Electra Therapeutics Prices $350M IPO for sHLH Drug

Electra Therapeutics priced an upsized initial public offering at $350.0 million on 17 September 2026, one of the largest biotech IPOs of the year, to carry its lead antibody through a pivotal trial for a hyperinflammatory syndrome that kills a large share of the patients who develop it. Shares began trading on the Nasdaq Global Select Market the next day under the ticker ETRA.

What $350 million looks like, in four figures

$350.0Mgross IPO proceeds, upsized from the original marketed range

~$220Mof net proceeds earmarked for the Phase 2/3 SURPASS trial

$15.00price per share, the midpoint of a $14–$16 range

3expedited designations already held by ipsoprubart, across FDA and EMA

Figures from Electra's 17 September 2026 pricing announcement and SEC filings.

A $2.6 billion disease with one approved drug

Hemophagocytic lymphohistiocytosis is a hyperinflammatory syndrome in which an overactive immune system attacks its own organs; when it develops secondary to an infection, malignancy or autoimmune disease rather than an inherited gene defect, physicians call it secondary HLH, or sHLH. According to Research and Markets, the global HLH market was worth an estimated $2.59 billion in 2026, rising to roughly $3.24 billion by 2030. Only one drug, Sobi's emapalumab (Gamifant), carries an FDA approval for HLH at all — and its label covers primary, inherited HLH, not the secondary form Electra is chasing. Physicians treating sHLH still lean on a four-decade-old chemotherapy backbone, dexamethasone and etoposide, adapted from pediatric protocols never designed for the disease's adult, secondary form.

One report's $2.6 billion floor for HLH

$2.59B → $3.24B

Global hemophagocytic lymphohistiocytosis market, 2026 to 2030, as forecast by Research and Markets.

2026$2.59B

2028~$2.90B

2030$3.24B

Sources: Research and Markets, Hemophagocytic Lymphohistiocytosis Market Report 2026

Regulatory News outlook

We expect secondary HLH alone — the population ipsoprubart targets, distinct from the inherited disease Gamifant treats — to represent well over $1 billion of annual spend by the early 2030s if a targeted antibody reaches approval.

How we got here: Compounding the published $2.59 billion 2026 total at its own 5.8% CAGR out to 2032 (two years past the report's horizon, roughly when a pivotal readout could support a first approval) reaches about $3.6 billion; our estimate assumes secondary HLH, which most published case series put at a majority of diagnosed HLH in adults, accounts for at least a third of that spend once a therapy is approved specifically for it — an assumption, not a publisher's figure.

Blocking a whole receptor family, not one target

Electra Therapeutics built ipsoprubart around SIRP, a family of signal regulatory proteins that sits on the surface of myeloid cells and T cells and governs how aggressively the immune system attacks. Rather than blocking a single cytokine downstream of the damage — the approach behind Gamifant, which neutralizes interferon-gamma — ipsoprubart binds across the SIRPα, SIRPβ1 and SIRPγ receptors at once, aiming to deplete the pathological immune cells driving the hyperinflammatory cascade closer to its source. The company calls it a pan-SIRP approach; independent verification of that framing was not possible from the public record beyond Electra’s own pipeline materials.

Why two regulators moved early on one antibody

01

Two agencies, three designations

Ipsoprubart holds FDA Fast Track and FDA Breakthrough Therapy status plus the EMA’s PRIME designation — a rare combination for an asset still short of its first pivotal readout, and one that gets Electra rolling reviews and more frequent regulator contact on both sides of the Atlantic.

02

A pivotal trial already dosing

The Phase 2/3 SURPASS trial had already dosed its first patients before the IPO priced, according to the company — meaning a newly public company is executing, not merely planning, its registrational study.

03

A disease with one approved drug, and it isn’t for this population

Gamifant’s approval covers primary HLH; sHLH patients are treated off a decades-old chemotherapy backbone or off-label with agents built for other diseases. A first sHLH-specific approval would be a genuine category opening, not an incremental entrant.

“Receiving Fast Track designation for ELA026 reinforces the urgent need for effective treatment options for patients suffering from sHLH.” Kathy Dong, PharmD, President and CEO, Electra Therapeutics — from the company’s FDA Fast Track designation announcement

What sHLH doctors reach for today

Secondary HLH is typically triggered by an infection, a malignancy or an autoimmune flare, and it can kill within weeks without treatment. The default regimen, adapted from the pediatric HLH-94 and HLH-2004 protocols, pairs high-dose dexamethasone with etoposide, adding cyclosporine or intrathecal therapy for central-nervous-system involvement. When that backbone fails, physicians turn to agents approved for other diseases — emapalumab off-label, or immunomodulators such as anakinra and ruxolitinib — none of which carries an sHLH-specific approval or a trial built around this population’s biology.

