Company: BLLN
Filing Date: 2025-10-17
Form Type: S-1/A
Source: 0001193125-25-242632
Chunk: 195

Company: BillionToOne, Inc.
Filing Date: 2025-10-17
Form: S-1/A
Chunk 195
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 of an ultra-sensitive response monitoring assay (Northstar Response v2), which can detect tumor DNA in blood down to a limit of detection (LOD) of 0.01%, can be technically equivalent to an early detection test for cancer. We expect that any products we launch for MRD will be laboratory developed tests (LDTs), and the products would not

| 39 |     | See our patent for “Quality Control Templates for Ensuring the Validity of Sequencing-Based Assays” U.S. Patent No. 11,629,381. See section entitled “Intellectual Property” for more information. |

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be subject to FDA approval requirements. 40Longer term, we believe that our smNGS-based technology could address the sensitivity challenges of early-stage cancer detection; however, we have not yet started development in this area. 41 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 UNITY 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. 42 Our UNITY Fetal Risk Screen directly addressed these challenges and is the first test that uses cfDNA to provide precise fetal risk assessments for recess