Plant-produced idiotype vaccines for the treatment of non-Hodgkin's lymphoma: Safety and immunogenicity in a phase I clinical study

Abstract

Plant-made vaccines have been the subject of intense interest because they can be produced economically in large scale without the use of animal-derived components. Plant-made therapeutic vaccines against challenging chronic diseases, such as cancer, have received little research attention, and no previous human clinical trials have been conducted in this vaccine category. We document the feasibility of using a plant viral expression system to produce personalized (patient-specific) recombinant idiotype vaccines against follicular B cell lymphoma and the results of administering these vaccines to lymphoma patients in a phase I safety and immunogenicity clinical trial. The system allowed rapid production and recovery of idiotypic single-chain antibodies (scFv) derived from each patient's tumor and immunization of patients with their own individual therapeutic antigen. Both low and high doses of vaccines, administered alone or co-administered with the adjuvant GM-CSF, were well tolerated with no serious adverse events. A majority (>70%) of the patients developed cellular or humoral immune responses, and 47% of the patients developed antigenspecific responses. Because 15 of 16 vaccines were glycosylated in plants, this study also shows that variation in patterns of antigen glycosylation do not impair the immunogenicity or affect the safety of the vaccines. Collectively, these findings support the conclusion that plant-produced idiotype vaccines are feasible to produce, safe to administer, and a viable option for idiotypespecific immune therapy in follicular lymphoma patients.phase I clinical trial ͉ plant-made pharmaceutical ͉ single-chain antibodies I n recent years, non-Hodgkin's lymphoma (NHL) has become the most common hematologic malignancy in the United States with an estimated 54,000 new cases each year. Approximately 30% of these cases are follicular B cell lymphoma (1), with a median survival of 8-10 years from diagnosis (2). Most patients subjected to standard treatments, such as chemotherapy, radiation, or antibodies (2-9), still relapse (10-12). Newer approaches have focused on active immunotherapy through vaccination. For B cell lymphoma, the cell-surface Ig (Ig), or idiotype, is the unique tumorspecific antigen. In contrast to passive therapy, an idiotype-induced immune response is (i) highly tumor specific, thus sparing normal cells; (ii) potentially more durable; and (iii) protective against tumor cell variants that might ''escape'' under selective pressure, because the response is polyclonal (13-15).There exists a 20-year history of idiotype vaccination for follicular lymphoma in animal models and clinical trials. The original vaccine manufacturing process, still used today in the majority of clinical research, used a patient's lymphoma B cells to derive a mouse/ human heteromyeloma cell line for production of the tumor's monoclonal idiotype (16). Once purified, the idiotype antibody was chemically coupled to a highly immunogenic carrier protein, keyhole limpet haemocyanin (KLH), and administered w...

Monoclonal antibody produced in plants efficiently treats West Nile virus infection in mice

“…Whereas plant-derived mAbs or mAb fragments are currently in clinical trials as a cancer vaccine or as topical treatment for tooth decay, and a mAb as postexposure rabies prophylaxis has been reported (23,24), our results demonstrate the efficacy of a plant-produced mAb against a lethal infection several days after exposure. A single dose of pHu-E16 protected mice when administered 2 or 4 days after WNV infection.…”

Transient Virus Expression Systems for Recombinant Protein Expression in Dicot- and Monocotyledonous Plants

“…The majority of the responses was shown to be vaccine specific and did not cross react with control idiotype proteins. These results demonstrated the flexibility of the TMV-based expression systems as well as the safety and effectiveness of the plant derived products [31,51].…”

“…Virus vector expression systems offer significant advantages at considerably reduced costs to current cell-based manufacturing systems, such as employed by Protalix and Dow AgroSciences, while avoiding concerns associated with stable plant transformation [29,30]. Virus based expression systems have been extensively tested and shown safe and environmentally-friendly in both indoor and outdoor tests since 1991 [12] and multiple products completing early stage human clinical investigations [31,32]. Additional advantages also exist compared with traditional cell-based fermentation approaches include: 1) speed and low cost of genetic manipulation; 2) rapid manufacturing cycles; 3) no mammalian pathogen contamination; 4) minimal endotoxin concentrations and 5) economical production [12-15, 33, 34].…”

“…This vaccine strategy was shown to be effective in murine models of NHL [49] and a GENEWARE ® -based production methodology was developed that could produce >80% of scFvs from human tumor samples [50]. Sixteen patients were enrolled in a Phase I clinical trial under the regulatory oversight of the US Food and Drug Administration [31,51]. Vaccines were successfully produced for all patients and applied in two dosing groups with and without granulocyte-macrophage colony-stimulating factor adjuvant.…”

Effect of nitrate concentration in nutrient solution on hemagglutinin content of Nicotiana benthamiana leaves in a viral vector-mediated transient gene expression system

“…Several biopharmaceuticals, such as influenza subunit vaccine antigens and monoclonal antibodies for various infectious diseases, have been produced via viral vector-mediated transient expression systems (Pogue et al 2010;Warzecha 2012). Furthermore, the initial clinical safety and efficacy of such biopharmaceuticals have been confirmed in several reports (Girard et al 2013;McCormick et al 2008;Yusibov et al 2011), demonstrating the feasibility of this emerging technology. A great deal of effort has been devoted to engineering viral vectors to increase expression levels of recombinant PMP proteins (Gleba et al 2007;Matoba et al 2011;Rybicki 2010).…”