Recombinant interferon α-2A combined with prednisone in metastatic renal-cell carcinoma: Treatment results, serum interferon levels and the development of antibodies

Glycosylation shapes the efficacy and safety of diverse protein, gene and cell therapies

Over recent decades, therapeutic proteins have had widespread success in treating a myriad of diseases. Glycosylation, a near universal feature of this class of drugs, is a critical quality attribute that significantly influences the physical properties, safety profile and biological activity of therapeutic proteins. Optimizing protein glycosylation, therefore, offers an important avenue to developing more efficacious therapies. In this review, we discuss specific examples of how variations in glycan structure and glycoengineering impacts the stability, safety, and clinical efficacy of protein-based drugs that are already in the market as well as those that are still in preclinical development. We also highlight the impact of glycosylation on next generation biologics such as T cell-based cancer therapy and gene therapy.

Interferon alpha for the treatment of advanced renal cancer

This paper is an overview on the place of IFN-alpha in metastatic renal cell carcinoma (MRCC). After a presentation of MRCC and the mode of action of IFN-alpha, the results of studies including IFN-alpha alone or in combination with IL-2, chemotherapy and other biological modifiers are presented. Finally, new trends for new drugs, including antiangiogenic therapies, are discussed.

Dexamethasone and interleukin-2 combination therapy for advanced renal cell carcinoma in a patient with paraneoplastic inflammatory syndrome

Interleukin-2 (IL-2) in combination with dexamethasone was administered to a 48-year-old man with renal cell carcinoma accompanied by paraneoplastic inflammatory syndrome, including progressive multiple lung metastases and inferior vena caval tumor thrombus. Although non-steroidal anti-inflammatory drugs had no apparent antipyretic effect on the systemic inflammatory syndrome, oral administration of dexamethasone achieved complete antipyresis and improved his quality of life. After a 4-week period of IL-2 treatment, regression of metastasized lesions was demonstrated despite concurrent oral administration of dexamethasone. Steroids might reduce the action of immunotherapeutic drugs, but in some cases, combination therapy can achieve both alleviation of the paraneoplastic syndrome and tumor shrinkage.

Immunogenicity of therapeutic proteins: clinical implications and future prospects

BACKGROUND

Therapeutic proteins have revolutionized the treatment of many diseases. In the near future, many more therapeutic proteins are likely to become available for an increasingly wide range of indications.

OBJECTIVES

This article reviews the incidence, causes, and consequences of formation of antibodies to therapeutic proteins and suggests ways to address issues surrounding immunogenicity.

METHODS

Searches of MEDLINE and EMBASE databases were performed, covering the period 1990 to May 2002. Search terms included immunogenicity, antibodies, and the names of specific therapeutic proteins and classes of therapeutic proteins. Bibliographies of retrieved articles were not searched.

RESULTS

All exogenous proteins, including therapeutic ones, have the potential to cause antibody formation. The reported incidence of antibody formation with therapeutic proteins varies widely between proteins and between studies (depending on the assay techniques used). The clinical consequences of antibody formation vary with the type of antibody present; for example, neutralizing antibodies are more likely to cause loss of efficacy than nonneutralizing antibodies. The immunogenicity of therapeutic proteins can be influenced by many factors, including the genetic background of the patient, the type of disease, the type of protein (human or nonhuman), the presence of conjugates or fragments, the route of administration, dose frequency, and duration of treatment. Manufacturing, handling, and storage can introduce contaminants, or alter the 3-dimensional structure of the protein via oxidation or aggregate formation. Various means have been suggested by which therapeutic proteins might be modified to reduce their immunogenicity, including PEGylation, site-specific mutagenesis, exon shuffling, and humanization of monoclonal antibodies. In the future, it may even be possible to predict the immunogenicity of new therapeutic proteins more accurately, using specifically designed animal models, including nonhuman primates and transgenic mice.

CONCLUSIONS

Scientists and clinicians are becoming increasingly aware of the importance of assessing the immunogenicity of new molecules as they are introduced, and of existing molecules whenever they are modified or their manufacturing process is changed. Immune responses to therapeutic proteins are usually only of clinical significance if they are associated with the development of treatment resistance. Although various means to reduce the immunogenicity of therapeutic proteins have been suggested, monitoring for antibodies during clinical trials and postmarketing surveillance remains an important issue for all therapeutic proteins.

Human immune response to recombinant human proteins

Delivery of pharmacological doses of proteins to people has raised concerns of inducing immune responses, especially when the protein is provided in multiple doses over an extended period of time. Immune responses could impact the therapeutic exposure and efficacy of the protein itself. In addition, there have been fears of anaphylaxis or autoimmunity. This review summarizes the available literature regarding the measurement and evaluation of immune responses observed during clinical assessment of recombinant human proteins. Immune responses have ranged from none at all to inactivation and/or accelerated clearance. Presence of antibodies does not necessarily impact therapeutic viability. While responses are related to frequency and route of delivery, there is no clear relationship that enables one to predict the clinical experience.

