The study is in two parts: a dose escalation then a safety dose expansion. The purpose of the dose escalation part is to evaluate the safety and tolerability of ascending doses of UCART19 (dose-escalation part) given as a single infusion in patients with relapsed / refractory (R/R) B-cell acute lymphoblastic leukaemia (B-ALL), to determine the maximum tolerated dose (MTD), the recommended dose and the lymphodepletion regimen. The purpose of the safety dose expansion is to assess the safety and tolerability of the RD for UCART19.

Inclusion Criteria:

• Male or female participant
• Age ≥ 16 years
• Patient with relapsed or refractory CD19 positive B-acute lymphoblastic leukaemia (B-ALL) who have exhausted alternative treatment options
• Estimated life expectancy ≥ 12 weeks (according to investigator's judgement)
• Eastern Cooperative Oncology Group (ECOG) performance status < 2

Exclusion Criteria:

• Previous treatment with gene or gene-modified cell therapy medicine products or adoptive T cell therapy
• Use of previous anti-leukemic therapy (including approved therapies and other investigational products) within 5 half-lives prior to UCART19 administration
• CD19 negative B-cell leukaemia
• Burkitt cell or mixed lineage acute leukaemia

Qualified scientific and medical researchers can request access to anonymized patient-level and study-level clinical trial data.

Access can be requested for all interventional clinical studies:

• used for Marketing Authorization (MA) of medicines and new indications approved after 1 January 2014 in the European Economic Area (EEA) or the United States (US).
• where Servier is the Marketing Authorization Holder (MAH). The date of the first MA of the new medicine (or the new indication) in one of the EEA Member States will be considered for this scope.

In addition, access can be requested for all interventional clinical studies in patients:

• sponsored by Servier
• with a first patient enrolled as of 1 January 2004 onwards
• for New Chemical Entity or New Biological Entity (new pharmaceutical form excluded) for which development has been terminated before any Marketing authorization (MA) approval.

After Marketing Authorisation in EEA or US if the study is used for the approval.

Researchers should register on Servier Data Portal and fill in the research proposal form. This form in four parts should be fully documented. The Research Proposal Form will not be reviewed until all mandatory fields are completed.