Phage idiotype vaccination: first phase I/II clinical trial in patients with multiple myeloma

Abstract

Background: Multiple myeloma is characterized by clonal expansion of B cells producing monoclonal immunoglobulins or fragments thereof, which can be detected in the serum and/or urine and are ideal target antigens for patient-specific immunotherapies.

Methods: Using phage particles as immunological carriers, we employed a novel chemically linked idiotype vaccine in a clinical phase I/II trial including 15 patients with advanced multiple myeloma. Vaccines composed of purified paraproteins linked to phage were manufactured successfully for each patient. Patients received six intradermal immunizations with phage idiotype vaccines in three different dose groups.

Results: Phage idiotype was well tolerated by all study participants. A subset of patients (80% in the middle dose group) displayed a clinical response indicated by decrease or stabilization of paraprotein levels. Patients exhibiting a clinical response to phage vaccines also raised idiotype-specific immunoglobulins. Induction of a cellular immune response was demonstrated by a cytotoxicity assay and delayed type hypersensitivity tests.

Conclusion: We present a simple, time- and cost-efficient phage idiotype vaccination strategy, which represents a safe and feasible patient-specific therapy for patients with advanced multiple myeloma and produced promising anti-tumor activity in a subset of patients.

Figure 1

Clinical response of patients vaccinated with Id-phage. Paraprotein serum levels (black) and light chain excretion (gray) of each individual patient.

Figure 2

Paraprotein changes during treatment and follow up. (A) Maximum absolute paraprotein decrease of each patient. (B) Percental changes of paraproteins during treatment and follow up. (I) Maximum drop of paraprotein levels during treatment; median time after first vaccination: 88 days in the 0.25 mg group (range 6–148 days), 18 days in the 1.25 mg group (range 7–78 days) and 22 days in the 2.5 mg group (range 20–120 days). (II) Paraprotein levels immediately after the last vaccination in relation to paraprotein levels immediately before the first vaccination. (III) Relative paraprotein levels three months after the last vaccination in comparison to paraprotein levels immediately before treatment.

Figure 3

Anti-Id, anti-phage and anti-KLH-specific IgG responses. (A) Id-specific antibody response of patients 7–10 having received 1.25 mg phage Id vaccine. Patients’ sera were obtained shortly before each vaccination (day 1, 7, 14, 28, 56 and 84) and examined by ELISA using anti-Id antibodies. (B) Anti-Id specific immunoglobulin subtypes and anti-phage specific immunoglobulin subtypes (C) in patient 7 at day 28 after immunization with 1.25 mg phage Id vaccine. The results are representative for patients, who had raised and analyzed Id-specific antibodies (patients 7–10). (D) Antibody response to KLH (left) and wild type phage (right). Serum was taken shortly before each vaccination (day 1, 7, 14, week 4, 8, 12). Results of patient 2, having received 0.25 mg phage Id vaccination, are shown.

Figure 4

Cellular anti-tumor response. (A) Cytotoxic T lymphocyte (CTL) response in patient 7. Peripheral blood mononuclear cell cytotoxicity was determined by flow cytometry analysis against bone marrow cells comprising MM cells using an apoptosis detection kit. Target cells were taken from bone marrow biopsy samples from patient 7 before the first vaccination. PBMCs were collected 4 weeks after the first vaccination with 1.25 mg phage Id vaccine. E:T: effector/target cell ratio. (B) Skin biopsy oft the site of phage Id challenge of patient 7. CD8+ (red), but no CD4+ T cell infiltrate was demonstrated.