Where ipsoprubart fits next to what exists

Product	Mechanism	Approval status in sHLH	Regulatory status	Administration
Ipsoprubart (Electra)	Pan-SIRP monoclonal antibody	Investigational; Phase 2/3 SURPASS dosing patients	FDA Fast Track, FDA Breakthrough Therapy, EMA PRIME	IV, dosing schedule not yet public
HLH-94 / HLH-2004 protocol	Chemotherapy (etoposide) plus corticosteroids	Standard of care, off-label in adults	No sHLH-specific designation	IV, multi-week protocol
Emapalumab (Gamifant, Sobi)	Anti-interferon-gamma monoclonal antibody	FDA-approved for primary HLH; used off-label in sHLH	FDA approved (primary HLH only)	IV infusion
Anakinra / ruxolitinib	IL-1 receptor antagonist / JAK1-2 inhibitor	Off-label, used in refractory cases	Approved for other indications, not HLH	Subcutaneous injection / oral

From published treatment guidelines and each product’s own labelling or announcements; not a clinical comparison.

Electra’s eight years, four financings

1. October 2018

   Incorporated

   Formed in Delaware as a subsidiary of Star Therapeutics LLC.

2. Series rounds

   Private financing, including a $183 million Series C

   Electra raised successive private rounds to advance ipsoprubart and its broader SIRP-targeted pipeline, culminating in a $183 million Series C.

3. 2026

   SURPASS Phase 2/3 dosing begins

   First patients dosed in the pivotal trial ahead of the company's public offering.

4. 17 September 2026

   IPO priced at $350.0 million

   Upsized from the original marketed range; 23,333,334 shares at $15.00.

5. 18 September 2026

   Nasdaq trading begins

   Shares began trading under the ticker ETRA on the Nasdaq Global Select Market.

6. Ahead

   SURPASS pivotal readout

   Timing not yet disclosed by the company.

What a newly public biotech still has to prove

Electra’s IPO landed inside a genuine rebound in biotech listings: BioPharma Dive counted eleven 2026 biotech IPOs that raised more than $300 million each, matching 2021’s pace and exceeding the prior four years combined. That appetite bought Electra the room to upsize rather than trim its offering — a signal investors are willing to fund a pivotal trial in a disease most people have never heard of, on the strength of three regulatory designations and patients already dosed.

• Trial completion: SURPASS is enrolling toward a pivotal readout; Electra has not disclosed a target completion date.
• Regulatory path: Three designations shorten review timelines but do not guarantee approval; ipsoprubart still needs positive Phase 2/3 data on an as-yet undisclosed primary endpoint.
• Cash runway: The company has not yet disclosed how far $350 million in gross proceeds, combined with existing cash, extends its runway.
• Competitive risk: Sobi and other sponsors could pursue an sHLH-specific label expansion or a competing mechanism before ipsoprubart reaches the market.

What is not yet public: an exact target date for SURPASS's primary readout, and the specific endpoint the trial is powered to hit. Electra's own disclosures, not analyst estimates, will settle both; this page will be updated when the company states them.

Frequently asked questions

How much did Electra Therapeutics raise in its IPO?

$350.0 million in gross proceeds, from 23,333,334 shares priced at $15.00 each — the midpoint of a $14–$16 marketed range. The offering priced 17 September 2026 and shares began trading on Nasdaq under ETRA on 18 September 2026.

What is ipsoprubart?

Ipsoprubart (development code ELA026) is Electra's pan-SIRP monoclonal antibody, designed to block the SIRPα/β1/γ receptor family and selectively deplete the pathological myeloid and T cells that drive secondary hemophagocytic lymphohistiocytosis (sHLH).

What designations does ipsoprubart hold?

FDA Fast Track and FDA Breakthrough Therapy designations, plus the EMA's PRIME (PRIority MEdicines) designation — three expedited-review statuses across two regulators for a single asset that has not yet reached approval.

What will the IPO proceeds fund?

Electra says roughly $220 million of the offering's net proceeds will fund its ongoing global Phase 2/3 SURPASS trial of ipsoprubart in sHLH, which had already dosed its first patients before the IPO priced.