Phase I trial of a novel DNA vaccine in patients (pts) with smoldering Waldenstrom macroglobulinemia (sWM)

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Background: Idiotypic determinants of the surface immunoglobulin (Ig) associated with a given pt’s B-cell lymphoma are unique to that tumor, and thus are a tumor-specific marker. This study aims to use an idiotype DNA vaccine to lengthen the smoldering phase of WM without inducing cross-resistance to available therapies. Administered vaccine used recombinant plasmid DNA encoding a fusion protein, consisting of autologous lymphoma scFv (pt-specific idiotype) and human CCL20 (macrophage inflammatory protein-3 alpha - MIP-3α) chemokine. Targeted delivery of this fusion protein to APCs, and subsequent processing and presentation, is hypothesized to break tolerance and generate an immune response against the idiotype, promoting eradication of antigen-expressing B-cell lymphoma cells. Methods: Pts with sWM received 3 i.d. vaccinations of pt-specific DNA vaccine at 4-week (wk) intervals (wks 0, 4 and 8). Two dose levels (500µg; 2500µg) were evaluated in a 3+3 design. Primary objective: to evaluate the vaccine’s safety and identify it’s MTD. Secondary objectives: 1) to assess immunogenicity of the vaccine 2) to determine time to symptomatic WM. Results: Between 1/2016 - 1/2019, 9 pts (7 men) were treated (500 µg: n = 3; 2500µg: n = 6). Median age at enrollment was 67 yrs (range 56-78); median time from diagnosis to 1st vaccination was 26.5 mos (8.8-120.9). MYD88 L265P + (6 pts). CXCR4 WHIM + (1 pt). With median follow up of 26.5 months (range: 8-36.4), all pts remain alive. Seven have stable disease; 2 progressed to symptomatic WM (8 mos. (1pt) and 26 mos. (1pt) from 1st vaccination). All pts completed planned therapy. No DLTs or Grade 4 AEs occurred. Ten mos. after the 3rd vaccination, 1 pt had a grade 3 pleural effusion and leukopenia with an increase in rheumatoid factor (23.1 IU/mL [normal range 0.0-15.9]) and ANA titer of 1:80; all resolved within 2 mos. Grade 1-2 AEs ( > 3pts): leukopenia (6), nausea (5), anemia (4), increased creatinine (4), fatigue (4). Conclusions: Idiotype (scFv-CCL20) DNA vaccine therapy appears to be safe in pts with sWM. Results of immunogenicity assays are underway, and will inform whether tumor specific immune responses are induced. Additional follow up is required to determine time to symptomatic WM. Clinical trial information: NCT01209871.

Phase I study of an active immunotherapy for asymptomatic phase Lymphoplasmacytic lymphoma with DNA vaccines encoding antigen-chemokine fusion: study protocol

BACKGROUND

There is now a renewed interest in cancer vaccines. Patients responding to immune checkpoint blockade usually bear tumors that are heavily infiltrated by T cells and express a high load of neoantigens, indicating that the immune system is involved in the therapeutic effect of these agents; this finding strongly supports the use of cancer vaccine strategies. Lymphoplasmacytic lymphoma (LPL) is a low grade, incurable disease featuring an abnormal proliferation of Immunoglobulin (Ig)-producing malignant cells. Asymptomatic patients are currently managed by a "watchful waiting" approach, as available therapies provide no survival advantage if started before symptoms develop. Idiotypic determinants of a lymphoma surface Ig, formed by the interaction of the variable regions of heavy and light chains, can be used as a tumor-specific marker and effective vaccination using idiotypes was demonstrated in a positive controlled phase III trial.

METHODS

These variable region genes can be cloned and used as a DNA vaccine, a delivery system holding tremendous potential for streamlining vaccine production. To increase vaccination potency, we are targeting antigen-presenting cells (APCs) by fusing the antigen with a sequence encoding a chemokine (MIP-3α), which binds an endocytic surface receptor on APCs. Asymptomatic phase LPL is an excellent model to test our vaccine since patients have not received chemotherapeutics that interfere with innate immune function and have low tumor burden. We are evaluating the safety of this next-generation DNA vaccine in a first-in-human clinical trial currently enrolling asymptomatic LPL patients. To elucidate the mode of action of this vaccine, we will assess its ability to generate tumor-specific immune responses and examine changes in the immune profile of both the peripheral blood and bone marrow.

DISCUSSION

This vaccine could shift the current paradigm of clinical management for patients with asymptomatic LPL and inform development of other personalized approaches.

TRIAL REGISTRATION

ClinicalTrials.gov identifier NCT01209871; registered on September 24, 2010.

Abstract 2891: Bench-to-bedside development of a novel idiotype vaccine against lymphoma

Available therapies for lymphoplasmacytic lymphoma (LPL) provide no survival advantage if started before symptoms of end organ damage develop. Current recommendations are to follow a program of observation while patients are in the asymptomatic phase of disease. In this clinical study we will use idiotypic determinants of B-cell lymphoma surface immunoglobulins as tumor-specific antigens (idiotype) to develop a patient-specific vaccine against LPL. By activating the host immune system through vaccination to eradicate tumor cells, we postulate that disease control of asymptomatic phase lymphoplasmacytic lymphoma can be maintained. This novel 2nd generation idiotype vaccine was initially developed by genetic fusion of idiotype antigen in single-chain format with a pro-inflammatory chemokine. The central hypothesis is that antitumor immunity can be triggered by targeting antigen delivery to antigen-presenting cells in vivo by chemokine receptor-mediated binding, uptake and processing of idiotype antigens for more efficient presentation to T cells. A large body of preclinical data demonstrated that the immunogenecity of the idiotype antigen was considerably enhanced by such a genetic modification by a mechanism of facilitating antigen presentation. As a consequence, vaccine-induced prophylactic and therapeutic antitumor effects were significantly potentiated. To translate our vaccine therapy from bench to bedside, we established a CLP laboratory for vaccine preparation. Furthermore, we developed reliable technology to differentiate lymphoma idiotype antigens from idiotypic cell-surface immunoglobulins on normal B cells. Using this technology, we successfully cloned the cDNA encoding variable regions of heavy and light chains of LPL idiotype, and generated patient-specific plasmid constructs containing LPL idiotype single chain in fusion with macrophage inflammatory protein 3 alpha (MIP3a). All three engineering rounds of down-stream GMP amplification of clinical-grade plasmid DNA have been accomplished, which eventually paves the way for us to take a lab-grown agent to a first-in-human clinical trial.

Citation Format: Hong Qin, Soungchul Cha, Sheetal S. Rao, Kunhwa Kim, Dongho Gwak, Sung-doo Kim, Sapna R. Parshottam, Sheeba K. Thomas, Larry W. Kwak. Bench-to-bedside development of a novel idiotype vaccine against lymphoma. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 2891. doi:10.1158/1538-7445.AM2014-2891