CNM-Au8 shows survival benefit after 3.5 years: Analysis

CNM-Au8 may help limit nerve cell damage to improve outcomes, data show

Marisa Wexler, MS avatar

by Marisa Wexler, MS |

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After up to 3.5 years on the experimental oral treatment CNM-Au8, the chances of survival for people with amyotrophic lateral sclerosis (ALS) in the open-label extension of the HEALEY ALS platform trial was nearly 60% higher than for a group of patients given a placebo in previous studies.

That’s according to new data presented at the European Network for the Cure of ALS (ENCALS) meeting in Stockholm, Sweden, in a poster, titled “Long-Term CNM-Au8 Treatment Reduces Neurofilament Light Levels and Improves Survival: Results from the HEALEY ALS Platform Trial.”

“The long-term improved survival results up to 3.5 years compared to an established multi-study ALS dataset of more than 12,000 patients across multiple clinical centers provides further evidence to strongly support CNM-Au8 as a potential treatment for ALS,” Benjamin Greenberg, MD, head of medical at Clene Nanomedicine, the company developing CNM-Au8, said in a press release.

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CNM-Au8 designed to boost energy production in nerve cells

CNM-Au8 is a suspension of gold nanoparticles that’s designed to boost energy production in nerve cells. Nerves require a lot of energy for sending electrical signals, and defects in energy production have been linked to the development and progression of ALS and many other neurological disorders.

The HEALEY ALS Platform Trial (NCT04297683), launched in 2020, is a large study to test different potential ALS treatments simultaneously, using one overarching protocol to streamline logistics. One of the first arms of HEALEY tested CNM-Au8; 161 ALS patients were randomly assigned to take the therapy at one of two doses, or a placebo, for six months.

The study didn’t meet its main goal of showing that CNM-Au8 significantly slowed functional declines, but analyses indicated patients on the 30 mg dose were less likely to die or experience overall clinical worsening than those on a placebo.

After the placebo-controlled part of the study, most participants continued into an open-label extension in which all are receiving long-term treatment with 30 mg of CNM-Au8. Researchers now presented updated survival analyses from 70 evaluable patients who were followed for up to 3.5 years on CNM-Au8.

The researchers compared results from those patients against findings from patients given a placebo in previous ALS trials who were included in a large database called PRO-ACT. A previous comparison covering up to 2.5 years on CNM-Au8 indicated the therapy improved survival rates by 49%.

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Clene expanding CNM-Au8 expanded access program in US

Risk of death significantly lower in patients given CNM-Au8

Results now show the risk of death was 56.9% lower in patients given CNM-Au8 compared with placebo-treated patients in PRO-ACT. In fact, among patients on a placebo in PRO-ACT, slightly more than half had died after two years of follow-up. By contrast, for patients on CNM-Au8 in the HEALEY extension study, slightly more than half of the patients were still alive after 30 months (2.5 years) of follow-up.

The poster at ENCALS also included new data on CNM-Au8’s effect on neurofilament light chain (NfL), which is a well-established marker of nerve damage.

Data showed, for patients who were on CNM-Au8 throughout the entire study, average blood NfL levels were stable in the first six months, then gradually decreased, by 7.2%, after about 1.5 years of total follow-up.

In contrast, NfL levels rose notably in the first six months in the placebo group, then stabilized after these patients started on active treatment in the open-label extension. Still, by the end of 1.5 years total follow-up, NfL levels were on average 10.3% higher than at the start of the study.

A sub-analyses of 55 NfL “responders” — that is, patients who experienced a consistent decline in NfL levels with CNM-Au8 — showed average blood levels of NfL were decreased by approximately 28% after about 1.5 years of follow-up, and the decrease in NfL was more pronounced among patients who started with higher levels of this marker.

Collectively, these data support the idea that CNM-Au8 may help limit nerve cell damage to improve outcomes for ALS patients, according to researchers.

Clene is now investigating CNM-Au8 in ALS patients outside of clinical trials, as part of its expanded access program initiatives. Data from these programs and from the company’s RESCUE-ALS Phase  2 trial (NCT04098406), have also demonstrated the therapy’s ability to extend survival in people with ALS.