Eloxx Pauses Phase 2 Trials of ELX-02 in Cystic Fibrosis Due to COVID-19

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by Vanessa Pataia |

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ELX-02 trials pause

Eloxx Pharmaceuticals has temporarily paused enrollment in Phase 2 clinical trials of ELX-02 in cystic fibrosis (CF) patients in response to the COVID-19 pandemic.

According to Eloxx, the decision was made to avoid unnecessary exposure of CF patients, who are more at risk of COVID-19, and support global healthcare providers in their commitment to ensure patient safety.

“Enrollment in our Phase 2 clinical trials in cystic fibrosis has been temporarily paused as the health and safety of our employees, healthcare workers, and patients must be our highest priority during this crisis,” Gregory Williams, PhD, CEO of Eloxx, said in a press release. 

ELX-02 is an experimental treatment targeting nonsense mutations in the CFTR gene, which cause CF. These mutations create a premature stop signal in the gene, leading to the production of an incomplete CFTR protein that is quickly degraded by the cell.

ELX-02 works by instructing the ribosome — structures in the cell responsible for synthesizing proteins — to skip over the stop signal. Theoretically, this enables the production of sufficient amounts of full-length CFTR protein.

Results from Phase 1 trials of ELX-02 showed that the therapy was well-tolerated in single- and multiple-ascending doses in healthy volunteers. Preclinical data also demonstrated that ELX-02 was able to raise the levels of CFTR protein in patient-derived organoids — 3D models of “mini-organs” that mimic human tissue.

Before the temporary halt, Eloxx was enrolling patients with at least one copy of the G542X allele, the most common nonsense mutation in CF patients, in its two open-label, dose-ascending Phase 2 trials called EL-004 (NCT04126473) and EL-012 (NCT04135495). 

The goal of the trials is to evaluate the safety and tolerability of multiple-ascending doses of ELX-02 in CF patients with this nonsense mutation. ELX-02’s pharmacokinetics and pharmacodynamics — how the therapy moves through and is processed by the body — will also be assessed.

EL-004 was recruiting up to 16 participants in Germany and Israel, whereas EL-012 was recruiting up to eight participants in the U.S

Earlier this year, Eloxx announced that enrollment for the two Phase 2 trials was nearly complete. However, in light of the COVID-19 pandemic, public health authorities worldwide have recommended that people at high risk stay at home as much as possible, and avoid non-essential doctor visits and unnecessary exposure to people and public spaces. 

According to Eloxx, CF patients, particularly those with nonsense mutations, have compromised lung function and may be at higher risk of severe illness if they contract COVID-19.

“In accordance with the guidance provided by the U.S. Centers for Disease Control, World Health Organization and national, state and local governments in the United States and abroad, we are taking appropriate steps to help flatten the COVID-19 infection curve and reduce the risk in the most vulnerable patients,” Williams said.

Eloxx initially anticipated reporting top-line data from the trials during the first half of this year. This temporary pause in trial enrollment is intended to help maintain the integrity of the data from the trials.

“COVID-19 is rapidly evolving and we continue to work closely with our clinical sites and investigators. We remain committed to completing enrollment in this Phase 2 proof of concept clinical trial program, and reporting top line data as soon as feasible. We will provide further updates when appropriate,” Williams concluded.