Equillium Reports Fourth Quarter and Full Year 2022 Financial Results and Provides Corporate & Clinical Development Updates $71.0 million cash balance at the end of 2022 expected to provide cash runway into 2025 Acquired

Equillium Reports Fourth Quarter and Full Year 2022 Financial Results and

Provides Corporate & Clinical Development Updates

$71.0 million cash balance at the end of 2022 expected to provide cash runway into 2025

Acquired Bioniz Therapeutics, including two first-in-class

clinical-stage assets, EQ101 and EQ102, and proprietary product discovery platform

Initiated Phase 2 clinical study of EQ101 in alopecia

areata and first-in-human clinical study of EQ102

into strategic partnership and an option and asset purchase agreement with Ono Pharmaceutical for the development and commercialization rights to itolizumab, including an upfront payment of $26.4 million, development funding, and approximately

$139 million1 in potential option exercise and milestone payments

LA JOLLA, California,

March 23, 2023 Equillium, Inc. (Nasdaq: EQ), a clinical-stage biotechnology company leveraging a deep understanding of immunobiology to develop novel therapeutics to treat severe autoimmune and inflammatory disorders

with high unmet medical need, today announced financial results for the fourth quarter and full year 2022 and provided corporate and clinical development updates.

Equillium achieved several significant objectives during 2022, and in the process transformed into a company with a newly diversified pipeline including two

wholly-owned, first-in-class clinical-stage assets, a proprietary drug discovery platform and a strong balance sheet expected to fund our development programs through

multiple key milestones, said Bruce Steel, chief executive officer at Equillium. We acquired Bioniz Therapeutics in February last year expanding our pipeline with two multi-cytokine inhibitors, EQ101 and EQ102, that we have since

advanced into a Phase 2 clinical study in subjects with alopecia areata and a first-in-human clinical study in healthy volunteers to be followed by patients with celiac

disease, respectively. We plan to announce data from both studies in the second half of this year. Based on the initiation of EQUATOR, our pivotal study of itolizumab in first-line acute graft-versus-host disease, and positive interim data from the

EQUALISE study of itolizumab in patients with lupus nephritis, we secured a strategic partnership with Ono Pharmaceutical under which they purchased an exclusive option to acquire our rights for the development and commercialization of itolizumab.

The partnership came with payments to Equillium totaling $38.6 million during December 2022, funding of itolizumab research and development costs during the option period, and potential future option exercise and milestone payments totaling

approximately $139 million1. Based on our strong cash balance and significantly reduced operating burn resulting from the Ono partnership, we expect to be able to fund operations into 2025, and

potentially beyond if Ono exercises its option. We look forward to upcoming data from the EQ101 and EQ102 development programs and continuing to advance itolizumab under our Ono partnership.

2022 Corporate Highlights:

2022 Clinical Highlights:

Anticipated Upcoming Milestones:

Fourth Quarter and Full Year 2022 Financial Results

Revenue for the fourth quarter and full year of 2022 was $15.8 million and was derived from the company s asset purchase agreement with Ono.

There was no revenue recognized in the year ended December 31, 2021.

Research and development (R&D) expenses for the fourth quarter of

2022 were $8.5 million, compared with $7.5 million for the same period in 2021. For the full year of 2022, R&D expenses were $37.5 million, compared with $26.4 million for the full year of 2021. The year-over-year increase in

R&D expenses was driven by start-up costs related to our Phase 3 EQUATOR clinical study and to a lesser extent start-up costs related to our EQ101 and EQ102 clinical

studies, an increase in non-clinical research expenses and employee compensation and benefits, offset by a greater estimated Australian R&D Tax Incentive benefit and lower costs associated with our other

itolizumab clinical studies.

General and administrative (G&A) expenses for the fourth quarter of 2022 were $5.2 million, compared with

$2.8 million for the same period in 2021. For the full year of 2022, G&A expenses were $17.2 million, compared with $11.4 million for the full year of 2021. The year-over-year increase was primarily driven by increased legal

expenses related to business development activities, greater headcount and consulting expenses, the non-cash write-off of issuance costs related to certain financings

where future proceeds were unlikely, and greater overhead expenses.

