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PP-007

PP-007, also known as SANGUINATE®, is PEGylated bovine carboxyhemoglobin, administered by IV infusion, in development for treating Acute Ischemic Stroke.

At a glance

What it is
High-affinity oxygen carrier that's designed to release oxygen at hypoxic tissues
Lead indication
Acute Ischemic Stroke due to anterior large vessel occlusion (A-LVO), alongside standard of care
Status
Phase 1/2 (HEMERA-1) complete · Pivotal Phase 3 (HEMERA-2) planned
FDA designations
Acute Ischemic StrokeBreakthrough Therapy (Apr 2026)Fast Track (Oct 2024)Sickle Cell DiseaseOrphan Drug (Apr 2015)
Human experience
Over 300 people dosed across 12+ clinical studies
Format
500 mL ready-to-use IV bag

Key issue: hypoxia

When oxygen can't reach tissue, damage follows

Every cell in the body depends on a steady supply of oxygen. When blood flow is blocked or oxygen-carrying capacity falls, tissue becomes hypoxic, and injury can begin within minutes. Hypoxia is a common thread across many serious diseases, and few therapies address it directly.

Acute Ischemic Stroke
Sickle Cell DiseaseSubarachnoid hemorrhage
Severe anemiaKidney transplant
Oncology

A proprietary PEGylation process

PEGfinity incorporates polyethylene glycol (PEG) to improve pharmacokinetics, modify oxygen affinity to selectively target hypoxic tissues, reduce immune reaction, and extend circulation time.

Prolong's founders come from the work behind the first FDA-approved PEGylated protein. Read the full story.

More than 700× smaller than a red blood cell

At nano-scale (<0.01 µm), PP-007 is designed to travel through narrowed and partially constricted vessels, including collateral routes.

How PP-007 is designed to work

  1. In the vessels

    CO comes off first

    The small amount of carbon monoxide it carries is released, and it aims to relax vessels and dampen inflammation.

  2. In oxygen-rich areas

    Oxygen binds

    Oxygen is expected to replace any remaining CO on the carrier.

  3. In starved tissue

    Oxygen comes off where it is low

    It binds oxygen tightly (P50 of ~12 mmHg vs. ~26 mmHg in red blood cells), which is expected to favor oxygen release where tissue levels are low.

FAQ

  1. Experience in people

    How many people have received it?

    300+ across 12 clinical studies in stroke, Sickle Cell Disease, severe anemia, kidney transplant and more.1

  2. FDA

    Has the FDA given it a faster path?

    2026 Breakthrough Therapy designation in April 2026, after Fast Track designation in 2024. Both bring closer FDA guidance and expedite review timelines.2,3

  3. Animal models

    Does it limit brain damage during a stroke?

    >62% less brain tissue lost than predicted, against ~13% with saline, in dogs with a permanently blocked artery. Blood flow to the blocked area recovered by about 24% of normal, against almost none with saline.4

  4. HEMERA-1

    Do more stroke patients recover when it is added to standard of care?

    67.5% of 40 A-LVO patients were living independently at 90 days or earlier when treated with PP-007, against 46.7% expected with standard of care alone.5

HEMERA-1 in detail, and HEMERA-2

1Prolong data on file2Prolong, Apr 2026 (opens in a new tab)3Prolong, Oct 2024 (opens in a new tab)4Christoforidis, J NeuroInterv Surg 2022 (opens in a new tab)5Prolong, World Stroke Congress 2025 (opens in a new tab)