Company: RCUS
Filing Date: 2025-08-06
Form Type: 10-Q
Source: 0001724521-25-000101
Chunk: 285

Company: Arcus Biosciences, Inc.
Filing Date: 2025-08-06
Form: 10-Q
Item: Part I, Item 8
Chunk 285
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 could harm our product development strategy or prevent us from realizing the full commercial potential of our investigational products. 

Companion diagnostics are subject to regulation by the FDA and comparable foreign regulatory authorities as a medical device and may require separate regulatory authorization prior to commercialization of either the companion diagnostic or the relevant investigational product. According to FDA guidance, if the FDA determines that a companion diagnostic device is essential to the safe and effective use of a novel therapeutic product or indication, the FDA generally will not approve the therapeutic product or new therapeutic product indication if the companion diagnostic is not also approved or cleared for that indication. Depending on the data from our clinical trials, we may utilize diagnostic tests, during our clinical trial enrollment process to help identify patients with characteristics that we believe will be most likely to respond to our investigational products. For example, certain clinical trials that we are conducting, such as our STAR-221 trial, use a diagnostic test to measure PD-L1 levels in tumor samples provided by enrolled patients. Our future trials may also use a diagnostic test to help identify eligible patients. In addition, we have significant efforts directed to identifying changes in various cells and proteins to understand their relationship, if any, to the clinical activity observed in our clinical trials and to assess if such cells and/or proteins could be used as predictive biomarkers to select for patients more likely to respond to our investigational products. However, we cannot be certain that we will be able to identify any such biomarkers, that such biomarkers will result in us identifying the appropriate patients for our investigational products or that we or any third-party collaborators will be able to validate any diagnostic tests incorporating any predictive biomarkers we may identify. 

We currently do not have any plans to develop diagnostic tests internally. We are therefore dependent on the sustained cooperation and effort of third-party collaborators in developing and, if our investigational products are approved for use only with an approved companion diagnostic test, obtaining approval and commercializing these tests. If these parties are unable to successfully develop and obtain marketing authorization for companion diagnostics for use with any of our investigational products, or experience delays in doing so, the development of our investigational products may be adversely affected and we may not be able to obtain marketing authorization for these investigational products. Furthermore, our ability to market and sell, as well as the commercial success, of any of our investigational products that require a companion diagnostic will be tied to, and dependent upon, the receipt of required regulatory authorization and the continued ability of such third parties to make the companion diagnostic commercially available