Interferons in the treatment of human neoplasms

Interferon-induced hypothyroidism causing reversible pituitary enlargement

OBJECTIVE

To present the first reported case of interferon-induced hypothyroidism with radiographic confirmation of secondary pituitary hyperplasia.

METHODS

We describe the case of a woman with recurrent malignant melanoma, outline the details of her endocrine work-up, and illustrate the serial findings on magnetic resonance imaging of the head.

RESULTS

A 26-year-old woman underwent surgical excision of a melanoma of the left thigh and 10 years later had a second melanoma removed from her right knee. Metastatic work-up revealed evidence of tumor involvement in the cervical and mediastinal lymph nodes. After treatment with interferon for 1 year, persistent fatigue and menstrual irregularities led to the laboratory diagnosis of hypothyroidism, and magnetic resonance imaging revealed pituitary enlargement. Both her endocrinopathy and the pituitary hyperplasia resolved with discontinuation of the interferon treatment and with institution of thyroid replacement therapy.

CONCLUSION

Clinicians should be aware of the potential adverse effects of interferon therapy to avoid inappropriate diagnosis of a pituitary adenoma or metastatic lesion in patients with cancer who are treated with interferon. In addition, screening for hypothyroidism should be performed in patients receiving interferon.

In vivo expression of an interferon-alpha gene by intramuscular injection of naked DNA

Acid-stable type I interferons belong to a multigene family. The biologic relevance of each subtype in vivo remains unknown. We have developed an experimental model in which muscles were transfected in situ with naked DNA plasmids encoding an IFN transgene to assess the roles of individual IFN subtypes in vivo. Murine IFN-alpha 9 gene was subcloned into several mammalian expression vectors. Adult C57BL/6 mice were injected bilaterally in regenerating tibialis anterior muscles with naked DNA 5 days after muscle injury to enhance DNA uptake and expression. In the muscles of mice given the IFN-alpha 9 plasmid constructs, acid-stable IFNs were detected by bioassay using reduction in cytopathic effect of encephalomyocarditis virus-infected L929 cells. In these same muscles, IFN-alpha 9 transcripts were identified by RT-PCR, indicating that transcription had occurred. Acid-stable IFNs were detected from days 7 to 28 post-DNA inoculation. Furthermore, these proteins were found in the sera of DNA-inoculated mice. Control groups of mice given the blank expression vectors did not produce detectable IFNs in muscle or sera as determined by bioassay, nor were transcripts detected by RT-PCR. This approach now allows investigation of the effector function of individual subtypes in various murine disease models.

Antibodies to interferon-alpha in treated cancer patients: incidence and significance

Antibodies to interferon-alpha (IFN-alpha) are found in some patients being treated with this cytokine. In studies in which two recombinant IFN-alpha preparations were directly compared in cancer patients, those given IFN-alpha2a were found to have neutralizing antibodies in their serum significantly more often than those given IFN-alpha2b (p <0.001). Patients who develop neutralizing antibodies are more likely to have a clinical relapse and to become resistant to further treatment with at least the IFN preparation initially used for their treatment. In 10 studies in cancer patients, such an outcome was found in 63% of those who developed antibodies but in only 13% of those who did not. These data are tabulated.

The type-I interferon receptor. The long and short of it

The type-I interferon receptor is a multisubunit receptor of the cytokine receptor superfamily. The production of specific monoclonal antibodies against the receptor and the cloning of different receptor subunits have contributed to understanding the type-I interferon receptor structure and function. The present article analyzes these new advances and the role of the different receptor subunits in type-I interferon signaling.

Phase I-II trial of recombinant interferon alpha-2b with cisplatin and 5-fluorouracil in recurrent and/or metastatic carcinoma of head and neck

