ELX-02 has demonstrated clinically relevant improvement in the percent predicted forced expiratory volume (ppFEV1) of patients with class 1 cystic fibrosis (CF) with at least 1 nonsense mutation in the phase 2 combination trial sponsored by Eloxx Pharmaceuticals.

The results of the final data assessment, which included 13 patients versus 11 at time of initial assessment, showed that ELX-02 stabilized disease overall and resulted in a clinically relevant increase in ppFEV1 in 6 of 13 patients. These findings were based on change in ppFEV1 at the end of treatment at day 35 compared with the start of treatment at day 1.

“We believe that the clinical improvements with ELX-02 observed in a trial of CF patients with severe illness, coupled with remission observed in one patient in the ongoing phase 2 trial of ELX-02 in Alport syndrome patients with nonsense mutations, reinforces our belief in the disease-modifying potential of ELX-02 and warrants further development,” said Sumit Aggarwal, president and CEO of Eloxx.

The phase 2 combination trial was designed to assess safety and biological activity of ELX-02 monotherapy and in combination with ivacaftor after 5 weeks of treatment in patients with class 1 CF harboring the G542X nonsense mutation.

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Six of 13 patients entered the trial from the monotherapy arm (after average 463 days) and had a decrease in lung function (annualized reduction in ppFEV1, −4.26%) due to disease progression.

Initial topline results from this trial were reported in September 2022 and confirmed ELX-02 biological activity. Patients with higher baseline sweat chloride levels had increased responses to treatment.

Moreover, the results indicated that ELX-02 was generally well tolerated, with no treatment-related serious adverse events reported.

The final data assessment includes a reanalysis of the previously announced results, using change in ppFEV1 from day 1 instead of baseline. The reanalysis was conducted as multiple patients experienced disease progression between screening and treatment.

“Similar to the patients in this CF trial, participants in our phase 2 Alport syndrome trial also had highly progressive autosomally recessive disease, making a remission in even one patient highly clinically significant. The body of data strongly validate our decision to advance ELX-02 into a pivotal study in Alport syndrome,” said Sumit.

“The high concentrations of ELX-02 observed in the kidney in those with Alport Syndrome make the disease an ideal target for further study, as the ELX-02 exposure in the Alport study is at least 25-fold higher than in the CF trial.”


Eloxx Pharmaceuticals announces final data assessment from phase 2 combination clinical trial of ELX-02 in class 1 cystic fibrosis (CF) patients. News release. Eloxx Pharmaceuticals, Inc.; June 14, 2023.