aibioCytomX files $250,000,000 stock offering, prices it at $5.300 a share
Tickers CTMX
CytomX priced 45,990,567 shares and pre-funded warrants for 1,179,245 more at $5.300 a share, below the $5.45 last reported sale price on March 17, 2026. Its lead clinical data are interim, and the prospectus gives no patient count or response rate.
Key facts
- Company
- CytomX Therapeutics, Inc. (NASDAQ: CTMX)
- News type
- Financings
- Primary source
- CytomX Therapeutics, Inc. 424B5 (2026-03-16)
CytomX Therapeutics, Inc. (Nasdaq: CTMX) priced an underwritten public offering in a final prospectus supplement dated March 17, 2026. The offering is for 45,990,567 shares of common stock and pre-funded warrants for 1,179,245 shares, at $5.300 per share. The price is below the $5.45 last reported sale price on March 17, 2026, which the prospectus cover gives. The company had filed a preliminary prospectus supplement the day before, on March 16, 2026, for $250,000,000 of common stock and pre-funded warrants, with the price and share counts left blank and a last reported sale price of $4.68 on March 13, 2026.
Who is selling the shares
Jefferies LLC, Piper Sandler & Co. and Cantor Fitzgerald & Co. are the representatives of the underwriters. Barclays Capital Inc. and Wedbush Securities Inc. are also named underwriters. The cover lists PacGrow as a co-manager, but the prospectus does not give that firm's full legal name. Jefferies LLC is allotted the largest block, 17,016,510 shares and 436,320 pre-funded warrants.
Jefferies LLC is also the sales agent under the company's at-the-market program. The prospectus says the underwriters have performed, and may perform, other banking and advisory services for CytomX, for which they received or will receive customary fees and expenses. Davis Polk & Wardwell LLP of Redwood City, California, represents the underwriters.
The money and the dilution
The underwriters have a 30-day option to purchase up to 7,075,471 more shares at the offering price. The underwriting discounts and commissions are $15,000,000 on the base offering, which leaves $234,999,992 in proceeds before expenses from a public offering price total of $249,999,992. The company estimates net proceeds of about $234.4 million, or about $269.6 million if the option is exercised in full.
The company says the money will go to continued development of Varseta-M and other pipeline programs, general corporate purposes and working capital. It may also use some of it to license intellectual property or purchase companies or assets, though it has no commitments to do so.
Before the offering, 170,186,365 common shares were outstanding as of December 31, 2025. The prospectus says 216,176,932 shares will be outstanding afterward, excluding pre-funded warrants, or 223,252,403 if the option is exercised in full. The prospectus warns that buyers face immediate and substantial dilution. The pre-funded warrants have an exercise price of $0.00001, and the company says it will not receive any meaningful additional funds when they are exercised. Holders may not exercise warrants that would take them above 9.99% beneficial ownership, a limit the holder can raise to 19.99% on 61 days' notice.
The prospectus also lists 5,769,231 shares issuable on Tranche Warrants at $3.77 per share, and 16,708,942 shares issuable on stock options outstanding at December 31, 2025.
The lead data and the cash position
On March 16, 2026, CytomX announced what the prospectus calls positive interim expansion data for Varseta-M, its antibody-drug conjugate aimed at EpCAM. The data come from an ongoing Phase 1 dose expansion study in advanced colorectal cancer, as of January 16, 2026. The prospectus gives no patient count and no response rate for those data.
The company's annual report, filed March 16, 2026, also says earlier high-affinity EpCAM antibodies were limited by pancreatitis and liver toxicities and discontinued. Varseta-M carries a topoisomerase-1 inhibitor payload licensed from AbbVie, formerly ImmunoGen. It puts existing later-line treatments for metastatic colorectal cancer at median progression-free survival of 2 to 5.6 months. The company plans to move Varseta-M into earlier lines of therapy with combination strategies starting in 2026. The report does not name a pivotal trial.
The annual report gives revenue of $76.2 million for 2025, down from $138.1 million in 2024. It reports a net loss of $17.4 million for 2025, after net income of $31.9 million in 2024. Cash used in operations was $75.6 million in 2025, against $86.2 million in 2024. Year-end 2024 cash and cash equivalents were $38.1 million, with short-term investments of $62.6 million. The prospectus does not state a year-end 2025 cash balance, so the new money cannot be set against the current cash position here.