Adverum reports 5-year extension data on wet AMD gene therapy

Adverum Biotechnologies, Inc. released new 5-year data from a long-term extension clinical program evaluating ixoberogene soroparvovec (Ixo-vec), its gene therapy candidate under development for the treatment of wet age-related macular degeneration (AMD).

The late-breaking findings were reported during the American Society of Retina Specialists (ASRS) 2026 annual meeting in Montreal earlier this month.

Tell me about Adverum.

As a wholly-owned subsidiary of Eli Lilly, the clinical-stage gene therapy company is developing gene therapy candidates intended to target highly prevalent ocular diseases (including wet AMD).

This pipeline: Consists of durable, single-administration therapies designed for in-office use via a proprietary intravitreal (IVT) platform.

Key to these therapies: Adeno-associated virus (AAV) vector technology.

So where does Ixo-vec fit in?

This is the company’s lead asset—and the subject of three separate clinical programs for wet AMD.

Ixo-vec pairs the company's proprietary AAV capsid (AAV.7m8), with an aflibercept coding sequence to treat wet AMD.

Below, we’ll take a closer look at all the players involved in the entire process.

Starting with?

First, the AAV.7m8 platform.

Adverum describes its AAV.7m8 transgene delivery technology as engineering retinal cells that become "biofactories" and churn out sustained, robust levels of therapeutic protein across the retina.

For Ixo-vec, that "therapeutic protein" is aflibercept, an anti-vascular endothelial growth factor (anti-VEGF) protein.

Plus: The platform's peptide loop lets AAV.7m8:

Be delivered via intravitreal (IVT) injection
Cross the inner limiting membrane (ILM)
Transduce retinal cells

The result: Targeted delivery of the therapeutic payload at the site of the specific retinal disease—wet AMD, in Ixo-vec's case.

Take it back to the candidate.

Ixo-vec carries a vectorized aflibercept coding sequence under the control of a proprietary expression cassette optimized specifically for IVT injection.

The intended effect: Long-term VEGF inhibition.

And take note: The FDA previously granted Ixo-vec two FDA designations: Fast Track and Regenerative Medicine Advance Therapy (RMAT).

Next up: this clinical program evaluating Ixo-vec.

That would be the OPTIC clinical program, which investigated the gene therapy’s safety and efficacy via the:

Phase 1 OPTIC study (NCT03748784) during the first 2 years post-treatment
- Conducted among wet AMD patients who previously received anti-VEGF injections
OPTIC Extension trial (NCT04645212) as a 5-year extension for long-term patient outcomes
- The focus of the latest data set from ASRS 2026

As an aside: Ixo-vec has also undergone evaluation in the phase 2 LUNA trial (check out its 52-week topline data).

Both of these have already reported data, correct?

You bet. Adverum released 2-year findings from the OPTIC study in 2021, in which a single IVT injection of Ixo-vec demonstrated “sustained durability” and a “promising safety profile.”

Importantly: Investigators reported an over 80% reduction in annualized anti-VEGF injection frequency (for 2 x 10^11 vg/eye).
See here and here for the key efficacy and safety post-injection data, respectively.

And the OPTIC Extension trial?

We last reported 4-year data from this back in November 2024. A brief look at those follow-up results (which were similar to 3-year findings):

Patients continued to “experience long-term benefit from Ixo-vec” via vision maintenance, anatomical improvement durability, and sustained reduction in anti-VEGF treatment burden.
Patients had an 86% reduction in annualized anti-VEGF injections (see how that compared to the previous 3-year numbers).
Almost half of all patients were injection-free (prior year comparisons here).

Noted. So! How did the new 5-year data stack up to those prior numbers?

As presented by Szilárd Kiss, MD, FASRS, of Weill Cornell Medical College at Cornell University, this latest evaluation found that single Ixec-vec injection (2E11 vg/eye ) was well tolerated and resulted in:

Sustained ocular aflibercept concentrations
Visual acuity (VA) maintenance
Durable anatomic control
Marked reduction in anti-VEGF injections

As the paper abstract noted, this data represents “the longest reported follow-up to date in a trial evaluating IVT gene therapy among wet AMD patients.”

Let’s get some numbers.

Starting with baseline data from the 30 patients enrolled (and 15 receiving Ixo-vec):

Mean ± standard deviation (SD) BCVA: 65.4 ±7.4
Early Treatment Diabetic Retinopathy Scale (ETDRS) letters and mean central subfield thickness (CST): 407.1 ±172.5 m

Take note: Participants had received a mean of 9.9 ±1.3 annualized anti-VEGF injections in the prior 12 months, reflecting what investigators referred to as a “high-need population.”

And at 5 years?

A cumulative reduction of 87% in mean annualized anti-VEGF injections (compared to at 12 months prior to enrollment) was observed.

As for those other baseline numbers:

Mean (90% confidence interval [CI]) change in best corrected visual acuity (BCVA): –6.1 (–15.9, 3.7) ETDRS letters
Mean (90% CI) change in CST: –131.6 mm (–244.0, –19.2).

Next up: safety outcomes.

There were no observations of any new Ixo-vec-related ocular severe adverse events (SAEs)—including no hypotony, vasculitis, retinitis, choroiditis, or vascular occlusion.

Other notable findings:

Intraocular pressure (IOP) remained stable through 5 years.
All patients were inflammation-free at 1 year*.

*Take note: All but one patient remained inflammation-free through 5 years. That lone patient had inflammation first reported at 2.5 years after undergoing complex cataract surgery.

Definitely a positive report. So what’s next?

Ixo-vec is currently undergoing evaluation in the first of two planned phase 3 registrational trials—ARTEMIS (NCT06856577) and AQUARIUS (NCT07482176)—for its wet AMD indication.

Specifically: ARTEMIS is a U.S.-based study evaluating the safety and efficacy of Ixo-vec (6E10 vg/eye).

The participants: An estimated 284 wet AMD patients (treatment-naïve and previously treated)
- Clinical Trials lists an actual enrollment of 311
The setup: A single IVT injection of Ixo-vec (6E10 vg/eye) versus aflibercept (2 mg) will be administered every 8 weeks (Q8W)
The primary outcome: Mean change from baseline in BCVA at 1 year (average of weeks 52 and 56) with a non-inferiority (NI) margin of -4.5 letters

To note: The study will follow FDA guidance in administering three loading doses of aflibercept to patients prior to receiving Ixo-vec.

And the latest update from this trial?

As Adverum shared in September 2025: Full participant enrollment was anticipated by Q4 2025, with an accelerated topline data readout expected by Q1 2027.