The aims of this study were to establish the feasibility and toxicity of the biochemical modulation of the cisplatin (CDDP)-5FU combination by interferon alpha-2b (INF), and to assess its therapeutic efficacy in recurrent and/or metastatic squamous cell carcinoma of the head and neck (SCCHN). The mandatory eligibility criteria included histologically proven SCCHN; a performance status <2; adequate bone marrow, hepatic, renal, and cardiac functions; and measurable and/or evaluable disease. The protocol was CDDP, 100 mg/m2 i.v. day 1; 5-FU, 1,000 mg/m2 in a c.i.v. infusion over 96 h; and INF 3.10(6) U/day s.c., begun 2 h before cisplatinum for 5 consecutive days, repeated every 3 weeks. Twenty patients were included and received 76 cycles (median number cycles/patient = three). Eighteen patients were evaluable for activity with an overall response rate (RR) of 30% [2 complete responses (CR) + 4 partial responses (PR)], which was 55% (5/9) in previously untreated and 9% (1/11) in previously treated patients. Myelosuppression (50%), mucositis (40%), loss of electrolytes (15%), and asthenia (20%) were the most frequent severe toxic effects. Notwithstanding, the protocol was feasible and well tolerated in this overall population with a poor prognosis. Median duration of response was 8 months, and median survival for the overall population was 8.5 months. This schedule is the test arm of an ongoing international multicentric phase III trial versus standard CDDP-5FU in the same SCCHN population.

Interferon-alpha inhibits erythropoietin-induced proliferation, but not differentiation, and restricts erythroleukemia development

The immature erythroid cell line J2E responds to erythropoietin (Epo) by proliferating and terminally differentiating into hemoglobin-synthesizing red blood cells. These cells produce a rapid, fatal erythroleukemia in mice characterized by hepatosplenomegaly and severe anemia. The aim of this study was to investigate the effects of murine interferons-alpha (MuIFN-alpha) on J2E cells in vitro and in vivo. Here we show that in culture MuIFN-alpha inhibited the Epo-induced proliferation of J2E cells but did not interfere with differentiation. When mice with J2E erythroleukemias were treated with MuIFNs in vivo, an extension of their life span was observed. Moreover, numerous necrotic lesions of infiltrating leukemic cells were detected in the spleens of these mice. Finally, ex vivo treatment of leukemic bone marrow cells with Epo and MuIFNs delayed mortality even further. It was concluded that MuIFNs (1) suppressed the proliferation of J2E cells in vitro but did not affect Epo-induced differentiation, and (2) inhibited the progress of erythroleukemias, especially in combination with Epo.

Preliminary trial of nonrecombinant interferon alpha in recurrent squamous cell carcinoma of the head and neck

Fourteen patients with recurrent squamous cell carcinoma of the head and neck (SCCHN) were treated with 10 x 10(6) U of nonrecombinant interferon alpha (IFN) intramuscularly (IM) daily for 3 days every 28 days. There were 11 men and 3 women, with ages ranging from 48 to 74 years. Patients had previously been treated with surgery (9 patients), radiotherapy (13 patients), or chemotherapy (8 patients). All patients had measurable disease by physical exam and radiologic evaluation and a performance status of less than or equal to 2 (ECOG). Patients were treated for a minimum of 3 months and continued on therapy until disease progression. The dose and treatment schedule of IFN was well-tolerated. Toxicities included low-grade fever, mild anorexia, and malaise. Treatment was stopped in 1 patient due to the development of atrial fibrillation. One death occurred as a complication of aspiration pneumonia 2 weeks following the onset of therapy and was not felt to be related to IFN therapy. Of the 14 patients treated, there was 1 complete response (30+ months) of a base of tongue primary. Two patients had stabilization of disease (SD, 8 and 12 months). One patient had a mixed response with resolution of subcutaneous nodules. The remaining 10 patients died of progressive disease. Immunological assessment was performed on 8 patients. The 1 patient who had a complete response was noted to have markedly low pretreatment natural killer (NK) cell activity and a subsequent sharp rise in activity after initial treatment. We conclude that low-dose cyclic IFN is well-tolerated in patients with recurrent SCCHN and has potential antitumor activity.

Disseminated malignant melanoma and recombinant interferon: analysis of seven consecutive phase II investigations

