for people ages 18-80 (full criteria)
at Orange, California and other locations
study started
estimated completion



This study will assess the effects and safety of PTC857 treatment in participants diagnosed with ALS.

Official Title

A Phase 2, Randomized, Double-Blind, Placebo-Controlled, Parallel Study to Assess the Efficacy, Safety, Tolerability, PK, and Biomarker Effects of PTC857 in Adult Subjects With Amyotrophic Lateral Sclerosis (CARDINALS)


Participants will be randomized to 1 of 2 treatment groups: PTC857 or matching placebo. Following successful completion of the 24-week Treatment Period, participants have the option to receive open-label PTC857 in the Long-term Extension Period for 28 weeks.


Amyotrophic Lateral Sclerosis, Motor Neuron Disease, Sclerosis, PTC857


You can join if…

Open to people ages 18-80

  • Males or females aged between 18 and 80 years with a body mass index between 18 and 35 kilograms/meters squared
  • ALS with preserved function, defined as:
    1. Onset of the first symptom leading to the diagnosis of ALS ≤24 months at the time of the initial Screening Visit
    2. Revised EL Escorial criteria of either:

    (i) Clinically definite ALS (ii) Clinically probable ALS

  • A total ALSFRS-R score of at least 34 at the start of the Screening Period
  • No significant respiratory compromise as evidenced by slow vital capacity ≥60% at the start of the Screening Period
  • All concomitant medications (both prescription and over the counter), including standard-of-care therapy riluzole, edaravone, or sodium phenylbutyrate/taurursodiol, and non-pharmacologic therapy regimens should be stable and unchanged from 30 days prior to the start of the Screening Period and intend to remain stable and unchanged throughout the course of the study
  • Female participants must have a negative breast cancer imaging screening status (not considered clinically abnormal and/or requiring further evaluation/treatment) within 6 months prior to the Screening Visit, or during the Screening Period.

You CAN'T join if...

  • Females who are pregnant or nursing or plan to become pregnant during the study
  • Participants with clinically significant gastrointestinal, renal, hepatic, neurologic, hematologic, endocrine, oncologic, pulmonary, immunologic, psychiatric, or cardiovascular/ischemic disease or any other condition that, in the opinion of the investigator would jeopardize the safety of the participant or impact the validity of the study results
  • Any clinically significant medical or psychiatric condition or medical history that, in the opinion of the investigator or the medical monitor, would interfere with the participant's ability to participate in the study or increase the risk of participation for that participant
  • Current participation in any other investigational study with an investigational product or participation within 30 days prior to the start of the Screening Period or 5 half-lives of the previously taken investigational drug, whichever is longer
  • Participant has previously received PTC857
  • Participant is receiving a combination of edaravone and sodium phenylbutyrate/taurursodiol treatment, where applicable, within 30 days prior to the start of the Screening Period
  • For female participants, any past medical history of breast cancer, regardless of remission status, or any first degree relative with history of breast cancer


  • UC Irvine Health ALS and Neuromuscular Center accepting new patients
    Orange California 92868 United States
  • Forbes Norris MDA/ALS Research Center at California Pacific Medical Center accepting new patients
    San Francisco California 94109 United States


accepting new patients
Start Date
Completion Date
PTC Therapeutics
Phase 2 Amyotropic Lateral Sclerosis (ALS) Research Study
Study Type
Expecting 258 study participants
Last Updated