Pridopidine EAP2

Inclusion Criteria Amyotrophic Lateral Sclerosis (ALS):
*  Sporadic or familial ALS.
*  Patient does not qualify for clinical trials of pridopidine or as per site investigator's opinion, and is not medically or geographically suitable for other clinical trials.
*  Capable of providing informed consent and complying with study procedures, in the site investigator's opinion.
*  Patient has established care with a physician at a specialized ALS center involved in the study and will maintain this clinical care throughout the duration of the EAP.
*  Pridopidine naive patients must have a life expectancy of at least 6 months in the site investigator's opinion. Inclusion Criteria Huntington Disease (HD):
*  Participation is by invitation, limited to individuals completing clinical study PL101-HD301 (PROOF-HD), OR
*  Confirmed diagnosis of HD, defined as:
*  Clinical features and the presence of ≥36 cytosine-adenine-guanine (CAG) repeats in the Huntington gene (HTT), and confirmed by historical laboratory quantified results or by a diagnostic test prior to the initial dose, and
*  Diagnostic confidence level (DCL) of at least 3 unequivocal motor signs (≥90% confidence) on the standardized motor examination Unified Huntington Disease Rating Scale - Total Motor Score (UHDRS-TMS), and
*  Stage 1 or Stage 2 HD, defined as a UHDRS-Total Functional Capacity (TFC) score of ≥7 prior to the initial dose. Exclusion Criteria ALS:
*  Confirmed prolonged Fridericia-corrected QT (QTcF) interval (\>450 ms for men; \>470 ms for women).
*  Clinically significant heart disease, clinically significant history of arrhythmia, symptomatic or uncontrolled atrial fibrillation despite treatment, asymptomatic sustained ventricular tachycardia, or left bundle branch block.
*  Known history of long QT syndrome or a first degree relative with long QT syndrome.
*  Use of prohibited medications within the 4 weeks prior to baseline.
*  Use of Nuedexta (\>20 mg dextromethorphan and \>10 mg quinidine twice daily); citalopram \>20 mg/day; escitalopram \>10 mg/day.
*  Known allergy to pridopidine or any of the exipients (silicified microcrystalline cellulose, magnesium stearate).
*  History of any clinically significant or unstable medical condition or laboratory abnormality that, based on site investigator's judgment, may interfere with assessment of the study objectives.
*  Female who is pregnant or nursing or who plans to get pregnant during the course of the EAP.
*  Female of child-bearing potential or male unwilling or unable to use accepted methods of birth control.
*  Use of investigational treatments for ALS (as part of participation in a clinical trial or another EAP) within 5 half-lives (if known) or 30 days (whichever is longer) prior to screening (other than pridopidine).
*  Patient receives or has received any gene or cell-based therapy.
*  Active cancer or history of cancer, except for basal cell carcinoma or successfully treated squamous cell carcinoma of the skin, cervical carcinoma in situ, prostatic carcinoma in situ, or other malignancies curatively treated and with no evidence of disease recurrence for at least 3 years.
*  Patients who chose to take experimental medications and/or supplements, and for whom this is the only reason they are not eligible for trials. Exclusion Criteria HD:
*  Early withdrawal from study PL101-HD301 (PROOF-HD) in either double-blind or open label extension phase.
*  Pregnant or breastfeeding, or intention to become pregnant during post-trial access (PTA) treatment.
*  Male patient with a female partner planning to become pregnant during PTA treatment.