Stuart Therapeutics, Inc. released initial results from a phase 3 clinical trial investigating ST-100 (vezoclmitide) ophthalmic solution for the treatment of dry eye disease (DED).
This news follows just over 18 months after the company initiated the first patient visit to kick off the study.
To start, what should we know about Stuart?
The clinical-stage biopharmaceutical company is focused on addressing common chronic ocular diseases—DED, glaucoma, myopia, and dry age-related macular degeneration (AMD).
Key to these areas of focus: A patented and proprietary therapeutic platform.
The platform: PolyCol.
- What it is: A synthesized polypeptide therapeutic.
- What it does: Functions as a direct tissue reparative for extracellular matrix (ECM) helical collagen membranes and structures within the eye.
- In other words: This is essentially the first technology to target damaged collagen in chronic ocular diseases.
- How it does this: By tackling and binding to specific areas of collagen damage impacted in chronic ocular diseases, with the potential added benefit of restoring cell signaling and healing those ocular tissues.
For a more in-depth rundown of this, click here.
And how does ST-100 come into play?
In the context of DED: PolyCol is designed to rapidly repair damaged collagen while concurrently recovering the corneal epithelium, corneal nerves, and reducing inflammation
- As such: ST-100—part of a novel drug class of collagen mimetic peptides and the company’s first candidate based on its platform—is formulated as an eye drop that provides rapid improvement in DED signs and symptoms.
Talk more about its clinical performance thus far.
Per the company, ST-100 appears to relieve DED symptoms as soon as the second day of use, as well as restore nerve function—leading to improvements in the lacrimal function unit (tear process).
- Further: The drop also reportedly comes with a “vastly superior speed of action compared to competing therapeutics.”
Wasn’t it evaluated in a phase 2 trial?
Yup. Specifically, a first-in-human (FIH) study (NCT05241470) that analyzed ST-100 in two (low and high) doses versus a placebo.
As we previously reported, the formulation:
- Met its pre-approved primary endpoint by achieving a statistically significant difference between the percentage of patients achieving a +10 mm in Schirmer’s tear test (STT) score at 28 days (p = 0.0266)
- Demonstrated significant results in several symptom and ocular surface staining scores as early as Day 7 of treatment
Next up: this phase 3 trial.
First, we’ll get into its setup:
- Design: A multicenter, randomized, double-masked, placebo-controlled study (NCT06178679)
- Participants: 172 (aged 18+) patients diagnosed with DED
- Dosings: A single dose of ST-100 (60 μg/mL) versus a placebo, administered bilaterally twice daily
- Duration: 7 weeks (49 days)
- Outcomes:
- Primary: Efficacy of ST-100 versus vehicle via STT (measured by number of patients with ≥ 10mm improvement from baseline at Day 29)
- Secondary: Efficacy of ST-100 versus vehicle for DED signs and symptoms at Day 15, as determined by nine different measurements (see here, including for other outcomes)
Alrighty, now to the initial data.
The 29-day findings determined that ST-100’s performance (via STT) exceeded its phase 2 outcome—but did not reach statistical significance because the placebo performed better than it did in the phase 2 trial.
The company also reported ST-100 “demonstrated industry-leading results” by:
- Achieving statistically significant Week 1 fluorescein staining improvement in multiple regions of the eyes of patients (onset and a clinically meaningful [20%] improvement on Day 4)
Exactly how significant was this fluorescein stain improvement?
The magnitude of ST-100’s stain improvement at Week 1 (versus placebo) was “greater than any reported result for any approved DED therapeutic or product,” according to Stuart.
That’s pretty significant … anything to report on visual function?
Yes! Compared to placebo, ST-100 achieved a “statistically significant visual function improvement” on Day 2.
What this indicated: Stuart noted that this further reinforced the formulation’s potential to “provide fast-acting resolution for dry eye signs and symptoms.”
Got it. So what did the company have to say about these results?
Generally speaking, President and CEO Eric Schlumpf shared that they were “pleased with the outcome” of the trial—but noted that an additional study is still required.
- The results “strongly suggest that ST-100 … can address the critical unmet needs in (DED)” as a fast, effective, and comfortable topical drop that provides patients with rapid relief, according to Schlumpf.
Go on …
Chief Medical Officer Jodi Luchs, MD, also noted that ST-100’s speed of onset, providing rapid ocular surface healing and treatment effects, "[appears] to be considered greater than those seen with currently approved (DED) therapeutics.”
Even more promising: The eye drop may have the potential to treat other ocular diseases impacting the cornea.
How exciting! So what’s next?
The company is reportedly finalizing plans for a second phase 3 trial using data based on this most recent study as a template for the trial’s design.
- And on the regulatory front: Stuart shared that it also intends to meet with the FDA to confirm this new trial’s design—as well as a regulatory path to approval for ST-100.
As always, stay tuned for more details in the near future!