Net Income for the fourth quarter of 2022 was $2.8 million, or $0.08 per basic share and diluted

share, compared with a net loss of $10.6 million, or $(0.36) per basic and diluted share for the same period in 2021. Net loss for the full year of 2022 was $62.4 million, or $(1.85) per basic and diluted share, compared with a net loss of

$39.1 million, or $(1.36) per basic and diluted share for the full year of 2021. The increase in net loss for the full year of 2022 compared to the full year of 2021 was driven primarily by greater operating expenses, including a non-cash in-process R&D expense related to the acquisition of Bioniz in 2022, partially offset by revenue recognized in the fourth quarter of 2022 related to the Ono

Cash, cash equivalents and short-term investments totaled $71.0 million as of December 31, 2022, compared to

$80.7 million as of December 31, 2021. Cash provided by operating activities in the fourth quarter of 2022 was $27.7 million. Non-GAAP Adjusted Cash Used in Operations in the fourth quarter of

2022 was $5.2 million, which excludes the one-time upfront payment from Ono and is further adjusted by incorporating only the development funding received from Ono pertaining to itolizumab development

costs in the fourth quarter of 2022. Equillium believes that its cash, cash equivalents and short-term investments will be sufficient to fund its currently planned operations into 2025.

Use of Non-GAAP Financial Measures (Unaudited)

In this release, we use the metric of Adjusted Cash Used in Operations, which is a non-GAAP financial measure and is not

calculated in accordance with generally accepted accounting principles in the United States (GAAP). Adjusted Cash Used in Operations reflects adjustments to net cash provided by (used in) operating activities to exclude the effects of any one-time payments from Ono and quarterly development funding received in but unrelated to the period, and add any quarterly development funding amounts receivable related to development costs in the period.

We believe Adjusted Cash Used in Operations is a useful metric to investors as a supplement to GAAP measures in the assessment of our operating cash burn because it

removes the effects of any one-time payments, which are not indicative of our ongoing cash flow from operations, and it provides better matching of the timing of itolizumab development funding payments with

the associated itolizumab development costs. However, Adjusted Cash Used in Operations may fluctuate significantly from quarter to quarter, and the estimate provided for one quarter should not be assumed to be representative of other quarters. In

addition, this non-GAAP financial measure may be different from non-GAAP financial measures used by other companies, even when the same or similarly titled terms are

used to identify such measures, limiting their usefulness for comparative purposes.

This non-GAAP financial measure is

not meant to be considered in isolation or used as a substitute for net cash provided by (used in) operating activities reported in accordance with GAAP; should be considered in conjunction with our financial information presented in accordance with

GAAP; has no standardized meaning prescribed by GAAP; is unaudited; and is not prepared under any comprehensive set of accounting rules or principles. In addition, from time to time in the future, there may be other items that we may exclude for

purposes of this non-GAAP financial measure, and we may in the future cease to exclude items that we have historically excluded for purposes of this non-GAAP financial

measure. Likewise, we may determine to modify the nature of adjustments to arrive at this non-GAAP financial measure. Because of the non-standardized definitions of non-GAAP financial measures, the non-GAAP financial measure as used by us in this press release and the accompanying reconciliation table has limits in its usefulness to

investors and may be calculated differently from, and therefore may not be directly comparable to, similarly titled measures used by other companies. Accordingly, investors should not place undue reliance on

non-GAAP financial measures. Reconciliations of this non-GAAP financial measure to the most directly comparable GAAP financial measure are presented in the table at the

end of this release.

About Multi-Cytokine Platform and EQ101 & EQ102

Our proprietary multi-cytokine platform generates rationally designed composite peptides that selectively block key

cytokines at the shared receptor level targeting pathogenic cytokine redundancies and synergies while preserving non-pathogenic signaling. This approach is expected to avoid the broad immuno-suppression and off-target safety liabilities that may be associated with other therapeutic classes, such as Janus kinase inhibitors. Many immune-mediated diseases are driven by the same combination of dysregulated cytokines, and

we believe identifying the key cytokines for these diseases will allow us to target and develop customized treatment strategies for multiple autoimmune and inflammatory diseases.

Current platform assets include EQ101, a first-in-class, selective, tri-specific inhibitor of IL-2, IL-9 and IL-15, and EQ102, a first-in-class, selective, bi-specific inhibitor of IL-15 and IL-21.

Itolizumab is a clinical-stage, first-in-class anti-CD6 monoclonal antibody that selectively targets the CD6-ALCAM signaling

pathway to selectively downregulate pathogenic T effector cells while preserving T regulatory cells critical for maintaining a balanced immune response. This pathway plays a central role in modulating the activity and trafficking of T cells that

drive a number of immuno-inflammatory diseases.

