A Phase 1/2 interventional study of ALLO-501A and ALLO-647 in Relapsed or Refractory Large B Cell Lymphoma, Relapsed or Refractory Chronic Lymphocytic Leukemia, Relapsed or Refractory Small Lymphocytic Lymphoma, sponsored by Allogene Therapeutics. Active, not recruiting at 29 sites in 3 countries. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-03-04.
Sponsored by Allogene Therapeutics · Phase 1/2, Interventional, and Treatment
This is a single-arm, open label, multicenter Phase 1/2 study evaluating ALLO-501A in adult subjects with R/R LBCL and CLL/SLL. The purpose of the ALPHA2 study is to assess the safety, efficacy, and cell kinetics of ALLO-501A in adults with relapsed or refractory large B-cell lymphoma and assess the safety of ALLO-501A in adults with relapsed or refractory chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL) after a lymphodepletion regimen comprising fludarabine, cyclophosphamide, and ALLO-647.
2,036 studies on the registry are indexed under Leukemia, Lymphocytic, Chronic, B-Cell; 237 are open to participants now.
This study's planned enrollment of 160 is above the median of 39 across 1,603 interventional studies indexed under Leukemia, Lymphocytic, Chronic, B-Cell.
Browse Leukemia, Lymphocytic, Chronic, B-Cell studies →Allogene Therapeutics is the lead sponsor of 9 studies on the registry; 3 are open to participants now.
Compared within Leukemia, Lymphocytic, Chronic, B-Cell, this study's primary condition as ClinicalTrials.gg classifies it; the registry's first condition term is Recurrence. The counts are of registry records indexed under each term, refreshed daily. How we classify →
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
For subjects with LBCL:
For subjects with CLL/SLL:
For all subjects:
Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
The diagnosis was confirmed by looking at a sample under a microscope: tissue from a biopsy or surgery (histology), or cells from a fluid or needle sample (cytology).
Your pathology report is the document that shows this.
Relapsed: the illness came back after treatment had worked. Refractory: it did not respond to treatment, or stopped responding while still on it.
The amount of disease can be tracked with a defined measurement, so the study can see whether it shrinks or grows. It might be a tumour measured on a scan or, in some blood cancers such as myeloma, a marker measured in blood or urine.
The criteria or the study team say which measurement counts — having no tumour visible on a scan does not by itself rule you out.
A line of therapy is one course of treatment, which may combine several drugs. First-line is the first course given; second-line follows when that stops working or is not tolerated.
“Two prior lines” means two courses that count separately under the study’s rules — not simply two drugs. Ask the study team if you are unsure how yours are counted.
A scale of how much an illness limits everyday activity. For people being assessed to join a study, scores run from 0 (fully active) to 4; lower is more active.
Studies most often ask for 0–1 or 0–2. Your doctor gives the score; the WHO scale uses the same steps. The full scale also has 5, which records death.
Malignancy means cancer. Criteria about another or earlier malignancy ask whether you have had a different cancer, usually within a set number of years.
Some are commonly allowed, such as treated skin cancers other than melanoma and early cancers removed completely — check the exceptions this study lists.
A biopsy takes a small piece of tissue to examine. “Archival tissue” is a sample already taken, for example at diagnosis, and kept by the hospital.
Whether a stored sample will do depends on when it was taken, how much there is and what the study needs. Ask whether the study accepts your stored sample or needs a new biopsy.
Stem cell (bone marrow) transplants. Allogeneic uses cells from a donor; autologous uses your own cells, collected earlier and given back.
Histologically or cytologically confirmed
The diagnosis was confirmed by looking at a sample under a microscope: tissue from a biopsy or surgery (histology), or cells from a fluid or needle sample (cytology).
Your pathology report is the document that shows this.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Relapsed and refractory
Relapsed: the illness came back after treatment had worked. Refractory: it did not respond to treatment, or stopped responding while still on it.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Measurable disease
The amount of disease can be tracked with a defined measurement, so the study can see whether it shrinks or grows. It might be a tumour measured on a scan or, in some blood cancers such as myeloma, a marker measured in blood or urine.
The criteria or the study team say which measurement counts — having no tumour visible on a scan does not by itself rule you out.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Line of therapy
A line of therapy is one course of treatment, which may combine several drugs. First-line is the first course given; second-line follows when that stops working or is not tolerated.
“Two prior lines” means two courses that count separately under the study’s rules — not simply two drugs. Ask the study team if you are unsure how yours are counted.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
ECOG performance status
A scale of how much an illness limits everyday activity. For people being assessed to join a study, scores run from 0 (fully active) to 4; lower is more active.
Studies most often ask for 0–1 or 0–2. Your doctor gives the score; the WHO scale uses the same steps. The full scale also has 5, which records death.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Cancer (malignancy)
Malignancy means cancer. Criteria about another or earlier malignancy ask whether you have had a different cancer, usually within a set number of years.
Some are commonly allowed, such as treated skin cancers other than melanoma and early cancers removed completely — check the exceptions this study lists.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Biopsy and archival tissue
A biopsy takes a small piece of tissue to examine. “Archival tissue” is a sample already taken, for example at diagnosis, and kept by the hospital.
