US-based Nanoscope Therapeutics presented key efficacy results from a Phase IIb trial investigating MCO-010 in patients with retinitis pigmentosa (RP).

MCO-010 is an ambient-light activable multi-characteristic opsin (MCO) optogenetic gene therapy for vision restoration in advanced RP. The FDA has granted MCO-010 both orphan drug and fast track designations.

The data analysis showed vision function improvements in patients who were treated with MCO-010. These results are consistent with previous studies as well as favourable safety profile.

The key efficacy endpoints were evaluated by using Multi-Luminance Y-Mobility Test (MLYMT), Multi-Luminance Shape Discrimination Test (MLSDT), and Best-Corrected Visual Acuity (BCVA) scores. Two or more luminance level changes in the MLYMT and MLSDT scoring system and a 0.3 LogMAR in the BCVA score were considered clinically meaningful.

One of the composite outcomes in key efficacy measures showed that 100% of the patients who were treated with MCO-010 showed vision improvement in the MLYMT, MLSDT or BCVA compared to 55.6% of the patients in the placebo arm.

Other composite measures looked at the combination of MLYMT or BCVA, MLYMT or MLSDT, and MLSDT or BCVA. In all scenarios, the treatment arms showed vision improvement compared to placebo cohorts.

Nanscope president Samarendra Mohanty said that single assessments cannot adequately capture clinically important changes in vision across a broad population. Therefore, the company used composite endpoints to evaluate overall vision function changes in a single measurement.

In addition, MCO-010 was well-tolerated with no serious or severe ocular or systemic adverse events reported. The most common ocular treatment emergent adverse events (TEAEs) across treatment arms were anterior chamber cells, ocular hypertension, and conjunctival haemorrhage.

The double-masked, sham-controlled trial (NCT04945772) enrolled 27 patients with severe vision impairment due to RP. 18 of the subjects were enrolled into two treatment arms, and nine patients received a sham intravitreal injection.

The trial evaluated a medium (0.9E11gc/eye) and a high (1.2E11gc/eye) single dose of MCO-010. The primary endpoint measured the efficacy of a single intravitreal dose. In March 2023, Nanoscope announced that the trial met the primary endpoint.

Co-founder and CEO Sulagna Bhattacharya said: “We look forward to our upcoming conversations with the FDA on the totality of this data regarding an expeditious path to market for this exciting therapy.”

RP is a group of rare genetic disorders in which the retina’s photoreceptor cells degrade over time. As a result, this leads to impaired vision and eventual blindness. These disorders are linked to over 100 different gene mutations. Approximately 100,000 people in the US and estimated 2 million people globally suffer from RP.