EXAGEN INC

There have been no material changes to the risk factors disclosed in Part I, Item 1A, "Risk Factors" of our Annual Report on Form 10-K for the year ended December 31, 2023, other than those set forth below:

We may become subject to extensive regulatory requirements and may be required to conduct additional clinical trials prior to continuing to sell our existing tests or launching any other tests we may develop, which may increase the cost of conducting, or otherwise harm, our business.

We currently market our AVISE® tests as laboratory developed tests (LDTs) and may, in the future, market other tests as LDTs. Although historically the Food and Drug Administration (FDA) has applied a policy of enforcement discretion with respect to LDTs whereby the FDA does not generally actively enforce its regulatory requirements for such tests, in October 2023, the FDA issued a proposed rule to regulate LDTs under the current medical device framework. The agency’s final rule was released to the public on April 29, 2024 and will be officially published in the Federal Register on May 6, 2024, with an effective date of July 5, 2024. The agency’s final rule provides that the LDT enforcement policy phase-out process will occur in gradual stages over a total period of four years, with pre-market approval applications for high-risk tests to be submitted by the 3.5-year mark. Moderate-risk and low-risks tests are expected to be in compliance at the 4-year mark, although the FDA has stated that if premarket submissions are pending review it will continue to exercise enforcement discretion with respect to those tests. The FDA’s final rule is complex and, concurrently, the agency announced several exceptions from the requirement to comply with full medical device regulatory controls, depending upon the specific nature of the LDT and the clinical laboratory that is offering such LDT for use by health care providers. We have begun the process of evaluating the final rule’s potential impact on our AVISE® tests, our operations, and our business more generally.

Litigation challenging the agency’s authority to take adopt this final rule is highly likely, although the outcome of such litigation is uncertain. Litigation challenging the final rule may also have an impact on the FDA’s plans to implement these new LDT requirements, making the potential implementation timeline somewhat uncertain. Affected stakeholders continue to press for a comprehensive legislative solution to create a harmonized paradigm for oversight of LDTs by both the FDA and CMS, instead of implementation of the FDA’s final rule, which may be disruptive to the industry and to patient access to certain diagnostic tests. However, this FDA rulemaking was initiated after years of failed congressional attempts to harmonize the regulatory paradigms applicable to LDTs and otherin vitro diagnostic tests, as discussed further below.

If the FDA implements the LDT final rule or Congress enacts comprehensive legislation to regulate in vitro diagnostics, such that the agency begins to exercise oversight over LDTs, or if the FDA disagrees that our marketed tests are within the scope of its criteria used for defining LDTs, we may become subject to extensive regulatory requirements and may be required to stop selling our existing tests or launching any other tests we may develop and to conduct additional clinical trials or take other actions prior to continuing to market our tests. If the FDA allows our tests to remain on the market but there is uncertainty about our tests, if they are labeled investigational by the FDA or if labeling claims the FDA allows us to make do not include the claims necessary or desirable for successful commercialization, orders from healthcare providers or reimbursement for our tests may decline.

In addition, as noted above, Congress had been working on legislation to create an LDT and IVD, regulatory framework that would be separate and distinct from the existing medical device regulatory framework. Reform legislation called the Verifying Accurate Learning-edge IVCT Development ACT of 2023 (the VALID Act) garnered bipartisan and bicameral support in recent years but failed to move out of committee during the last congressional session. As drafted and re-introduced for consideration by the current Congress, the VALID Act would codify the term IVCT to create a new medical product category separate from medical devices to include products currently regulated as IVDs as well as LDTs, among other provisions. The VALID Act would also create a new system for laboratories to use to submit their tests electronically to the FDA for approval, which is aimed at reducing the amount of time it would take for the agency to approve such tests and establish a new program to expedite the development of diagnostic tests that can be used to address a current unmet need for patients. Most recently, on March 21, 2024, the House Energy and Commerce held a subcommittee hearing titled “Evaluating Approaches to Diagnostic Test Regulation and the Impact of the FDA’s Proposed Rule.” The private witnesses testifying at the hearing expressed broad support for the bipartisan VALID Act instead of the FDA’s plan to use its medical device authorities to regulate LDTs.

If Congress were to pass the VALID Act or any other legislation applicable to the FDA’s regulation of LDTs, we will likely be subject to increased regulatory burdens such as registration and listing requirements, adverse event reporting requirements and quality control requirements. Any legislation affecting LDTs is also likely to have premarket application requirements prohibiting commercialization without FDA authorization and controls regarding modification to the tests that may require further FDA submissions. The premarket review process can be lengthy, expensive, time-consuming and unpredictable. Further, obtaining premarket clearance may involve, among other things, successfully completing clinical trials, which require significant time and cash resources and are subject to a high degree of risk, including risks of experiencing delays, failing to complete the trial or obtaining unexpected or negative results. If we are required to obtain premarket clearance or approval and/or conduct premarket clinical trials, our development costs could significantly increase, marketing of any new tests we may develop may be delayed, and sales of our existing tests could be interrupted or stopped. Any of these outcomes could reduce our revenue or increase our costs and materially adversely affect our business, prospects, results of operations or financial condition.

The outcome and ultimate impact on our business of the changes to the federal government’s regulation of LDTs is difficult to predict. It is unclear whether Congress will take action, through the VALID Act or otherwise, to supersede FDA’s recent final rule with comprehensive diagnostic reform legislation, or whether such legislation would be signed into law by President Biden. In addition, at this time it is unclear what testing and data may be required to support any required FDA clearance or approval of our tests, should the final rule be fully implemented as envisioned by FDA and HHS. Failure to comply with any applicable FDA requirements could trigger a range of enforcement actions, including warning letters, fines, penalties, suspension of operations, product recalls or seizures, denial of applications for clearance or approval, injunctions and other civil or criminal sanctions, which could have a material and adverse effect upon our business, operating results and financial condition.

Furthermore, should it be required in the future under either the final rule or legislative amendments, we cannot be sure that our AVISE® tests, or any new tests that we may develop, will be reviewed and authorized for marketing by the FDA in a timely or cost-effective manner, if authorized at all. Even if such tests are authorized for marketing by the FDA, the agency could limit the test’s indications for use, which may significantly limit the market for that product and may adversely affect our business and financial condition.