Company: BLLN
Filing Date: 2025-10-07
Form Type: S-1
Source: 0001193125-25-233697
Chunk: 23

Company: BillionToOne, Inc.
Filing Date: 2025-10-07
Form: S-1
Chunk 23
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 yet started development in this area. 15 To date, we have launched multiple products across these large addressable markets. We performed approximately 508,000 smNGS-based tests in the last 12 months ended June 30, 2025, with significant room to further grow test volume in both markets. Prenatal products PRENATAL Fetal Risk Screen: Inherited conditions Aneuploidy Screen: Chromosomal + microdeletion conditions Fetal RhD + Fetal Antigen NIPT: Non-alloimmunized and alloimmunized pregnancies Traditional prenatal screening focuses on assessing a fetus’ risk for larger chromosomal changes. However, many common and severe conditions are the result of much smaller genetic changes, in single base pairs. These recessively inherited conditions, including SCD, alpha thalassemia, beta-thalassemia, CF, and SMA, are collectively more common than aneuploidy conditions like Down syndrome. Yet these conditions cannot be directly tested with traditional NIPT since each condition requires the precise quantification of fetal cfDNA. Given the technical challenges of directly assessing the fetal risk for these conditions, current medical guidelines recommend that every pregnant patient is offered carrier screening, with father screening then required if the mother is found to be a carrier. However, studies estimate that fewer than half of fathers complete the recommended screening due to barriers related to cost, availability, and willingness. As a result, approximately 58% of pregnancies affected by these recessive conditions are undetected by traditional screening workflows. 16 Our UNITY Complete Fetal Risk Screen directly addressed these challenges and is the first test that uses cfDNA to provide precise fetal risk assessments for recessive conditions without requiring a paternal sample. In

| 14 |     | Each of our genetic tests is an LDT. The FDA had historically taken the position that it had the authority to regulate LDTs as medical devices under the Federal Food, Drug, and Cosmetic Act but exercised enforcement                                 
 discretion until it recently rescinded LDT regulations indicating that it does not have the authority to require clearance, de novo classification, or approval of LDTs prior to market release. As a result, our molecular diagnostic products are not 
 currently subject to FDA approval requirements. While LDTs do not require FDA approval currently, they may be subject to state regulatory requirements. For example, many of our LDTs are approved by the New York’s Clinical Laboratory Evaluation     
 Program (CLEP), which reviews LDTs for accuracy.