Clinical Cancer Research CTRC-AACR San Antonio Breast Cancer Symposium Translational Cancer Medicine 2008: Cancer Clinical Trials and Personalized Medicine
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
Cancer Research Clinical Cancer Research
Cancer Epidemiology Biomarkers & Prevention Molecular Cancer Therapeutics
Molecular Cancer Research Cancer Prevention Research
Cancer Prevention Journals Portal Cancer Reviews Online
Annual Meeting Education Book Cell Growth & Differentiation
This Article
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Frankel, A. E.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Frankel, A. E.
Clinical Cancer Research Vol. 10, 13-15, January 2004
© 2004 American Association for Cancer Research

The Biology Behind

Reducing the Immune Response to Immunotoxin

Commentary re R. Hassan et al., Pretreatment with Rituximab Does Not Inhibit the Human Immune Response against the Immunogenic Protein LMB-1. Clin. Cancer Res., 10: 16–18, 2004.

Arthur E. Frankel

Department of Medicine, Wake Forest University School of Medicine, Winston-Salem, North Carolina

Immunotoxins are hybrid proteins composed of peptide cytotoxins covalently linked to target cell-selective peptide ligands such as monoclonal antibodies, antibody fragments, growth factors, or cytokines. Immunotoxins have been synthesized that kill cells selectively in tissue culture with great potency and have excellent in vivo efficacy with short treatment courses in immunocompromised rodents bearing human tumor xenografts. However, clinical benefit from these genetically engineered molecules has been compromised by the strong humoral immune response to these foreign proteins. Humoral immunity reduces the serum half-life and inhibits cytotoxicity (1 , 2) . A number of approaches have been tested to reduce the immune response (Fig. 1)Citation .



View larger version (13K):
[in this window]
[in a new window]
  		Fig. 1. Schema of interventions that may reduce immunotoxin immunogenicity. A, patient selection of the following diseases with pre-existent immunosuppression or sanctuary sites: chronic lymphocytic leukemia (CLL); post-bone marrow transplantation (Post-BMT); and interstitial therapy of gliomas. B, immunosuppressive compounds as follows: deoxyspergualin (DSG), CTLA4Ig, cyclosporine (CYA), cyclophosphamide (CTX), anti-CD4 antibody, and anti-CD20 antibody. C, modified immunotoxins as follows: polyethylene glycol (PEG) conjugates, human toxins and ligands, and immunodominant epitope modified.

 
Administration of immunosuppressive agents with immunotoxins has been tested in animals and patients. Cyclophosphamide and cyclosporine did not prevent anti-immunotoxin synthesis in patients treated with a mouse monoclonal antibody-ricin A chain conjugate (3 , 4) . CTLA4Ig was able to block anti-immunotoxin production in rodents and dogs (5) , and deoxyspergualin was able to reduce anti-immunotoxin synthesis in rodents and dogs (6) but not substantially in primates (7) . Anti-CD4 monoclonal antibodies blocked anti-immunotoxin generation in mice (8) . No clinical trials of combined CTLA4Ig, deoxyspergualin, or anti-CD4 antibody and immunotoxin have been reported. Rituximab has been tested in two clinical studies in combination with recombinant Pseudomonas exotoxin immunotoxins (9 , 10) . In a study by Hassan et al. (9) reported in this issue of Clinical Cancer Research, administration of rituximab beginning 3 days before immunotoxin did not prevent anti-immunotoxin antibody formation. In contrast, Saleh et al. (10) found good inhibition of anti-immunotoxin antibody synthesis with rituximab pretreatment for two weeks (four doses) before initiating immunotoxin therapy. It is unclear whether the differences in these two studies are secondary to timing of rituximab or other differences in patient characteristics or immunotoxin properties.

