Pixium Vision SA announced 48-month results from its first-in-human (FIH) trial evaluating the safety and efficacy of its PRIMA photovoltaic retinal stimulation microchip for improving visual acuity (VA) following implantation in patients with severe central vision impairment due to dry age-related macular degeneration (AMD).
Let’s start with this company.
Established in 2011 and based in Paris, France, Pixium Vision is a bioelectronics and brain machine interface technology company that develops bionic vision systems to enable partial visual perception for patients with vision loss.
Now talk about this Prima System.
The PRIMA Bionic Vision System is designed to partially replace the normal biological function of the eye’s photoreceptor cells through electrical stimulation of the nerve cells within the inner retina, which in turn transmits visual information to the brain via the optic nerve.
The minimally invasive, subretinal implant includes three main components: a wireless retinal implant, pair of glasses with a camera and digital projector, and a pocket processor.
Click here for a visual.
To note, the system was granted Breakthrough Device Designation by the FDA in March 2023.
Now this clinical trial.
Originally initiated in April 2018, the early, open-label feasibility trial (NCT03392324) enrolled and implanted five atrophic dry AMD patients (age 60+) with the PRIMA System.
To note, at baseline: all patients presented with no foveal light perception and VA of logMAR 1.3 to 1.7 (Snellen equivalent: approximately 20/400 to 20/1000, respectively) in their worst-seeing study eye, according to investigators.
See here for complete participant criteria.
What was measured?
The primary outcome is near visual acuity (VA) assessed in patients 12 months after implantation.
Secondary outcomes included:
- Near VA and VA
- Measured 3, 6, 9 18, 24, and 36 months post-implantation
- Reading acuity tests (via Radner Reading Chart)
- Measured 6, 12, 24, and 36 post-implantation
- Quality of life (via Impact of Vision Impairment [IVI] Questionnaire)
- Measured 12, 24, and 36 months post-implantation
Did all patients complete the study?
The investigators noted that an implant in one patient was incorrectly inserted into the choroid and one patient died 18 months post-implantation due to non-study-related causes.
Gotcha. And these findings.
While all five participants met the primary endpoint, only Early Treatment Diabetic Retinopathy STUDY (ETDRS) data for three participants were reported (see above).Per the data: Without zoom [magnification], VA closely matched the pixel size of the PRIMA implant:
- 1.17 ± 0.13 pixels, corresponding to mean logMAR 1.39, or Snellen equivalent 20/500, ranging from 20/438 to 20/565.
And with zoom?
At 48 months, participants’ VA improved by 32 ETDRS letters compared to baseline (standard error [SE] 5.1; 95% Confidence Interval [CI 13.4,49.9], p<0.0001).
Further, the natural peripheral visual function in the patients’ treated eye did not decline following surgery when compared to the fellow eye.
Any adverse effects?
Per the study, the “vast majority” of related non-serious adverse events (AEs) took place within the first 6 months following implantation—”confirming the absence of longer-term safety issues,” the investigators wrote.
These included:
- Macular microcysts; three patients (two at 9-months post-implantation)
- Asymptomatic choroidal neovascular membrane (CNVM); one patient (31 months post-implantation)
Author conclusions?
The authors concluded that, after 4 years, the PRIMA Bionic Vision System used in patients with atrophic dry AMD was feasible and well-tolerated, providing a clinically meaningful improvement in VA up to eight ETDRS lines.
Further, the use of PRIMA glasses enabled the simultaneous use of patients' prosthetic central and natural peripheral vision. “Reduced pixel size in… future implants may further improve the prosthetic VA to even higher levels,” they wrote.
Lastly… what’s next?
Per Clinical Trials, the FIH trial is slated to conclude in December 2025.
In the meantime, Pixium expects to report a full data readout from its European pivotal study: PRIMAvera, an open-label, baseline-controlled, non-randomized, multicenter, prospective single-arm trial examining the PRIMA Bionic Vision System in dry AMD patients (NCT04676854).