Patient-individualized Peptide Vaccination Based on Tumor-specific Mutations in Children and Young Adults With Primary/Relapsed ALL

Prospective Phase I/II Study: Patient-individualized Peptide Vaccination Based on Whole Exome Sequencing With Adjuvant GM-CSF (Granulocyte Macrophage Colony-stimulating Factor) in Children and Young Adults With Primary/Relapsed Acute Lymphoblastic Leukemia

The aim of this clinical study is to evaluate the feasibility and safety of an individualized peptide vaccination approach in patients with acute lymphoblastic leukemia (ALL). For this purpose, tumor-specific mutations are analyzed by comparative exome sequencing of tumor and healthy reference tissue. Expression of variants is further validated by RNA sequencing. In a second step, HLA-binding (human leukocyte antigen-binding) peptides derived from mutated protein sequences are selected for vaccination. The peptides are administered as a vaccination cocktail with adjuvant GM-CSF and Imiquimod over a course of 9 months and a total of 16 vaccinations. Primary objective is the de novo induction of a specific T cell response without unacceptable toxicity and acute GvHD (graft versus host disease).

Inclusion Criteria:

• Pediatric patients and young adults with ALL (T, B, pro-B, pre-B or c-ALL) ≥CR3 or with ≥1st relapse after stem cell transplantation (SCT); or patients in ≤CR2 who have received SCT without having reached a sufficient molecular remission prior to, or after SCT (defined as MRD ≥10^-4); or patients with initially refractory disease to standard treatment who could proceed to stem cell transplantation with alternative treatment options.
• Hematological remission has to be reached (<5% blasts in bone marrow or detectable minimal residual disease (MRD) ≤5x10^-2) after salvage chemotherapy and/or subsequent SCT.

Exclusion Criteria:

• Frank relapse (>5% leukemic blasts).
• Ejection fraction <25%; Creatinine-clearance <40ml/min; Bilirubin >4mg/dl, Transaminases >400 units/ml; severe infection (HIV, Hepatitis), acute GvHD III-IV or chronic GvHD.
• Significant psychiatric disabilities, uncontrolled seizure disorders or severe peripheral neuropathy/ leukoencephalopathy.
• Signs of autoimmune disease (i.e. idiopathic thrombocytopenic purpura, autoimmune hemolytic anemia).
• Need for immunosuppressive drugs.
• No tumor material available for exome sequencing.