RAPA-501 Therapy for ALS

Phase 2/3 Trial of Autologous Hybrid TREG/Th2 (RAPA-501) T Stem Cell Therapy for Amyotrophic Lateral Sclerosis

RAPA-501 Therapy for ALS (NCT04220190) is a Phase 2 / Phase 3 interventional studying Amyotrophic Lateral Sclerosis, sponsored by Rapa Therapeutics LLC. RECRUITING as of the most recent ClinicalTrials.gov update. Talk to your doctor before contacting the trial site.

About This Trial

RAPA-501-ALS is a phase 2/3 expansion cohort study of RAPA-501 autologous hybrid TREG/Th2 cells in patients living with amyotrophic lateral sclerosis (pwALS).

What Stage of Research Is This?

Phase 2 trials evaluate whether a treatment actually works against Amyotrophic Lateral Sclerosis and continue monitoring side effects. Phase 2 enrolls larger groups (typically 100–300 patients) and produces the first real efficacy signal. A successful Phase 2 readout is what unlocks the much larger Phase 3 confirmatory trials needed for FDA approval.

This trial is currently recruiting participants. The sponsor has registered the study with ClinicalTrials.gov as actively enrolling, which means new applicants who meet the eligibility criteria can be considered for screening. Trial status can change between updates — confirm current recruiting status with the study contact before traveling for a screening visit.

With a target enrollment of 41 participants, this is a small study — typical of early-phase research, rare-disease trials, or pilot studies designed to generate preliminary signal before a larger study is launched.

Who May Be Eligible (Plain English)

Who May Qualify: 1. Male or female patients ≥ 18 years of age. 2. Patients with sporadic or familial amyotrophic lateral sclerosis (ALS) diagnosed as laboratory-supported possible, probable, or definite according to World Federation of Neurology El Escorial Criteria. 3. . Less than or equal to 24 months since ALS symptom onset. 4. Total ALSFRS-R score between 34 and 45. 5. Must have a source of autologous T cells potentially sufficient to manufacture RAPA-501 cells, as defined by a peripheral CD3+ T cell count ≥ 500 cells per μl. 6. Patients may continue riluzole (Rilutek®), and/or edaravone (Radicava®), and/or sodium phenylbutyrate/taurusodial (Relyvrio™) if on a stable dose for at least 30 days prior to the screening visit. 7. Patients must be ≥ 2 two weeks removed from major surgery or investigational therapy. 8. Patients must have recovered from clinical toxicities (\[resolution of CTCAE(v5) \[version 5\] toxicity to a value of ≤ 2\].). 9. Serum creatinine ≤ less than or equal to 2.0 mg/dL. 10. Aspartate aminotransferase (AST) and alanine aminotransferase (ALT) ≤ 3 x upper limit of normal (ULN). 11. Bilirubin ≤ 1.5 (except if due to Gilbert's disease). 12. Pulmonary slow vital capacity (SVC) ≥ 70% of predicted normal. 13. No history of abnormal bleeding tendency. 14. Voluntary written consent must be given before performance of any study related procedure not part of standard medical care, with the understanding that consent may be withdrawn by the patient participant at any time without prejudice to future medical care. Who Should NOT Join This Trial: 1. Active uncontrolled infection. 2. Hypertension not adequately controlled by ≤ 3 medications. 3. History of documented pulmonary embolus within 6 months of enrollment. ...See full criteria on ClinicalTrials.gov Always talk to your doctor about whether this trial is right for you.

These are translations of the protocol\'s inclusion and exclusion criteria, simplified for patients and caregivers. The original clinical text appears below. Eligibility is ultimately confirmed by the trial site\'s screening process — this summary is a starting point for a conversation with your doctor, not a final determination.

Original Eligibility Criteria

View original clinical language

Inclusion Criteria: 1. Male or female patients ≥ 18 years of age. 2. Patients with sporadic or familial amyotrophic lateral sclerosis (ALS) diagnosed as laboratory-supported possible, probable, or definite according to World Federation of Neurology El Escorial Criteria. 3. . Less than or equal to 24 months since ALS symptom onset. 4. Total ALSFRS-R score between 34 and 45. 5. Must have a source of autologous T cells potentially sufficient to manufacture RAPA-501 cells, as defined by a peripheral CD3+ T cell count ≥ 500 cells per μl. 6. Patients may continue riluzole (Rilutek®), and/or edaravone (Radicava®), and/or sodium phenylbutyrate/taurusodial (Relyvrio™) if on a stable dose for at least 30 days prior to the screening visit. 7. Patients must be ≥ 2 two weeks removed from major surgery or investigational therapy. 8. Patients must have recovered from clinical toxicities (\[resolution of CTCAE(v5) \[version 5\] toxicity to a value of ≤ 2\].). 9. Serum creatinine ≤ less than or equal to 2.0 mg/dL. 10. Aspartate aminotransferase (AST) and alanine aminotransferase (ALT) ≤ 3 x upper limit of normal (ULN). 11. Bilirubin ≤ 1.5 (except if due to Gilbert's disease). 12. Pulmonary slow vital capacity (SVC) ≥ 70% of predicted normal. 13. No history of abnormal bleeding tendency. 14. Voluntary written consent must be given before performance of any study related procedure not part of standard medical care, with the understanding that consent may be withdrawn by the patient participant at any time without prejudice to future medical care. Exclusion Criteria: 1. Active uncontrolled infection. 2. Hypertension not adequately controlled by ≤ 3 medications. 3. History of documented pulmonary embolus within 6 months of enrollment. 4. Clinically significant cardiac pathology, as defined by: myocardial infarction within 6 months prior to enrollment, Class III or IV heart failure according to NYHA, uncontrolled angina, severe uncontrolled ventricular arrhythmias, or electrocardiographic evidence of acute ischemia or active conduction system abnormalities. 5. Patients with history of coronary artery bypass grafting or angioplasty will receive a cardiology evaluation and be considered on a case-by-case basis. 6. HIV, hepatitis B, or hepatitis C seropositive. 7. Pregnancy or breastfeeding patients. 8. Patients of Subjects of childbearing age, or males who have a partner of childbearing potential, who are unwilling to practice contraception. 9. Patients Subjects may be excluded at the Principal Investigator discretion of the PI or if it is deemed that allowing participation would represent an unacceptable medical or psychiatric risk.

