Sodium Phenylbutyrate and Taurursodiol: A New Therapeutic Option for the Treatment of Amyotrophic Lateral Sclerosis

Abstract

Objective: To review the safety and efficacy of sodium phenylbutyrate and taurursodiol (SP + T) in slowing progression of amyotrophic lateral sclerosis (ALS) compared with pre-existing therapies.

Data sources: A PubMed (from January 1, 2009, to April 13, 2023) and ClinicalTrials.gov search conducted using sodium phenylbutyrate, taurursodiol, AMX0035, riluzole, and edaravone. Additional articles were identified by hand from references.

Data selection and data extraction: This included English-language articles evaluating SP + T efficacy or safety in humans for decreasing neuronal death and slowing the progression of ALS.

Data synthesis: In one phase II clinical trial that encompassed an open-label extension phase, disease severity, assessed by the rate of decline in overall score on the Amyotrophic Lateral Sclerosis Functional Rating Scale-Revised with higher scores indicating more functional ability, was -1.24 points per month with active drug and -1.66 points per month with placebo (difference, 0.42 points per month; 95% CI, 0.03-0.81; P = 0.03). Post hoc analysis found survival benefit of median 4.8 months with active medication compared with placebo.

Relevance to patient care and clinical practice in comparison with existing drugs: SP + T is a new US Food and Drug Administration-approved oral suspension for the treatment of ALS. Patients who received active medication through the phase II trial showed decreased rates of disease progression. Overall, SP + T could be considered a potential agent for the treatment of ALS which has a high unmet need.

Conclusion: SP + T is an option for the treatment of ALS; however, additional data regarding efficacy in phase III trials with long-term safety profile considerations, as well as trials to compare current therapy with SP + T, are needed.

Keywords: amyotrophic lateral sclerosis; new drug approvals; sodium phenylbutyrate; taurursodiol.