The FDA has accepted Genentech’s biologics license application for vamikibart, an investigational nonsteroid treatment for uveitic macular edema (UME), as new phase 3 findings showed that improvements in visual acuity and retinal thickness were generally maintained through 1 year. The company announced the regulatory development following a presentation of the MEERKAT and SANDCAT trial results at the American Academy of Ophthalmology (AAO) 2026 meeting in New Orleans.

Nisha Acharya, MD, MS, distinguished professor of ophthalmology at the University of California, San Francisco, presented the 52-week efficacy and safety findings from the trials during Retina Subspecialty Day on October 10. Vamikibart is a monoclonal antibody designed to inhibit interleukin-6 (IL-6), a proinflammatory cytokine implicated in UME. Dr. Acharya noted that macular edema frequently persists despite treatment of underlying uveitis and that corticosteroids, the mainstay of treatment, carry risks including elevated intraocular pressure and cataract formation.

The identically designed phase 3 MEERKAT and SANDCAT trials enrolled 245 and 256 adults, respectively, with UME associated with noninfectious uveitis. Patients were randomized equally to receive intravitreal vamikibart 0.25 mg, vamikibart 1 mg, or sham treatment at 4 monthly visits. The primary endpoint was the proportion of patients gaining at least 15 Early Treatment Diabetic Retinopathy Study (ETDRS) letters at week 16.

The trials produced differing primary endpoint results. In MEERKAT, 26.1% of patients receiving vamikibart 0.25 mg and 43.2% receiving 1 mg achieved gains of at least 15 letters, compared with 6.3% in the sham group. Both comparisons were statistically significant (P=.0008 and P<.0001, respectively).

In SANDCAT, the corresponding responder rates were 34.0%, 21.8%, and 13.3%. The 1-mg dose did not demonstrate statistical significance compared with sham (P=.1487), and the result for the 0.25-mg dose was considered nominally significant (P=.0019) under the trial's statistical testing hierarchy.

At week 52, the proportion of patients achieving at least a 15-letter gain remained numerically higher in both vamikibart groups than in the sham groups. In MEERKAT, responder rates were 28.3% with the 0.25-mg dose and 21.7% with the 1-mg dose, compared with 6.3% with sham. Both comparisons were nominally significant. In SANDCAT, responder rates were 23.4%, 17.3%, and 12.0%, respectively, without nominal statistical significance.

Dr. Acharya reported that improvements in best-corrected visual acuity and central subfield thickness (CST) appeared as early as day 8 and were generally maintained through week 52. The treatment difference in visual acuity narrowed in the SANDCAT 1-mg group by the end of the study.

Anatomic improvements persisted in both trials. At week 52, mean CST reductions in MEERKAT were 167.1 µm and 174.1 µm with the 0.25-mg and 1-mg doses, respectively, compared with 89.3 µm with sham. In SANDCAT, reductions were 188.1 µm and 192.8 µm with vamikibart, compared with 99.1 µm with sham.

The studies also assessed the need for additional treatment after the initial dosing period. Patients could receive rescue treatment beginning at week 4 for worsening vision, macular edema, or uveitis. Those who had not required rescue could receive masked, as-needed treatment beginning at week 20.

Dr. Acharya reported that more than half of sham-treated patients required rescue treatment, compared with approximately 20% of vamikibart-treated patients. Among patients eligible for as-needed dosing, approximately 30% required additional injections, and about 85% of those received only 1 additional injection.

Safety findings through 52 weeks showed relatively low rates of serious ocular adverse events and intraocular inflammation, Dr. Acharya reported. No cases of ocular occlusive retinal vasculitis were observed, and no new safety signals were identified during the as-needed treatment phase.

Dr. Acharya characterized the findings as evidence of sustained efficacy with a relatively low additional treatment burden. The week 52 data provide longer-term follow-up for a potential nonsteroid treatment option, although the differing primary endpoint results in MEERKAT and SANDCAT remain an important consideration in evaluating the overall evidence.

In a press release following Dr. Acharya’s presentation, Genentech said the FDA is expected to make a decision on the application by July 2027. If approved, vamikibart would become the first targeted nonsteroid intravitreal therapy for UME, the company said. Regulatory applications for vamikibart have also been accepted in the European Union, China, and Japan. RP