Treatments Being Tested

BIOLOGICAL

RAPA-501 Autologous T stem cells

Experimental: Phase 2/3 Expansion Cohort, Single-agent RAPA-501 T stem cells 80 x 10EE6 cells per infusion (no host conditioning)

Locations (1)

Trial sites listed on ClinicalTrials.gov for this study. Site activation status can vary — confirm with the specific site before traveling for a screening visit.

Massachusetts General Hospital

Boston, Massachusetts, United States

How to Talk to Your Doctor About This Trial

Bring the printable summary of this trial — including the NCT ID (NCT04220190), the sponsor (Rapa Therapeutics LLC), and the key eligibility criteria — to your next appointment. Your doctor can review the inclusion and exclusion criteria against your medical history, lab values, and current treatments to assess whether you are likely to qualify. They can also help you weigh whether trial participation makes sense alongside your existing care plan.

Useful questions to walk through together: What does the trial protocol require beyond standard care? How long is the active treatment phase, and how long is follow-up? Are there study visits at sites I can reach? Who pays for the trial-specific procedures, and who pays for standard-of-care portions? See our 25 questions to ask about clinical trials guide for a more complete checklist.

Authoritative Sources

The official record for this trial lives on ClinicalTrials.gov — the federal registry maintained by the National Library of Medicine at NIH. For background on how this trial fits into the FDA approval pathway, see the FDA drug approval process. For oncology-specific guidance for patients considering trials, the National Cancer Institute publishes patient-oriented overviews. International trial registries are aggregated by the WHO ICTRP.

Frequently Asked Questions

What is the NCT04220190 clinical trial studying?

RAPA-501-ALS is a phase 2/3 expansion cohort study of RAPA-501 autologous hybrid TREG/Th2 cells in patients living with amyotrophic lateral sclerosis (pwALS). The full protocol is registered on ClinicalTrials.gov and includes the primary outcome measures, eligibility criteria, and study endpoints.

Who can participate in NCT04220190?

Eligibility for this trial depends on the specific inclusion and exclusion criteria set by the sponsor. The plain-English summary above translates the most important criteria into accessible language; the official clinical text is preserved in the collapsible section underneath. Whether you fit any specific trial is a medical decision your doctor needs to confirm — bring the trial information to your treating physician for a full review against your medical history.

How do I contact the trial site for NCT04220190?

Contact information registered with ClinicalTrials.gov is shown in the sidebar of this page. Before reaching out, confirm with your treating physician that this trial is appropriate for your situation. The trial site will then walk you through the screening process to determine final eligibility.

Is participating in a clinical trial safe?

Clinical trials in the United States are regulated by the FDA and overseen by Institutional Review Boards (IRBs) that review the protocol for safety. Risk varies by trial — Phase 1 studies test new treatments in humans for the first time, while Phase 3 trials use treatments that have already passed earlier safety screening. The informed consent document for any specific trial details the known risks and what to expect. Discuss those risks with your physician before deciding whether to participate.

Where can I verify the data on this page?

Every detail on this page comes directly from the ClinicalTrials.gov API. Click "View on ClinicalTrials.gov" in the sidebar to see the official, unmodified record. The federal record is always authoritative; this page is a structured presentation with a plain-English eligibility translation. For background on how clinical trials are regulated, see the FDA drug approval process documentation.

How This Page Is Built

Every field on this page is pulled directly from the ClinicalTrials.gov API v2 — no estimates, no proxies. The plain-English eligibility translation is generated from the original protocol text and reviewed for fidelity to the underlying clinical criteria. The original clinical text remains visible in the collapsible section above so users and clinicians can verify the translation. Read the full methodology for the data pipeline and known limitations.

Source: ClinicalTrials.gov API v2 record for NCT04220190. Maintained by the National Library of Medicine at NIH. Public domain. Cite as: "TrialFinderData. NCT04220190. Data: ClinicalTrials.gov."

Medical disclaimer: This page is informational, not medical advice. Talk to your doctor about whether a clinical trial is right for you.

Last updated 2026-05-08 · Data from ClinicalTrials.gov.