Genentech’s Phase III MEERKAT and SANDCAT Trials Show Vision and Anatomical Gains With Vamikibart in Uveitic Macular Edema

Genentech has shared new data from the pivotal MEERKAT (NCT05642312) and SANDCAT (NCT05642325) clinical trials evaluating its investigational vamikibart for the treatment of uveitic macular edema (UME).¹

Vamikibart demonstrates vision and anatomical improvements in UME

Primary and secondary endpoint data from both studies show that treatment with vamikibart supports the potential for rapid improvements in vision and reductions in macular thickness (swelling in the back of the eye due to retinal fluid). This new data was presented at the American Academy of Ophthalmology annual meeting (AAO 2025) in Orlando, FL.

Vamikibart is a monoclonal antibody specifically engineered for intravitreal (IVT) administration that acts by targeting interleukin-6 (IL-6), a key cytokine in the inflammatory pathway in UME. According to Genentech, it is the first non-steroid targeted therapy designed to address inflammation driving UME.

In a press release, Levi Garraway, MD, PhD, Genentech’s chief medical officer and head of global product development, said: “The totality of data from these pivotal vamikibart studies represent an important step towards addressing a clear unmet need for people with uveitic macular edema. UME is a major cause of vision loss and blindness in people of working age. We look forward to discussing the data for this potential first-in-class treatment with regulatory authorities.”

Phase III MEERKAT and SANDCAT trial results

Detailed results from MEERKAT and SANDCAT show:

• In both trials, more patients treated with vamikibart experienced vision gains, with statistically significant superiority over sham in MEERKAT but not in SANDCAT.

• Key secondary endpoints showed rapid, clinically meaningful improvements in best corrected visual acuity (BCVA) and central subfield thickness (CST), supporting vamikibart’s efficacy.
• Variability in BCVA measurements and differences in baseline characteristics or concomitant medications may have contributed to outcome differences between trials.
• Vamikibart was generally well tolerated, with low rates of ocular adverse events and intraocular inflammation and no retinal occlusive vasculitis observed.
• The most common adverse events (≥5%) were conjunctival hemorrhage and increased intraocular pressure.

In the press release, Eric Suhler, MD, MPH, professor of ophthalmology at the Casey Eye Institute, Oregon Health & Science University, Portland, OR, and study investigator, added: “UME is most commonly treated with steroids that, when injected in the eye, are associated with significant side effects such as increased pressure in the eye, which can lead to glaucoma and cataract formation. These data seen across multiple endpoints in both Phase III studies, along with the overall low rate of treatment-related ocular adverse events, suggest that vamikibart could provide a clinically relevant, locally injectable non-steroid treatment option for people with UME.”

Trial design and endpoints

MEERKAT and SANDCAT are identical global, randomized, double-masked, sham-controlled trials evaluating IVT vamikibart in UME.

• Participants received 0.25 mg vamikibart, 1 mg vamikibart, or sham injections every four weeks for up to 16 weeks.
• The primary endpoint measured the proportion of patients achieving a ≥15-letter improvement in best corrected visual acuity at week 16.
• Key secondary endpoints included mean change from baseline in best corrected visual acuity and central subfield thickness at week 16.

Early evidence from the DOVETAIL study

In 2023, data from the Phase I DOVETAIL study (NCT06771271) evaluating vamikibart were presented at the Association for Research in Vision and Ophthalmology (ARVO) Annual Meeting.²

Early-phase findings from DOVETAIL showed:

• At 12 weeks, mean BCVA improved by +10.3, +9.5, and +8.4 letters for the 0.25, 1, and 2.5 mg doses, respectively, with a combined mean gain of +9.3 letters.
• Mean CST decreased by 124 μm, 177 μm, and 184 μm, respectively, with a combined mean reduction of 161 μm at 12 weeks.
• Improvements in both BCVA and CST were maintained during the observation period after treatment.
• All vamikibart doses were well tolerated, with no new safety concerns among the 33 treated patients.

References

1. Genentech Presents New Phase III Pivotal Data for Vamikibart in Uveitic Macular Edema (UME), a Serious Cause of Vision Loss. News release. Genentech. October 17, 2025. Accessed October 22, 2025. https://www.gene.com/media/press-releases/15082/2025-10-17/genentech-presents-new-phase-iii-pivotal

2. Sumit Sharma, Eric Suhler, Phoebe Lin, Meike Pauly-Evers, Daniela Willen, Robbie Peck, Federica Storti, Simone Rauhut, Tatiana Gott, Benedicte Passemard, Lachlan Macgregor, Zdenka Haskova, David Silverman, Sascha Fauser, Marina Mesquida; A novel intravitreal anti-IL-6 monoclonal antibody for uveitic macular edema (UME): preliminary results from the phase 1 DOVETAIL study. Invest. Ophthalmol. Vis. Sci. 2023;64(8):5100. https://iovs.arvojournals.org/article.aspx?articleid=2789443