Every 424B that Zenas BioPharma, Inc. (ZBIO) has filed with the SEC in the last 12 months is listed below, newest first, and each one links through to the document itself with the summary and the scores our analysis gives it.
A 424B covers the supplement that carries the terms of a priced offering, so if you follow ZBIO and want that one kind of document rather than the whole filing history, this is the page to keep. The company's other filings, of every form, are on the full ZBIO filings page.
Zenas BioPharma is offering $200,000,000 aggregate principal amount of 2.50% convertible senior notes due 2032, with an underwriter option for up to $30,000,000 of additional notes. Interest accrues at 2.50% paid semi‑annually; maturity is April 1, 2032. The initial conversion rate is 37.7358 shares per $1,000 principal (approximately $26.50 per share). Conversions may be settled in cash, shares or a combination, and are permitted only upon specified triggers prior to January 1, 2032 and freely thereafter until maturity. The notes are unsecured senior obligations, effectively subordinated to secured debt and structurally subordinated to subsidiary liabilities. Expected net proceeds are approximately $193.7 million; intended uses include funding a potential U.S. commercial launch for obexelimab and advancing clinical programs.
Zenas BioPharma is registering a primary offering of 5,000,000 shares of common stock. The prospectus supplement states a public offering price of $20.00 per share for gross proceeds of $100,000,000 and estimated net proceeds to the company of approximately $94.0 million before expenses; the underwriters have a 30-day option to purchase an additional 750,000 shares.
The filing describes a concurrent public offering of 2.50% Convertible Senior Notes due 2032 in an aggregate principal amount of $200.0 million (or $230.0 million if the over-allotment is exercised). The supplement discloses recent positive Phase 3 topline results for obexelimab in IgG4-RD and a planned BLA submission in Q2 2026, and states the company expects the combined proceeds, existing cash, ATM sales and first tranche loan to fund operations into Q3 2028.
Zenas BioPharma is pursuing a securitized capital raise via an offering of convertible senior notes due 2032 and a concurrent equity offering. The company reported positive Phase 3 obexelimab results in IgG4-RD (56% reduction in risk of flare; Hazard Ratio 0.44, p=0.0005) and plans to submit a BLA in Q2 2026.
Earlier Phase 2 MoonStone RMS data showed a sustained reduction in new GdE T1 lesions through week 24. The company is advancing orelabrutinib into global Phase 3 programs (PriMroSe and Monarch) and expects to initiate additional IND-directed Phase 1 studies for ZB021 and ZB022 in 2026. Separately, Zenas entered a Loan Agreement providing for up to $250.0 million in term loans with an initial Tranche A of $75.0 million. The prospectus supplement describes conversion, redemption and repurchase features, ranking and material risks; offering size and many pricing fields are left blank in the provided excerpt.
Zenas BioPharma is offering shares of its common stock and is conducting a concurrent convertible notes offering. The prospectus supplement describes the proposed equity offering on an automatic shelf registration and a separate, concurrent public offering of convertible senior notes due 2032.
The company reported positive Phase 3 obexelimab results in January 2026 (Hazard Ratio 0.44, p=0.0005) and plans to submit a BLA for IgG4-RD in Q2 2026. It also reported confirmatory RMS Phase 2 data and expects topline SLE Phase 2 results in Q4 2026. On March 14, 2026, the company entered a loan agreement providing up to $250.0 million in term loans. The prospectus states intended uses of proceeds: support a potential U.S. commercial launch for obexelimab, advance orelabrutinib Phase 3 trials, fund ZB021 development, and for general corporate purposes.
The company is permitting resale of up to 8,533 shares of its Common Stock held by Crown Helix Strategies Ltd. under this prospectus supplement. These shares were transferred to Crown Helix Strategies Ltd. in December 2025 as part of an internal reorganization involving Crown/Long Short 41 Segregated Portfolio.
The supplement removes Crown/Long Short 41 Segregated Portfolio as a selling stockholder and adds Crown Helix Strategies Ltd. instead, without changing any other selling stockholders. Shares of Common Stock outstanding were 53,679,166 as of October 31, 2025; this is a baseline figure, not the amount being offered.