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EyesonGlance Article

Recent interim findings evaluating the use of Brightstar Therapeutics’ proprietary anterior keratoplasty procedure support this solution-based approach for treating limbal stem cell deficiency (LSCD).

The data was presented by Joshua Hou, MD, Brightstar’s chief medical officer, during the Eye Bank Association of America and the Cornea Society’s Cornea and Eye Banking Forum last month.

Let’s start with Brightstar.

Based in Lexington, Kentucky, the biotechnology company has developed patented technology to advance a pipeline of regenerative cell therapies for corneal (specifically, corneal dystrophies) and ocular surface diseases (OSDs).

Its current focus:

  • Persistent epithelial defects (PEDs)

  • LSCD

Its pipeline: Includes that patented technology (see the next section) as well as two candidates:

  • STR 0O2 (BrightMEM plus LSC)

  • STR 003 (BrightMEM plus retinal pigment epithelium [RPE] cells)

As an aside: The company secured Series A financing last year to support the launch of its corneal treatment. Read our coverage.

Back to this patent technology …

BrightMEM is a corneal allograft made from Descemet’s membrane (DM).

What it does: It’s designed to promote durable regeneration of the corneal epithelium while providing protection to the underlying stromal treatment.

  • To note: BrightMEM is aseptically processed from donated human tissue (cornea) in accordance with the FDA’s current Good Tissue Practices (cGTP) regulations.

And the procedure?

BrightMEM anterior keratoplasty (BMAK) is a surgical procedure in which the BrightMEM corneal allograft is transplanted onto the ocular surface.

In other words: This is a corneal transplant that promotes regeneration of the corneal epithelium.

  • Click here to see how the procedure works.

Now to this research.

Titled Descemet’s Membrane Anterior Keratoplasty (DMAK) for Treat of (LSCD) in Congenital Aniridia, this interim data was based on a non-randomized, interventional, non-comparative pilot phase 1 clinical trial (NCT05909735) conducted at one clinical site location (University of Minnesota).

Its purpose: To investigate the clinical efficacy of using BMAK as a corneal on-lay to promote corneal epithelialization in partial LSCD.

And the participant criteria?

Target enrollment was 20 patients (aged 18+) with the following criteria:

  • Arm 1: Diagnosed with partial LSCD and best-corrected visual acuity (BCVA) of 20/100 or worse

    • Note: Partial LSCD was defined as having having ≥25% intact limbus (≥3 non-continuous clock-hours) or ≥25% of the total corneal surface covered with normal corneal epithelium

  • Arm 2: Total or near-total LSCD with recurrent erosion or PEDs; BCVA of 20/100 or worse

See here for complete inclusion and exclusion criteria.

How was the study set up?

Participants in both arm 1 and arm 2 groups underwent transplantation of a DM corneal only (partial LSCD), with the worst seeing eye (or randomized, if vision was bilaterally equal) of these patients treated with superficial keratectomy.

  • The purpose: To remove any pannus and debride the central corneal epithelium (followed by the DME corneal only transplantation)

Then: All patients were followed for 6 months following transplantation, evaluated for improvement in VA and LSCD, and monitored for adverse events (AEs).

  • In the case of the arm 2 group: Participants were also evaluated for improvement in PEDs / recurrent erosions.

And what was measured?

Measured at 180 days following intervention, a total of primary outcomes were evaluated. These included:

  • Visual improvement

    • As measured by the difference in postop VA at postoperative week 1, month 1, month 3, and month 6—then compared to preop VA (Snellen VA)

  • Graft retention on slit lamp examination

  • Graft retention on slit lamp photography

  • Postoperative AEs needing treatment

    • Epithelial defects

    • Elevated intraocular pressure (IOP)

    • Infectious keratitis

Secondary endpoints included LSCD severity on:

  • Corneal neovascularization

  • Whorl-like epitheliopathy

  • Impression cytology

  • Confocal microscopy

Now to the findings.

During his presentation of interim findings, Dr. Hou reported that 13 participant cases (ages 19-68; average age of 48.5) were successfully re-epithelialized within one month postop.

Further: A notable decrease was observed in LSCD severity—“particularly in the density of whorl-like keratopathy.”

Did VA demonstrate improvement?

Yes, improvements were noted in both VA and keratopathy over time, and investigators also noted a reduction in central superficial neovascularization.

Of interest: All patients included in the study were reported to express interest in having their second eye treated following the trial’s conclusion.

What kind of adverse events were noted?

Observed AEs included:

  • Graft retention

    • Total dislocation (7.7%)

    • Graft wrinkling (15.4%)

    • Epi-ingrowth / partial dislocation (7.7%)

  • Late epithelial erosion (15.4%)

This sounds promising! So outside of that study, where else has this procedure been utilized?

The company reported to Glance that it has reviewed clinical outcomes for 43 patient cases from which they’ve received outcome data. Of those, the following stats were provided:

  • 85% of cases achieved re-epithelization

  • 93% retention rate was noted, with three reported dislocations

  • 35 days was the average healing time

Lastly … when will the full data from the pilot study be released?

December 2024, according to Brightstar.