Altering the structure of the immunotoxin is another approach to reduce immunogenicity. Polyethylene glycol modified immunotoxin showed reduced immunogenicity and improved serum half-life and antitumor activity in mice (11 , 12) . Site-specific mutagenesis of one toxin, Pseudomonas exotoxin, has been performed to generate variant toxins with removal of monkey sera-defined immunodominant epitopes (13) . No clinical testing has been performed with either polyethylene glycol-modified or immunodominant epitope-modified immunotoxins. "Humanized" immunotoxins have been synthesized by using a human or mammalian toxin (e.g., RNase, protamine/DNA, and Bax) and a human ligand (e.g., monoclonal antibody, cytokine, or growth factor). As shown in Table 1Citation , toxicity to tumor cells was observed, but in most cases, the potency was 1000- to 1 million-fold less than "traditional" immunotoxins. No human studies have been reported with these agents.


View this table:
[in this window]
[in a new window]
  		Table 1 "Humanized" Immunotoxinsa

 
A third avenue is to use immunotoxins in a disease setting where there is an impaired immune response. Immunotoxin therapy of chronic lymphocytic leukemia has been associated with lower anti-immunotoxin serum titers (22) . Similarly, interstitial brain tumor therapy has yielded lower systemic antibody titers and lack of effect of these antibodies on brain tumor pharmacodynamics (23) .

Where do we go from here? First, a quantitative, reproducible assay for humoral immune response will permit more accurate comparison of immune interventions. The assays of Hall et al. and Hertler et al. provide internal standards and immunoglobulin quantitation (1 , 2) . Second, patient selection is important. Patients should be stratified for prior exposure to the toxin or ligand moiety. Patients with pretreatment immunity are more likely to mount an amnestic immune response. Third, agents with sufficient clinical activity during the first cycle or month should be selected for tolerance induction. If the agent has little clinical activity in the preantibody period, it will be unlikely to show improved antitumor efficacy with immune modulation. Fourth, clinical testing is warranted with CTLA4Ig, deoxyspergualin, anti-CD4 and different schedules of rituximab. Several weeks of rituximab may be required to condition patients to tolerate foreign antigens. Fifth, the clinical development of "humanized immunotoxins" may accelerate the field similar to the effects of monoclonal antibody "humanization" on the introduction of monoclonal antibody serotherapy into clinical practice. Although clinical investigators and physicians have waited several decades for the promises of immunotoxin therapy, we can see steady progress in the field and renewed hopes for expanding the role of immunotoxins in the clinical oncology armamentarium.

FOOTNOTES

The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby marked advertisement in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.

Requests for reprints: Arthur E. Frankel, Department of Medicine, Wake Forest University School of Medicine, Medical Center Boulevard, Winston-Salem, North Carolina 27157. Phone: (336) 716-3316; Fax: (336) 716-9113; E-mail: afrankel{at}wfubmc.edu

Received 11/ 4/03; revised 11/18/03; accepted 11/18/03.

