Inclusion Criteria:

Type of participant and disease characteristics

- Male or female, 18-80 years of age (inclusive)

- Diagnosis of possible, clinically probable ALS, clinically probable 
laboratorysupported ALS, or clinically definite ALS according to the revised version
of the El Escorial World Federation of Neurology criteria

- Time since onset of first symptom of ALS ≤ 2 years.

- Slow Vital Capacity (SVC) ≥ 60% of the predicted value.

- Be able to swallow the study tablets at the screening visit.

- Either not currently receiving riluzole or on a stable dose of riluzole for at least 4
weeks before the screening visit. Participants receiving riluzole are expected to
remain on the same dose throughout the duration of the study.

- Either not currently receiving edaravone or on the approved standard schedule of
edaravone treatment. Participants receiving edaravone must have completed at least 1
cycle of treatment before the screening visit and are expected to continue edaravone
treatment throughout the duration of the study.

Weight : Participants with a body weight no less than 45 kg and body mass index no less
than 18 kg/m^2 .

Female participants with childbearing potential are eligible to participate if they are not
pregnant or breastfeeding and agree to use adequate contraceptive method during study
intervention period and for at least 32 days after the last dose of study drug.

Male participants must agree to use highly effective contraceptive method during the study
period and for at least 92 days following their last dose of the study drug. Male
participants must not donate sperms for the duration of study and 92 days after last dose
of study drug.

Exclusion Criteria:

A history of seizure (History of febrile seizure during childhood is allowed).

Having central IV lines, such as a peripherally inserted central catheter (PICC) or midline
or port a cath lines.

With significant cognitive impairment, psychiatric disease, other neurodegenerative
disorder (eg, Parkinson disease or AD), substance abuse, or any other condition that would
make the participants unsuitable for participating in the study or could interfere with
assessment or completing the study in the opinion of the Investigator.

History of recent serious infection (eg, pneumonia, septicemia) within 4 weeks of the
screening visit; infection requiring hospitalization or treatment with IV antibiotics,
antivirals, or antifungals within 4 weeks of screening; or chronic bacterial infection
(such as tuberculosis) deemed unacceptable as per the Investigator's judgment.

With active herpes zoster infection within 2 months prior to the screening visit.

A documented history of attempted suicide within 6 months prior to the screening visit,
present with suicidal ideation of category 4 or 5 on the Columbia Suicide Severity Rating
Scale (C-SSRS ), or in the Investigator's judgment are at risk for a suicide attempt.

History of unstable or severe cardiac, pulmonary, oncological, hepatic, or renal disease or
another medically significant illness other than ALS precluding their safe participation in
this study.

Participants who are pregnant or are currently breastfeeding.

A known history of allergy to any ingredients of SAR443820.

Prior/concomitant therapy :

- Currently or previously treated with any strong or moderate CYP3A4 inhibitors or
strong CYP3A4 inducers listed in Appendix 10 of the protocol within the specified
washout period before the screening visit.

- Received a live vaccine within 14 days before the screening visit.

Participants with concurrent participation in any other interventional clinical study or
who have received treatment with another investigational drug within 4 weeks or 5 halflives
of the investigational agent before the screening visit, whichever is longer.

Participants who have received stem cell or gene therapy for ALS at any time in the past.

Alanine aminotransferase (ALT) or aspartate aminotransferase (AST ) > 3.0 × upper limit of
normal (ULN )

Bilirubin > 1.5 × ULN unless the participant has documented Gilbert syndrome (isolated
bilirubin > 1.5 × ULN is acceptable if bilirubin is fractionated and direct bilirubin is
< 35%)

Serum albumin < 3.5 g/dL

Estimated glomerular filtration rate < 60 mL/min/1.73 m^2 (Modification of Diet in Renal
Disease [MDRD])

The above information is not intended to contain all considerations relevant to a patient's
potential participation in a clinical trial.