Trans Sodium Crocetinate (TSC) to Improve Oxygenation in COVID-19

Background

Trans Sodium Crocetinate (TSC) is a bipolar synthetic carotenoid under development as a drug to enhance oxygenation to hypoxic tissue in addition to standard of care. TSC acts via a novel mechanism of action, improving the diffusivity of oxygen in blood plasma. Thus, it is based on physical-chemical principles, unlike most drugs which are based on biochemistry-based mechanisms. We explored the use of escalating doses and multiple daily dosing of TSC as a potential therapeutic for patients suffering from hypoxemia due to SARS-CoV-2 infection.

Methods

Individuals ≥18 years who were hospitalized with confirmed SARS-CoV-2 infection and hypoxemia, defined as SpO₂ < 94% on room air or requiring supplemental oxygen, WHO ordinal scale 3 through 7 (exclusive of Extra Corporeal Membrane Oxygenation [ECMO]) were enrolled in cohorts of six subjects, each of whom received the same dose (0.25, 0.5, 1.0, or 1.5 mg/kg) of TSC via intravenous bolus every 6 hours in addition to standard of care (SOC).

This report describes the safety and efficacy results from the lead-in phase of the study and the population pharmacokinetics (PK) analyses. Safety was assessed as the number of serious adverse events and dose-limiting toxicities (DLTs) observed with each dose. Several efficacy parameters were examined in the lead-in phase and descriptive statistics of efficacy parameters are provided. No formal statistical analyses were performed. The population PK analyses were based on previous analyses and examination of the concentration profiles, and two-compartment linear pharmacokinetic models were evaluated and validated. Covariates, including body size, age, sex, organ function, and dose level, were evaluated for inclusion into the model.

Results

TSC was well tolerated. There were no treatment emergent adverse events (TEAEs) reported. There were 2 serious adverse events (SAEs) reported during the study, neither were considered treatment-related. A total of 24 (96%) subjects survived. One subject (4.0%) died during the study as a result of an SAE (respiratory failure), and that event was determined to be due to COVID-19 complications and not related to study drug.

There was an observed reduction in the time to improvement in WHO Ordinal Scale with increasing dose. The median time to 1-point reduction in subjects receiving 0.25 mg/kg was 11.5 days versus 7.5 days in the 1.5 mg/kg treatment cohort. The overall range across all doses was 1 day to 28 days. A total of 36.0% of subjects had a 1-point improvement in WHO Ordinal Scale to Day 7. The 1.5 mg/kg dose resulted in observed superior outcomes for multiple secondary clinical outcomes: time to 1-point WHO Ordinal Score improvement through Day 29/discharge, 1-point improvement by Day 7, days to return to room air, and hospital length of stay.

The PK results showed that the two-compartment model fit the data well. Clearance decreased with increasing dose level and there was no evidence that clearance was affected by covariates other than dose level.

Conclusions

These findings suggest that TSC administration every 6 hours at doses up to 1.5 mg/kg for up to 15 days is safe and well tolerated with predictable pharmacokinetics and demonstrated an observed clinical benefit in the treatment of COVID-19-related hypoxemia.

(<ext-link xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="uri" xlink:href="http://ClinicalTrials.gov">ClinicalTrials.gov</ext-link> number, <ext-link xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="clintrialgov" xlink:href="NCT04573322">NCT04573322</ext-link>)