Adaptive Biotechnologies : First Quarter Earnings Presentation

First Quarter 2021

Earnings Conference Call

Safe Harbor

This presentation has been prepared by Adaptive Biotechnologies Corporation ("we," "us," "our," "Adaptive" or the "Company") and is made for informational purposes only. The information set forth herein does not purport to be complete or to contain all relevant information. Statements contained herein are made as of the date of this presentation unless stated otherwise. This presentation shall not constitute an offer to sell or the solicitation of an offer to buy securities, nor shall there be any sale of these securities in any jurisdiction in which such offer, solicitation or sale would be unlawful prior to registration or qualification under the securities laws of any such jurisdiction.

This presentation contains "forward-looking statements" within the meaning of Section 27A of the Securities Act of 1933, as amended, and Section 21E of the Securities Exchange Act of 1934, as amended. These statements are intended to be covered by the "safe harbor" created by those sections. Forward-looking statements are neither historical facts nor assurances of future performance. Instead, they are based on our current beliefs, expectations and assumptions regarding the future of our business, future plans and strategies, our development plans, our preclinical and clinical results and other future conditions. In some cases, you can identify forward-looking statements by the following words: "may," "will," "could," "would," "should," "expect," "intend," "plan," "anticipate," "believe," "estimate," "predict," "project," "potential," "continue," "ongoing" or the negative of these terms or

other comparable terminology, although not all forward-looking statements contain these words. All statements, other than statements of historical facts, contained in this presentation are forward looking statements, including statements regarding the ability to map adaptive immune responses to target disease states, the ability to leverage any such findings to advance solutions to diagnose, treat and prevent infectious diseases; regarding our future financial or business performance, conditions, plans, prospects, trends or strategies and other financial and business matters; our current and prospective products and product candidates, including clonoSEQ, immunoSEQ and T-Detect products; discovery and development of neutralizing antibodies, FDA clearance or authorization of any products; planned non-IDE clinical studies, clinical trials and preclinical activities, research and development costs, current and prospective collaborations; the estimated size of the market for our products and product candidates; the timing and success of our development and commercialization of our anticipated product candidates; the availability of alternative therapies for our target markets; and the other risks and uncertainties described in our filings with the Securities and Exchange Commission including the Risk Factors and Management's Discussion and Analysis of Financial Condition and Results of Operations sections of our most recently filed Quarterly Reports on Form 10-Q and our Annual Report on Form 10-K, including our most recent Annual Report on Form 10-K filed on February 24, 2021. Although we believe the expectations reflected in such forward-looking statements are reasonable, we can give no assurance that such expectations will prove to be correct. Risks and uncertainties could cause actual results to differ materially from those expressed in our forward-looking statements. Accordingly, readers are cautioned not to place undue reliance on these forward-looking statements. Except as required by applicable law, we do not plan to publicly update or revise any forward-looking statements contained herein.

Certain information contained in this presentation relates to or is based on studies, publications, surveys and other data obtained from third-party sources and the Company's own internal estimates and research. While the Company believes these third-party sources to be reliable as of the date of this presentation, it has not independently verified, and makes no representation as to the adequacy, fairness, accuracy or completeness of, any information obtained from third-party sources. In addition, all of the market data included in this presentation involves a number of assumptions and limitations, and there can be no guarantee as to the accuracy or reliability of such assumptions. Finally, while we believe our own internal research is reliable, such research has not been verified by any independent source.

2

Q1 2021 Key Highlights

• .T-DetectCOVID: granted EUA by the FDA to confirm COVID-19 past infection
• • .T-DetectGI: Crohn's data results confirm signal and show distinction from colitis
  • .MRD pharma portfolio: monetized 2 milestones; added Pfizer MRD partnership

Strong Revenues

Q1'21 $38.4M✓ .immunoSEQ T-MAPCOVID: uptake by more pharma and academic partners

(+84% y/y)

(+27% q/q)

• • .Cell Therapy: private product initial proof of concept in 15 cancer patients delivered to GNE
• .Strong balance sheet: ending cash, cash equivalents and marketable securities of $745M

3

T-Detect Franchise, COVID sets the stage for future indications

CLINICAL DIAGNOSTICS

T-Detect COVID available

• Granted EUA by FDA to confirm SARS-CoV-2 past infection
• >3,000 tests ordered since launch
• >50 concierge medicine groups ordering the test
• ~75% latest opt-in rate for ongoing research to understand immunity

Confirm recent or past

COVID-19 infection

Strategic value for franchise

• R&D acceleration
• • FDA authorized 1st T-cell test
  • Validation of T-cell based assay
  • Clinical study execution
  • New models & techniques to utilize
• Commercial development
• • Built brand to scale to additional indications
  • Awareness for Adaptive & T-Detect
  • Built base commercial infrastructure

4

T-Detect: building towards the future

Accelerating

Differential Diagnostic

approach

1

2

3

Improve SOC Dx

Disease by disease

T-Detect	T-Detect
COVID	Lyme
◼ Launched 1 yr	◼ 2nd potential
early	indication
◼ Validated platform	◼ CLIA launch EOY
◼ EUA cleared	◼ ImmuneSense to
	be completed
	EOY

Differential Diagnosis

Diseases with shared symptoms

T-Detect GI

• Proof of concept validated
• Greater value proposition
• Evaluating alternatives to expedite validation of differential diagnosis among patients with shared symptoms

Population Immunomics

Any mapped disease

Aspirational long-term

vision

• One blood test with many results

5