Levocarnitine for Dry Eye in Sjogren's Syndrome

What Was Tested

In this phase 2 trial, researchers set out to test L-Carnitine.

This will be a crossover study design with all participants receiving both levocarnitine and placebo.

It had two arms (groups): Experimental: Levocarnitine, Placebo (experimental) and Experimental: Placebo, Levocarnitine (experimental).

The registry classes the interventions as drug.

More on the Plan

A phenome wide association study (PheWAS) was conducted for variants in the SLC22A5 gene encoding the OCTN2 protein.

OCTN2 is a cell membrane protein that transports carnitine into the cell.

The carnitine supplement levocarnitine, FDA approved for human use and with a favorable safety profile, was identified for repurposing.

SLC22A5/OCTN2 are a class of sodium ion dependent, high affinity transmembrane proteins expressed in the heart, liver, muscle, and kidney among other tissues.

Who Took Part

Enrollment: 15 actual participants took part.

It was open to people of any sex aged from 18 years up to 75 years.

Healthy volunteers were not accepted; participants needed the condition being studied.

Examples of who could join: Clinician diagnosis of primary or secondary SjS. Diagnosis of keratoconjunctivitis sicca defined by OSDI ≥ 25 and Schirmer's test ≤ 5mm/5min in at least 1 eye. Stable medications for past 4 weeks.

The full record lists 4 inclusion and 30 exclusion criteria; among the exclusions: age \<18 or \>75 at screening visit; unwilling or unable to stop the use of any artificial tear formulations containing l-carnitine; taking any form of levocarnitine supplementation or nutritional supplements containing l-carnitine within 2 months prior to enrollment.

How the Study Was Run

The set-up was randomized, crossover and single-blind.

Random assignment meant chance, not the researchers, decided who got L-Carnitine and who got the comparison, which limits bias.

In the crossover set-up each of the participants took both L-Carnitine and the comparison in turn, acting as their own control.

In this single-blind L-Carnitine study one party knew the assignments and the other did not.

Those kept unaware of assignments: outcomes assessor.

It started in 2021-11-17 with completion listed for 2025-09-19.

It ran at 1 site in United States.

Its stated primary purpose is treatment.

What Was Measured

Researchers chose this as the main measure: Mean change in tear inflammatory cytokine milieu (time frame: 14 weeks).

It also tracked 10 secondary outcomes, for example Ocular Surface Disease Index (OSDI), Mean change in tear carnitine levels, EULAR Sjogren's Disease Activity Index, EULAR Sjogren's Syndrome Patient Reported Index, EULAR Sicca Score and Patient Global Assessment.

What This Means in Plain Language

Put simply, this is a phase 2, randomized trial of L-Carnitine in 15 people.

Its size is small, so on its own it can only give an early look.

The trial is marked completed; no results are posted to the registry yet, so nothing here describes outcomes.

More context: the L-Carnitine compound page, all human trials.