Company: BLLN
Filing Date: 2025-09-17
Form Type: DRS/A
Source: 0001193125-25-206347
Chunk: 189

Company: BillionToOne, Inc.
Filing Date: 2025-09-17
Form: DRS/A
Chunk 189
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2.5 billion in the United States. 40

| 38 |     | Each of our genetic tests is a LDT. The FDA has historically taken the position that it has the authority to regulate LDTs as medical devices under the Federal Food, Drug, and Cosmetic Act, but it has generally                                     
 exercised enforcement discretion with regard to such tests. More recently, in 2024, the FDA passed a final rule to regulate LDTs as medical devices, but in 2025, a federal district court found that this rule exceeded FDA’s regulatory              
 authority, vacating the final rule. The FDA has decided not to appeal the decision. As a result, our molecular diagnostic products are not currently subject to FDA approval requirements. While LDT tests do not require FDA approval currently, they 
 are subject to state regulatory requirements, such as under New York States CLEP, which reviewed LDTs for accuracy. See “Risk Factors—Risks related to legal and regulatory matters–Our tests are currently marketed as LDTs, and                      
 future changes in FDA enforcement of LDTs could subject our operations to much more significant regulatory requirements.” See also “Business—Government Regulations—New York Laboratory Testing”                                                       |

| 37 |     | While we have not yet started development in this area, the research work for MRD and our Select and Response tests is a necessary precursor to early detection development. We also believe that there is significant                          
 potential for our smNGS platform to accommodate products in this area. We believe the molecular information provided by our tests can assist in predicting the diagnostic pathway that can confirm the presence and tissue of origin of cancer. |

| 39 |     | Riku, S., Herman, M., et al. (2022). Reflex single-gene non-invasive prenatal testing is associated with markedly better detection of fetuses affected with single-gene recessive disorders at lower cost. Journal of 
 Medical Economics.                                                                                                                                                                                                    |

| 40 |     | See “Management’s discussion and analysis of financial condition and results of operations—Key factors affecting our results of operations and performance” for more information regarding how 
 these total addressable markets are calculated, including material assumptions.                                                                                                                |

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Oncology products ONCOLOGY Select: Cancer treatment selection NORTHSTAR Response: Cancer treatment response monitoring Minimum Residual Disease (MRD): Cancer detection & surveillance post-surgery In Development Non-invasiveliquid biopsy tests are a rapidly growing approach to detect and measure tumor DNA, driven by