REFERENCES

  1. Hall P. D., Virella G., Willoughby T., Atchley D. H., Kreitman R. J., Frankel A. E. Antibody response to DT-GM, a novel fusion toxin consisting of truncated diphtheria toxin (DT) linked to human granulocyte-macrophage colony-stimulating factor (GM), during a phase I trial of patients with relapsed or refractory acute myeloid leukemia. Clin. Immunol., 100: 191-197, 2001.[CrossRef][Medline]
  2. Hertler A. A., Spitler L. E., Frankel A. E. Humoral immune response to a ricin A chain immunotoxin in patients with metastatic melanoma. Cancer Drug Delivery, 4: 245-253, 1987.[Medline]
  3. Oratz R., Speyer J. L., Wernz J. C., Hochster H., Meyers M., Mischak R., Spitler L. E. Antimelanoma monoclonal antibody-ricin A chain immunoconjugate (XMMME-001-RTA) plus cyclophosphamide in the treatment of metastatic malignant melanoma: results of a phase II trial. J. Biol. Response Modif., 9: 345-354, 1990.[Medline]
  4. Selvaggi K., SAria E. A., Schwartz R., Vlock D. R., Ackerman S., Wedel N., Kirkwood J. M., Jones H., Ernstoff M. S. Phase I/II study of murine monoclonal antibody-ricin A chain (XOMAZYME-Mel) immunoconjugate plus cyclosporine A in patients with metastatic melanoma. J. Immunother., 13: 201-207, 1993.[Medline]
  5. Siegall C. B., Haggerty W. G., Warner G. L., Chace D., Mixan B., Longley P. S., Davidson T. Prevention of immunotoxin-induced immunogenicity by coadministration with CTLA4Ig enhances antitumor efficacy. J. Immunol., 159: 5168-5173, 1997.[Abstract]
  6. Pai L. H., FitzGerald D. J., Tepper M., Schacter B., Spitalny G., Pastan I. Inhibition of antibody response to Pseudomonas exotoxin and an immunotoxin containing Pseudomonas exotoxin by 15-deoxyspergualin in mice. Cancer Res., 50: 7750-7753, 1990.[Abstract/Free Full Text]
  7. Hubbard W. J., Moore J. K., Contreras J. L., Smyth C. A., Chen Z. W., Lobashevsky A. L., Nagata K., Neville D. M., Thomas J. M. Phenotypic and functional analysis of T-cell recovery after anti-CD3 immunotoxin treatment for tolerance induction in rhesus monkeys. Hum. Immunol., 62: 479-487, 2001.[CrossRef][Medline]
  8. Jin F-S., Youle R. J., Johnson V. G., Shiloach J., Fass R., Longo D. L., Bridges S. H. Suppression of the immune response to immunotoxins with anti-CD4 monoclonal antibodies. J. Immunol., 146: 1806-1811, 1991.[Abstract]
  9. Hassan R., Williams-Gould J., Watson T., Pai-Scherf L., Pastan I. Pretreatment with rituximab does not inhibit the human immune response against the immunogenic protein, LMB-1. Clin. Cancer Res., 10: 16-18, 2004.[Abstract/Free Full Text]
  10. Saleh M. N., Bookman M., Mauer A., Posey J., Rinehart J., Fleming G., Meropol N., Khazaeli M., Thornton J., Sprague E., Schol J., Yeslow G., Lorenz J., Siegall C., Sing A., LoBuglio A. Rituximab delays human anti-toxoin antibody onset: phase I study of SGN-10 (BR96 sFv-PE40) in patients with advanced stage carcinoma. Proc. Am. Soc. Clin. Oncol., 21: 28a 2002.
  11. Wang Q. C., Pai L. H., Debinski W., FitzGerald D. J., Pastan I. Polyethylene glycol-modified chimeric toxin composed of transforming growth factor alpha and Pseudomonas exotoxin. Cancer Res., 53: 4588-4594, 1993.[Abstract/Free Full Text]
  12. Tsutsumi Y., Onda M., Nagata S., Lee B., Kreitman R. J., Pastan I. Site-specific chemical modification with polyethylene glycol of recombinant immunotoxin anti-Tac(Fv)-PE38 (LMB-2) improves antitumor activity and reduces animal toxicity and immunogenicity. Proc. Natl. Acad. Sci. USA, 97: 8548-8553, 2000.[Abstract/Free Full Text]
  13. Roscoe D. M., Jung S. H., Benhar I., Pai L., Lee B. K., Pastan I. Primate antibody response to immunotoxin: serological and computer-aided analysis of epitopes in a truncated form of Pseudomonas exotoxin. Infect. Immun., 62: 5055-5065, 1994.[Abstract/Free Full Text]
  14. Rybak S. M., Hoogenboom H. R., Newton D. L., Raus J. C., Youle R. J. Rational immunotherapy with ribonuclease chimeras. An approach toward humanizing immunotoxins. Cell Biophys., 21: 121-138, 1992.[Medline]
  15. Rybak S. M., Hoogenboom H. R., Meade H. M., Raus J. C., Schwartz D., Youle R. J. Humanization of immunotoxins. Proc. Natl. Acad. Sci. USA, 89: 3165-3169, 1992.[Abstract/Free Full Text]
  16. Psarras K., Ueda M., Yamamura T., Ozawa S., Kitajima M., Aiso S., Komato S., Seno M. Human pancreatic RNaseI-human epidermal growth factor fusion is an entirely human immunotoxin analog with cytotoxic properties against squamouse cell carcinomas. Protein Eng., 11: 1285-1292, 1998.[Abstract/Free Full Text]
  17. Psarras K., Ueda M., Tanabe M., Kitajima M., Aiso S., Komatsu S., Seno M. Targeting activated lymphocytes with an entirely human immunotoxin analogue: human pancreatic RNase1-human IL-2 fusion. Cytokine, 12: 786-790, 2000.[CrossRef][Medline]
  18. Huhn M., Sasse S., Tur M. K., Matthey B., Schinkothe T., Rybak S. M., Barth S., Engert A. Human angiongenin fused to human CD30ligand (Ang-CD30L) exhibits specific cytotoxicity against CD30-positive lymphoma. Cancer Res., 61: 8737-8742, 2001.[Abstract/Free Full Text]
  19. Chen S. Y., Zani C., Khouri Y., Marasco W. A. Design of a genetic immunotoxin to eliminate toxin immunogenicity. Gene Ther., 2: 116-123, 1995.[Medline]
  20. Newton D. L., Hansen H. J., Liu H., Ruby D., Iordanov M. S., Magun B. E., Goldenberg D. M., Rybak S. M. Specifically targeting the CD22 receptor of human B-cell lymphomas with RNA damaging agents. Crit. Rev. Oncol. Hematol., 39: 79-86, 2001.[Medline]
  21. Angilan R., Yarkoni S., Lorberboum-Galski H. Interleukin 2-Bax: a novel prototype of human chimeric proteins for targeted therapy. FEBS Lett., 457: 271-276, 1999.[CrossRef][Medline]
  22. Hertler A. A., Schlossman D. M., Borowitz M. J., Blythman H. E., Casellas P., Frankel A. E. An anti-CD5 immunotoxin for chronic lymphocytic leukemia: enhancement of cytotoxicity with human serum albumin-monensin. Int. J. Cancer, 43: 215-219, 1989.[Medline]
  23. Laske D. W., Youle R. J., Oldfield E. H. Tumor regression with regional distribution of the targeted toxin Tf-CRM107 in patients with malignant brain tumors. Nat. Med., 3: 1362-1368, 1997.[CrossRef][Medline]



