Tumor-specific recombinant idiotype immunisation after chemotherapy as initial treatment for follicular non-Hodgkin lymphoma

Abstract

Tumor-specific variable regions of the clonal immunoglobulin (idiotype, Id) expressed by B cell non-Hodgkin lymphoma (NHL) can be targeted by active immunotherapy. We conducted a phase I/II trial to determine the safety and immunogenicity of a patient-specific, recombinant, mammalian cell-derived Id protein conjugated to keyhole limpet hemocyanin (Id-KLH; MyVax personalised immunotherapy) in 22 patients with follicular NHL in first remission after chemotherapy. Subjects received five subcutaneous immunisations with MyVax plus locally administered granulocyte-macrophage colony-stimulating factor (GM-CSF). Among 21 evaluable patients, 62% mounted Id-specific immune responses. Evoked anti-Id antibodies recognised both recombinant Id and native Id, and could specifically stain autologous tumor cells. At median follow-up of more than 6 years, median progression-free survival is 38 months. Immunisation of follicular lymphoma patients with MyVax Id-KLH is safe and patients often mount tumor-specific immune responses. These results form the basis of a pivotal phase 3 trial of MyVax in follicular NHL.

Figures

Figure 1

Therapeutic immunisation for lymphoma with recombinant idiotype protein. (A) Schema for production and administration of MyVax®. PCR, polymerase chain reaction; Id, idiotype; VH and VL, heavy and light chain variable regions; KLH, keyhole limpet hemocyanin. (B) Treatment schedule for cytoreductive chemotherapy and immunisations.

Figure 2

Idiotype-specific immune responses following Id-KLH immunisation. (A) Patient 5 humoral response measured by ELISA. Pre- or post-vaccination serum was serially diluted and tested for binding (indicated by optical density, O.D.) to the patient's own tumor Id vs. another patient's (irrelevant) Id protein as a control. Only post-vaccine serum shows a high degree of tumor Id-specific binding. (B) Specificity of an anti-Id antibody response after immunisation. Post-immunisation sera (patient 1) was serially diluted and tested by ELISA for binding (indicated by optical density, O.D.) to the patient's own tumor (relevant) Id versus three other patient's tumor Id proteins as controls. The solid black line indicates a highly tumor-specific antibody response, with minimal binding to other patient's tumor Ids (irrelevant; dashed lines). (C) Flow cytometric demonstration that anti-Id antibodies induced by recombinant Id-KLH vaccine specifically recognise autologous tumor cells. Tumor cells from patients 2 and 5 (upper and lower sets of panels, respectively) were incubated with either autologous post-vaccine serum or that of the other patient as a control. Bound anti-Id IgG antibodies were detected by anti-IgG-PE (Y-axis), and tumor B cells (IgM+) were counterstained by anti-IgM-FITC (X-axis). Each patient's serum specifically recognises only the autologous tumor cells, but not the control, irrelevant tumor cells. (D) Tumor Id-specific T cell proliferative response post-vaccination. Proliferation of PBMC cultured with autologous tumor Id or irrelevant control Id proteins (100 μg/mL) from other patient's tumors were measured by 3H-thymidine incorporation (counts per minute, c.p.m.). The kinetics of the T cell proliferative response to tumor versus control Id proteins during the course of the five immunisations is depicted. Maximal T cell response is achieved after the 5th injection.

Figure 3

Progression-free survival (PFS) of all 21 evaluable subjects, measured from the date of last chemotherapy. Nine of 21 subjects (43%) remain in remission after median of follow-up of 77 months. Median PFS is 38 months.