Attovia Therapeutics Prices Upsized $289M IPO at Top of Range

Attovia Therapeutics priced its upsized initial public offering at $17.00 per share late Monday, raising $289 million after increasing the deal size by 45% from the original $200 million target. The San Carlos, California-based biotech offered 17 million shares, up from the 12.5 million originally filed, implying a fully diluted valuation of approximately $731.5 million. Shares are expected to begin trading on the Nasdaq Global Market under the ticker ATTO on Tuesday.

The upsizing signals strong institutional demand for immunology-focused biotech listings at a time when the IPO window has opened to earlier-stage companies. Pricing at the top of the $15 to $17 range with a 45% deal-size increase, Attovia is the first of three biotech IPOs expected this week; Braveheart Bio and Vogenx are scheduled to follow on August 6.

An IL-31 play in a Dupixent-dominated market

Attovia’s lead asset, ATTO-1310, is a half-life-extended fusion protein that inhibits interleukin-31, a cytokine central to itch signaling. The drug has completed dosing in a Phase 1 trial of 56 healthy volunteers, and preliminary Phase 1b data in patients with high-itch atopic dermatitis and chronic pruritus showed that 65% of patients met the company’s itch responder definition at Week 4 across two pooled dose cohorts. Phase 2 trials in chronic pruritus and high-itch atopic dermatitis are planned for the first half of 2027.

ATTO-1310 targets the IL-31 ligand directly, distinguishing it from Galderma’s Nemluvio (nemolizumab), which blocks the IL-31 receptor alpha subunit. Attovia argues the difference in target allows higher dosing and deeper itch relief through stronger pathway blockade. Nemluvio generated blockbuster revenue in 2025, and Galderma doubled its peak sales forecast to more than $4 billion this year, validating the commercial potential of IL-31 blockade.

The company’s ATTOBODY platform, in-licensed from Alamar Biosciences (which went public in April 2026), has produced two additional candidates still in preclinical development. ATTO-2306, a bispecific targeting IL-13 and IL-31, is in IND-enabling studies with a Phase 1 start planned for the first half of 2027. ATTO-1091, a trispecific targeting TL1A, IL-23, and integrin α4β7 for inflammatory bowel disease, is also in IND-enabling studies.

Financial position

Attovia had raised $255.8 million across Series A, B, and C rounds backed by Deep Track Capital, Frazier Life Sciences, Goldman Sachs Alternatives, and venBio. As of March 31, 2026, the company held $126.8 million in working capital. It posted a net loss of $64.1 million on $1.4 million in collaboration revenue for the 12 months ended March 31, 2026.

Morgan Stanley, Leerink Partners, Citigroup, RBC Capital Markets, and LifeSci Capital are the joint bookrunners. Goldman Sachs Alternatives, not acting as an underwriter, holds a 5.7% stake through an affiliated entity.

What to watch

The IPO proceeds, combined with existing cash, extend Attovia’s runway to fund Phase 2 trials for ATTO-1310 and IND-enabling work for the bispecific and trispecific programs. The key question for investors is whether direct IL-31 ligand targeting can produce clinically meaningful differentiation against entrenched competitors, particularly Nemluvio and the broader IL-4/IL-13 class led by Dupixent. Phase 2 data in 2027 will provide the first real test.

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Source: Reuters, Renaissance Capital, IPOScoop, FierceBiotech