This article has been cited by other articles:


Home page
 Molecular Cancer TherapeuticsHome page
T. R. Daniels, P. P. Ng, T. Delgado, M. R. Lynch, G. Schiller, G. Helguera, and M. L. Penichet
Conjugation of an anti transferrin receptor IgG3-avidin fusion protein with biotinylated saporin results in significant enhancement of its cytotoxicity against malignant hematopoietic cells
Mol. Cancer Ther., November 1, 2007; 6(11): 2995 - 3008.
[Abstract] [Full Text] [PDF]

Home page
 Cancer Res.Home page
Y. Su, J. Ortiz, S. Liu, T. H. Bugge, R. Singh, S. H. Leppla, and A. E. Frankel
Systematic Urokinase-Activated Anthrax Toxin Therapy Produces Regressions of Subcutaneous Human Non-Small Cell Lung Tumor in Athymic Nude Mice
Cancer Res., April 1, 2007; 67(7): 3329 - 3336.
[Abstract] [Full Text] [PDF]

Home page
 Clin. Cancer Res.Home page
T. F. Liu, P. D. Hall, K. A. Cohen, M. C. Willingham, J. Cai, A. Thorburn, and A. E. Frankel
Interstitial Diphtheria Toxin-Epidermal Growth Factor Fusion Protein Therapy Produces Regressions of Subcutaneous Human Glioblastoma Multiforme Tumors in Athymic Nude Mice
Clin. Cancer Res., January 1, 2005; 11(1): 329 - 334.
[Abstract] [Full Text] [PDF]

This Article
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Frankel, A. E.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Frankel, A. E.

HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
Cancer Research Clinical Cancer Research
Cancer Epidemiology Biomarkers & Prevention Molecular Cancer Therapeutics
Molecular Cancer Research Cancer Prevention Research
Cancer Prevention Journals Portal Cancer Reviews Online
Annual Meeting Education Book Cell Growth & Differentiation