 31, 2020, R&D expenses were $14.4 million. The expense

was primarily due to costs related to the research and development of COR388 and the GAIN Trial.

General and Administrative (G&A)

Expenses: For the quarter ended March 31, 2020, G&A expenses were $3.5 million. The expense was primarily attributable to personnel-related expenses, insurance, professional and legal fees, and stock-based compensation.

Net Loss: For the quarter ended March 31, 2020, net loss was $17.2 million, or a loss of $0.61 per basic share.

About Cortexyme, Inc.

Cortexyme (Nasdaq: CRTX) is a clinical stage biopharmaceutical company pioneering a novel, disease-modifying therapeutic approach to treat what it

believes to be a key underlying cause of Alzheimer s disease and other degenerative diseases. Cortexyme is targeting a specific, infectious pathogen found in the brain of Alzheimer s patients and tied to neurodegeneration and

neuroinflammation in animal models. Cortexyme s lead investigational medicine, COR388, is the subject of the GAIN Trial, an ongoing Phase 2/3 clinical study in patients with mild to moderate Alzheimer s disease. To learn more

about Cortexyme, visit www.cortexyme.com or follow @Cortexyme on Twitter.

Forward-Looking Statements

Statements in this press release contain forward-looking statements that are subject to substantial risks and uncertainties. Forward-looking

statements contained in this press release may be identified by the use of words such as anticipate, expect, believe, will, may, should, estimate,

project, outlook, forecast or other similar words. Examples of forward-looking statements include, among others, statements we make regarding our business plans and prospects, cash forecasts, the timing and

success of our clinical trials and related data, ability to fund planned operating and capital expenditures, the timing of announcements and updates relating to our clinical trials and related data, the timing of and our ability to enroll patients

into our clinical trials, and the potential therapeutic benefits, safety and efficacy of our product candidate or library of compounds. Forward-looking statements are based on Cortexyme s current expectations and are subject to inherent

uncertainties, risks and assumptions that are difficult to predict and could cause actual results to differ materially from what we expect. Further, certain forward-looking statements are based on assumptions as to future events that may not prove

be accurate. Factors that could cause actual results to differ include, but are not limited to, the risks and uncertainties described in the section titled Risk Factors in our Annual

Report on Form 10-K filed with the Securities and Exchange Commission (SEC) on March 16, 2020, our Quarterly Report on Form 10-Q filed with the SEC on

May 12, 2020, and other reports as filed with the SEC. Forward-looking statements contained in this press release are made as of this date, and Cortexyme undertakes no duty to update such information except as required under

see attached financial tables

Cortexyme, Inc. Condensed Statements of Operations

(In thousands, except per share amounts)

Cortexyme, Inc. Condensed Balance Sheets

(In thousands, per share amounts)