Equillium is a clinical-stage biotechnology company leveraging a deep understanding of immunobiology to develop novel therapeutics to treat severe autoimmune and

inflammatory disorders with high unmet medical need. The company s pipeline consists of the following novel first-in-class immunomodulatory assets targeting

immuno-inflammatory pathways. EQ101: a tri-specific cytokine inhibitor that selectively targets IL-2, IL-9, and IL-15; currently under evaluation in a Phase 2 proof-of-concept clinical study of patients with alopecia areata. EQ102: a bi-specific cytokine inhibitor that selectively targets IL-15 and IL-21; currently under evaluation in a Phase 1 first-in-human clinical study to include healthy volunteers and celiac disease patients. Itolizumab: a monoclonal antibody that targets the

CD6-ALCAM signaling pathway which plays a central role in the modulation of effector T cells; currently under evaluation in a Phase 3 clinical study of patients with acute graft-versus-host disease (aGVHD) and

a Phase 1b clinical study of patients with lupus/lupus nephritis. Equillium acquired rights to itolizumab through an exclusive partnership with Biocon Limited and has entered a strategic partnership with Ono Pharmaceutical Co., Ltd. for the

development and commercialization of itolizumab under an option and asset purchase agreement.

For more information, visit www.equilliumbio.com.

Forward Looking Statements

Statements contained in this press release

regarding matters that are not historical facts are forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995. Forward-looking statements may be identified by the use of words such as

anticipate , believe , could , continue , expect , estimate , may , plan , outlook , future and project and other similar

expressions that predict or indicate future events or trends or that are not statements of historical matters. Because such statements are subject to risks and uncertainties, many of which are outside of Equillium s control, actual results may

differ materially from those expressed or implied by such forward-looking statements. Such statements include, but are not limited to, statements regarding Equillium s plans and expected timing for developing EQ101 and EQ102 including the

expected timing of initiating, completing and announcing further results from Phase 2 and Phase 1 clinical studies, respectively, the potential for any of Equillium s ongoing or planned clinical studies to show safety or efficacy, the benefit

of treating patients with aGVHD or lupus/lupus nephritis with itolizumab, Equillium s plans and expected timing for developing itolizumab including the expected timing of initiating, completing and announcing further results from the EQUATE,

EQUATOR and EQUALISE studies, Equillium s anticipated timing of regulatory review and feedback, the potential benefits and risks of the transactions contemplated by the asset purchase agreement entered into between Equillium and Ono, including

the possibility that Ono does not exercise the

option, Equillium receives no further payments under the asset purchase agreement other than those already received, the fluctuation of the foreign exchange rate, Equillium s cash runway,

and Equillium s plans and expected timing for developing its product candidates and potential benefits of its product candidates. Risks that contribute to the uncertain nature of the forward-looking statements include: Equillium s ability

to execute its plans and strategies; risks related to performing clinical studies; the risk that interim results of a clinical study do not necessarily predict final results and that one or more of the clinical outcomes may materially change as

patient enrollment continues, following more comprehensive reviews of the data, and as more patient data become available; potential delays in the commencement, enrollment and completion of clinical studies and the reporting of data

therefrom; the risk that studies will not be completed as planned; Equillium s plans and product development, including the initiation and completion of clinical studies and the reporting of data therefrom; whether the

results from clinical studies will validate and support the safety and efficacy of Equillium s product candidates; risks related to Ono s financial condition, willingness to continue to fund the development of itolizumab, and decision to

exercise its option to purchase itolizumab or terminate the asset purchase agreement; changes in the competitive landscape; uncertainties related to Equillium s capital requirements; and having to use cash in ways or on timing other than

expected and the impact of market volatility on cash reserves. These and other risks and uncertainties are described more fully under the caption Risk Factors and elsewhere in Equillium s filings and reports, which may be accessed

for free by visiting the Securities and Exchange Commission s website at and on Equillium s website under the heading Investors. Investors should take such risks into account and should not rely on forward-looking statements

when making investment decisions. All forward-looking statements contained in this press release speak only as of the date on which they were made. Equillium undertakes no obligation to update such statements to reflect events that occur or

circumstances that exist after the date on which they were made, except as required by law.

Investor & Media Contact

Vice President, Investor Relations Officer & Head of Corporate Communications

Condensed Consolidated Balance Sheets

Condensed Consolidated Statements of Operations