Whether a stored sample will do depends on when it was taken, how much there is and what the study needs. Ask whether the study accepts your stored sample or needs a new biopsy.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Allogeneic and autologous transplant
Stem cell (bone marrow) transplants. Allogeneic uses cells from a donor; autologous uses your own cells, collected earlier and given back.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Genetic: ALLO-501A · Biological: ALLO-647 · Drug: Fludarabine · Drug: Cyclophosphamide
ALLO-501A is an allogeneic CAR T cell therapy targeting CD19
ALLO-647 is a monoclonal antibody that recognizes a CD52 antigen
Chemotherapy for lymphodepletion
Chemotherapy for lymphodepletion
Phase 1a: Proportion of subjects experiencing Dose Limiting Toxicities (DLT) at increasing doses of ALLO-501A
Dose limiting toxicity is defined as protocol-defined ALLO-501A-related adverse events with onset within 28 days following infusion
Time frame: 28 days
Phase 1a: Proportion of subjects experiencing Dose Limiting Toxicity with ALLO-647 in combination with fludarabine/cyclophosphamide administered prior to ALLO-501A
DLT is defined as protocol-defined ALLO-647-related adverse events with onset within 33 days following 1st infusion
Time frame: 33 days
Phase 1b: Frequency and severity of ALLO-501A treatment-emergent adverse events (AEs), serious AEs, and AEs of special interest
Time frame: Up to 60 months
Phase 2: Overall Response Rate (ORR) assessed per Independent Review Committee (IRC)
ORR defined as assessment of CR and PR using Lugano classification criteria 2014
Time frame: Up to 60 months
Phase 1a, 1b, and 2: Duration of Response (DOR) assessed per IRC (Phase 2 only) and per investigator
DOR is defined only for subjects who experience an objective response and is the time from the first objective response to disease progression or death, whichever comes first per (Cheson et al, 2014)
Time frame: Up to 60 months
Phase 1a, 1b, and 2: Overall Response Rate (ORR) assessed per investigator
Time frame: Up to 60 months
Phase 1a, 1b, and 2: Best overall response (CR, PR, SD, PD) assessed per IRC (Phase 2 only) and per investigator
CR Complete Response, PR Partial Response, SD Stable Disease, PD Progressive Disease
Time frame: Up to 60 months
Phase 1a, 1b, and 2: Progression Free Survival (PFS) assessed per IRC (Phase 2 only) and per investigator
PFS, defined as time from the enrollment date to progression, relapse, or death
Time frame: Up to 60 months
Phase 1a, 1b, and 2: Time to Response (TTR) assessed per IRC (Phase 2 only) and per investigator
TTR, defined as the time from the enrollment date to the first observed response
Time frame: Up to 60 months
Phase 1a, 1b, and 2: Overall Survival (OS)
OS, defined as the time from the enrollment date to death
Time frame: Up to 60 months
Phase 1a, 1b, and 2: Depth of lymphodepletion as assessed by lymphocyte count
Time frame: Up to 9 months
Phase 1a, 1b, and 2: Duration of lymphodepletion as assessed by lymphocyte recovery
Time frame: Up to 9 months
Phase 1a, 1b, and 2: Serum concentration of ALLO-647 as measured by microgram per microliter for use in a population PK model
Time frame: Up to 9 months
Phase 1a, 1b, and 2: ALLO-501A expansion assessed by peak blood concentration (Cmax)
Time frame: Up to 9 months
Phase 1a, 1b, and 2: ALLO-501A expansion assessed by area under the curve (AUC)
Time frame: Up to 9 months
Phase 1a, 1b, and 2: ALLO-501A persistence assessed by peak blood concentration (Cmax)
Time frame: Up to 9 months
Phase 1a, 1b, and 2: ALLO-501A persistence assessed by area under the curve (AUC)
Time frame: Up to 9 months
Phase 1a, 1b, and 2: Pharmacodynamics will be evaluated on host T cell counts
Time frame: Up to 9 months
Phase 1a, 1b, and 2: The incidence of anti-drug antibodies against ALLO-501A scFv and/or TALEN®
Time frame: Up to 9 months
Phase 1a, 1b, and 2: The incidence of anti-drug antibodies against ALLO-647
Time frame: Up to 9 months
Phase 1a, 1b, and 2: Adverse Events (AEs) as characterized by preferred term, frequency, severity timing, seriousness, and relationship to ALLO-501A
The incidence and severity of Cytokine Release Syndrome (CRS), Graft-Versus-Host Disease (GVHD), infections, cytopenias, and neurotoxicity
Time frame: Up to 60 months
Phase 1a, 1b, and 2: AEs as characterized by preferred term, frequency, severity, timing, seriousness, and relationship to ALLO-647
The incidence of infusion-related reactions, cytopenias, and infections
Time frame: Up to 60 months
Phase 1a, 1b, and 2: The incidence and severity of clinically significant laboratory toxicities and relationship to ALLO-647
Time frame: Up to 60 months
Started May 2020 (actual). Primary completion is estimated for Feb 2029, 105 months after the start.
Of 50 industry-sponsored phase 1/2 interventional studies under Leukemia, Lymphocytic, Chronic, B-Cell, half reached primary completion within 80 months of starting (the median), counting those still running; a quarter within 51 and three quarters within 104. This study's planned 105 months is above that.
Counting every sponsor, half of 90 studies reached it within 78 months; a quarter within 51 and three quarters within 103.
How these figures are worked out, and which studies are left out of them.
This study is active, not recruiting, as verified in Mar 2026. You cannot join it, but the record below documents what was studied.
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Studies of the drug tested here: Anti-CD52 Monoclonal Antibody ALLO-647
Leukemia, Lymphocytic, Chronic, B-Cell →
Allogene Therapeutics