AptaTargets and the EIC Accelerator: A Stroke Drug Licensed to Merck

AptaTargets, founded in Madrid in 2014 by David Segarra and Maria Eugenia Zarabozo, developed ApTOLL, a first-in-class aptamer drug that blocks the Toll-like receptor 4 to damp the inflammation that damages the brain after an ischemic stroke. In its Phase 1b/2a APRIL trial, published in JAMA Neurology, mortality fell from 18% with placebo to 5% with ApTOLL, and the European Medicines Agency granted it PRIME priority status in 2023, according to AptaTargets. The EIC granted €2.5 million, which the company said came "at a key time to be able to initiate Phase 2b clinical trials" in 2024. The project received an EU contribution of €2,498,816 and ran from January 2024 to March 2026, according to CORDIS.

In October 2024 AptaTargets signed an agreement giving Merck global rights to develop and sell ApTOLL, for an upfront payment, development and sales milestones and royalties, according to AptaTargets. Merck's neurology development head said the company expected the programme "to enter Phase 2b in 2026". As of September 2026, no Phase 2b trial of ApTOLL appears on ClinicalTrials.gov or in the EU's CTIS register. The deal's financial terms have not been disclosed.

Where AptaTargets Stands Now

With ApTOLL in Merck's hands, AptaTargets provides transitional support. Its most recent news is from November 2025, when it and Merck were named finalists in the European Lifestars Awards for the transfer. Its latest filed accounts, for 2024, show annual turnover below €500,000 and share capital of €18,062, according to Empresia.

The Technology: A DNA Aptamer Against Inflammation

Aptamers are short strands of DNA or RNA that bind a target like an antibody. ApTOLL binds TLR4, a receptor that drives the immune response after brain tissue is starved of blood. It is given alongside thrombectomy, the mechanical removal of the clot. The CORDIS summary says only 20% of stroke patients are eligible for reperfusion treatment, and that earlier neuroprotective drugs have failed to show enough efficacy for approval.

What the EIC Award Promised, and What the Record Shows

The EIC money was meant to take ApTOLL into a Phase 2b trial. The project's report says AptaTargets designed and prepared late-stage trials, optimised manufacturing and ran non-clinical studies, and that it "achieved a major objective, signing a transaction with a big pharma", according to CORDIS. The Phase 2b trial itself had not started when the project ended.

1. Phase 2b preparationReportedProject report.
2. Phase 2b startNot startedNo registration.
3. Commercial partnerDeliveredMerck deal.
4. Related 2023 trialsRefused2023 applications not authorised.

The Money

AptaTargets has announced €14.4 million in public grants for ApTOLL since 2022, including €4 million through a Spanish science ministry consortium for the Phase 2b and €1.9 million from the Community of Madrid, some of it shared with hospital partners. Two consortium trials it applied for in 2023, one giving ApTOLL in ambulances and one in heart attack patients, are listed as "Not authorised" in the EU's CTIS register.

What Cannot Be Checked

Why Europe Should Care

Stroke strikes 15 million people a year, the CORDIS summary says, and earlier neuroprotective drugs have failed. A small European biotech getting a candidate this far and into a big pharma's pipeline is a real result. But the Phase 2b trial the EIC funded is now Merck's to run, and Merck says it expects Phase 2b to begin in 2026.

The Verdict

AptaTargets and the EIC have not been asked for comment for this article. It is based entirely on public records and published statements, linked throughout.