Company: BLLN
Filing Date: 2025-06-20
Form Type: DRS
Source: 0000950123-25-006095
Chunk: 183

Company: BillionToOne, Inc.
Filing Date: 2025-06-20
Form: DRS
Chunk 183
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 Dramatic molecular response was observed, with the TMS dropping below 10,000. After the next cycle, TMS rebounded
to over 71,000, prompting the physician to switch therapy strategy and treat with encorafenib + cetuximab, the approved treatment for the BRAF V600E mutation that Northstar Select had detected.

The patient’s follow-up response demonstrated a significant decrease down to a TMS of 200, a decrease of more than 99.9% of
the tumor burden compared to the pre-treatment time point. While undergoing a perioperative treatment hold for a planned ileostomy reversal procedure, scans showed radiographic stable disease while TMS
demonstrated molecular progression and a rise in TMS to 2,800. Molecular progression detected by Northstar Response enabled better surgical treatment planning, and the patient resumed targeted therapy to control disease burden, indicated by a
falling TMS down to 670 at the latest collection date.

In this case, longitudinal sampling and observed changes in TMS via Northstar Response offered real-time
insights into the patient’s treatment response, while comprehensive profiling from the same blood draw by Northstar Select helped optimize the therapeutic strategy at several key time points. This case highlights how the synergistic use of
Northstar Select and Response can enable a physician to pivot to an alternative therapy expeditiously.

146

Commercialization

We
commercialize our UNITY and Northstar tests in the United States through our direct sales force targeting physicians in the prenatal and oncology markets, respectively. As of December 31, 2024, our clinician-focused sales organization included
137 sales representatives, with 120 in prenatal and 17 in oncology. In comparison, we had a total of 90 sales representatives at the end of 2023, 85 in prenatal and 5 in oncology. We plan to continue to expand our field sales force systematically,
as our prenatal sales force is less than one-third the size of our largest competitor and our oncology sales force is very small relative to many other liquid biopsy companies. Our sales representatives in
prenatal are engaged in educating OB-GYNs, MFMs, genetic counselors (GCs) and others about the existence, uniqueness and clinical utility of our offerings. Our sales representatives in oncology conduct similar
commercial and educational activities and primarily engage with oncologists. We have supplemented our direct sales team with medical science liaisons (MSLs) who are generally genetic counselors in