We have performed seven phase II trials with recombinant interferons (IFN) involving 191 patients with biopsy-proved, measurable disseminated malignant melanoma. The regimens and numbers of patients have included IFN-alpha 2A, 50 X 10(6) U/m2 subcutaneous (SQ) TIW (regimen A, 31 patients); IFN-alpha 2A, 12 X 10(6) U/m2 SQ TIW (regimen B, 30 patients); IFN-alpha 2A with cimetidine as an immunorestorative agent (regimen C, 35 patients); IFN-gamma (regimen E, 29 patients); IFN-alpha 2A with IFN gamma (Regimen E, 20 patients); IFN-alpha 2A with bis-chloroethylnitrosourea (BCNU) (regimen F, 30 patients); and IFN-alpha 2A with the biochemical modulator, difluoromethylornithine (DFMO) (regimen G, 16 patients). The objective regression rates were as follows: A, 23%; B, 20%; C, 23%; D, 10%; E, 5%; F, 7%; G, 0%. Despite the higher response rate from regimen A, there appeared to be no survival advantage from any of these programs. The median time to progression was 1 month with a median survival time of 6 months. Most regressions involved soft tissue disease, were partial, and occurred within 2-3 months of treatment. Four patients received IFN for approximately 6 months and have manifested extraordinarily durable regressions of greater than 4+ years. The alpha-regimens produced a flu-type illness and anorexia which were dose-related. Leukopenia was most noteworthy with regimens containing gamma-interferon. Ongoing trials involving alternative and improved immune-related modalities are awaited with keen interest.

Characterization of three monoclonal antibodies that recognize the interferon alpha 2 receptor

The interferon system plays an important role in the control of viral infections and cell proliferation. These effects are mediated through the interaction of interferons with specific cell surface receptors. We report here the development of monoclonal antibodies against one of the subunits of the interferon alpha receptor. These antibodies detect a 110-kDa protein in surface-labeled cells and in Western blots, and 130- and 210-kDa bands after crosslinking to iodinated interferon alpha 2. No other subunits are disulfide-linked to the 130-kDa subunit or are coprecipitated by these antibodies. Analysis by two-dimensional gel electrophoresis revealed that the pI of this subunit is 3.5-5.0. We suggest that the protein recognized by these monoclonal antibodies be named the alpha subunit of the interferon alpha receptor.

Low incidence of anti-interferon-alpha antibodies in patients treated with interferon-alpha-2a for AIDS-associated Kaposi's sarcoma

Anti-interferon (IFN)-alpha antibodies were determined in the serum of 28 patients treated with high-dose human recombinant IFN-alpha-2a for AIDS-associated Kaposi's sarcoma. After a median treatment duration of 3 months, 3 patients developed anti-IFN-alpha antibodies, of whom 2 showed a long lasting tumour response despite the development of these antibodies. None of 3 patients with tumour progression after an initial treatment response had developed IFN-alpha neutralizing antibodies. In conclusion, a low incidence of anti-IFN-alpha antibodies during treatment with high dose IFN-alpha was found, but the appearance had no detrimental effect on the duration of tumour responses in a small number of patients.

Indomethacin augments lymphokine-activated killer cell generation by patients with malignant mesothelioma

Human malignant mesothelioma (MM) cells are resistant to natural killer (NK) cell lysis but susceptible to lysis by lymphokine-activated killer (LAK) cells from control individuals. The present study was performed to determine the capacity of patients with MM (n = 22) and individuals occupationally exposed to asbestos (the major population at risk of developing this disease, n = 52) to generate LAK cells capable of effectively lysing human mesothelioma cells. Compared to controls (n = 20), both patient groups demonstrated significantly depressed LAK cell activity against mesothelioma tumor cell targets (55 +/- 3% lysis by controls vs 34 +/- 3% lysis by patients with MM, P less than 0.005; and 45 +/- 3% lysis by asbestos-exposed individuals, P less than 0.025). Addition of 10 micrograms/ml indomethacin during LAK cell generation restored normal LAK cell activity for patients with MM (52 +/- 6% lysis of cultured human MM cells, P = NS compared to controls), suggesting that the defective cytolytic cell function observed in some patients with MM is a result of prostaglandin-induced immunosuppression. The ability of indomethacin to restore suppressed LAK cell activity in patients with MM suggests that the concomitant use of this agent in ex vivo LAK cell generation and in patients undergoing interleukin/LAK cell therapy may be beneficial.

Interferons: biological and clinical effects

Interferons play a key role in the immune system as biological response modifiers. Interferons alpha, beta, and gamma have been characterized, their nucleotide sequences defined, and the proteins produced by recombinant DNA technology. The myriad actions of interferons include enhancement of natural killer cell activity and antigen expression, induction of varied proteins, activation of macrophages, and antiviral, antiproliferative and antitumor effects. Clinical trials have demonstrated efficacy of interferons in some malignancies and ongoing studies are investigating results of combinations with other biological response modifiers and cytotoxic agents.