Q32 Bio (QTTB) investor relations material

Program updates and clinical progress

• Lead asset bempikibart is advancing in alopecia areata, with proof of concept established and focus on expanding clinical data in Part B of the SIGNAL-AA phase IIa study.

• Part B includes 33 patients, with top-line 36-week data expected midyear and 52-week durability data later this year; design changes include longer dosing, central review, and refined patient eligibility.

• Part A showed statistically significant hair growth and durable responses, especially in hard-to-treat and severe populations, with a favorable safety profile.

• Adjustments in Part B align patient duration with JAK studies, and preliminary PK data indicate faster achievement of steady state and extended exposure.

• Open-label extension initiated due to patient demand, focusing on safety, repeat dosing, and cycling efficacy.

Market opportunity and competitive landscape

• Alopecia areata market projected to reach $2.6 billion by 2030, with current treatments dominated by JAK inhibitors, which have limited penetration and safety concerns.

• Bempikibart aims to address unmet needs with a safer, durable, and potentially front-line biologic option, expected to expand and penetrate the market similar to biologics in other indications.

• Commercial strategy includes at-home, self-injectable dosing, aligning with established biologic paradigms and addressing patient and physician preferences.

• Biologics are anticipated to move ahead of JAKs in treatment sequencing, especially for moderate and chronic cases.

• Key product profile drivers are safety, efficacy, durability, and low injection site reaction rates.

Study design, endpoints, and risk mitigation

• Part B incorporates central review for eligibility, reduced episode duration, and direct site engagement to improve data quality and retention.

• Enrollment exceeded expectations, with strong interest from both physicians and patients across severity levels.

• Key efficacy endpoints are mean percent change in SALT and SALT 20, with SALT 20 being pivotal for phase III progression.

• Risk mitigation includes hands-on trial oversight and functional service model to minimize eligibility violations and ensure data integrity.

• Open-label extension data will inform on cycling, safety, and long-term efficacy.