Interferons Alpha, Beta, and Omega

Interferon alpha (IFN-α) is a mixture of closely related proteins, termed “subtypes,” expressed from distinct chromosomal genes. Interferon β (IFN-β) is a single protein species and is molecularly related to IFN-α subtypes, although it is antigenically distinct from them. IFN omega (IFN-ω) is antigenically distinct from IFN-α and IFN-β but is molecularly related to both. The genes of three IFN subtypes are tandemly arranged on the short arm of chromosome 9. They are transiently expressed following induction by various exogenous stimuli, including viruses. They are synthesized from their respective mRNAs for relatively short periods following gene activation and are secreted to act, via specific cell surface receptors, on other cells. IFN-α subtypes are secreted proteins and as such are transcribed from mRNAs as precursor proteins, pre-IFN-α, containing N-terminal signal polypeptides of 23 hydrophobic amino acids (aa) mainly. Pre-IFN-β contains 187 aa, of which 21 comprise the N-terminal signal polypeptide and 166 comprise the mature IFN-β protein. IFN-ω contains 195 aa—the N-terminal 23 comprising the signal sequence and the remaining 172, the mature IFN-ω protein. At the C-terminus, the aa sequence of IFN-ω is six residues longer than that of IFN-α or IFN-β proteins. IFN-α, as a mixture of subtypes, and IFN-ω may be produced together following viral infection of null lymphocytes or monocytes/macrophages. The biological activities of IFNs are mostly dependent upon protein synthesis with selective subsets of proteins mediating individual activities. IFNs can also stimulate indirect antiviral and antitumor mechanisms, depending upon cellular differentiation and the induction of cytotoxic activity.

Common cancers--immunotherapy and multidisciplinary therapy: Parts III and IV

The refractoriness of many solid tumors to cytotoxic chemotherapy has led to the exploration of new therapeutic modalities, including immunotherapy. Immunotherapy does not have a direct cytotoxic effect on the cancer cell but is an attempt to promote rejection of the tumor by the host, chiefly through the cellular arm of the immune system. The clinical success with immunotherapy (primarily adoptive immunotherapy) among patients with unresectable malignant melanoma and cancer of the kidney has not been marked by the large numbers of patients responding but by occasional dramatic effectiveness of therapy for these cancers, which usually are refractory to chemotherapy. Long-lasting responses and even complete disappearance of all known metastases are possible for a small percentage of patients with melanoma or renal cell carcinoma who undergo immunotherapy. A reasonable approach for patients with good performance status (no symptoms or ambulatory with symptoms but not bedridden) is entrance to clinical trials, especially trials examining adoptive or active immunotherapy for melanoma or adoptive immunotherapy for renal cancer. The overall treatment of patients with cancer has changed. Primary-care physicians detect almost all cancers. The days when "taking it out" is the best we could offer a patient are over. As we learn more about the use of adjuvant or neoadjuvant chemotherapy and radiation therapy, it is likely one or both of these modalities will be incorporated into the treatment of additional solid tumors previously managed solely with surgical resection. Increasingly, additional therapy is being given for earlier-stage disease as we define how to maximize the potential for cure with minimal toxicity. Many new therapies are on the horizon, including the use of noncytotoxic treatments as an adjunct to a surgical procedure. Such therapies include the use of angiogenesis inhibitors, tumor vaccines, and immunotherapy. Now and in the future, patients will be best served when treated in an environment that can integrate medical, surgical, and radiation oncology actively.

Interferon-alpha, 5-FU and prednisone in metastatic renal cell carcinoma: a phase II study

BACKGROUND

Due to the possibility of a synergistic effect between Interferon (IFN-alpha) and 5-fluorouracil (5-FU), a phase II trial was conducted in metastatic renal cell carcinoma (MRCC) combining recombinant IFN-alpha, 5-FU and prednisone. Prednisone has been shown to decrease IFN-alpha-related toxicity without reducing the response rate.

PATIENTS AND METHODS

Thirty-one patients with measurable MRCC were entered into the trial; 16 of them had lung metastases only. In 26 patients (nos. 6-31) the following dose schedule was applied during an 8-week treatment cycle: IFN-alpha (Roferon, Roche, Basel, Switzerland): 12 x 10(6)U s.c. 3 times weekly; Days 1-5: 5-FU: 600 mg/m2/day continuous i.v. infusion; Weeks 3-8: 5-FU 600 mg/m2 x 1 weekly (bolus i.v.); prednisone: 10 mg x 2 per os daily for 2 weeks, and thereafter 5 mg x 2. In the first 5 patients higher doses of 5-FU led to unacceptable toxicity and subsequent dose alteration of the trial schedule. All 31 patients were evaluable for response. Seventy treatment cycles were given.

RESULTS

One complete and 6 partial responses were observed (response rate: 23%, 95% CI: 10%-41%), with a median response duration of 11 months. Except in one patient, hematological toxicity was confined to grades I and II. Eight patients developed grade III oral mucositis. Adverse cardiac events were observed in 3 patients. Dose modifications of 5-FU were necessary in 16 cycles. The IFN-alpha doses were transiently reduced during 8 cycles.

CONCLUSION

The assessed combination of IFN-alpha, 5-FU and prednisone is moderately active in MRCC, with response rates similar to those seen in patients on IFN-alpha monotherapy. The latter treatment approach seems preferable, as 5-FU-related toxicity (mucositis, cardiac toxicity) is averted.