Annette E. Maluish

The determination of an immunologically active dose of interferon-gamma in patients with melanoma.

This study was undertaken to determine an immunologically active regimen for the administration of recombinant gamma-interferon (rIFN-gamma). The patient population included patients with completely resected melanoma, stage I (Clarks level IV or V) or stage II. All patients exhibited no evidence of disease (NED) at the time of the study. Patients received rIFN-gamma by intramuscular (IM) injection daily for 15 days at 0.0001 mg/m2, 0.001 mg/m2, 0.01 mg/m2, 0.1 mg/m2 (ten patients/group), or 0.25 mg/m2 (five patients). Interferon (IFN) was well tolerated, with non-dose-limiting constitutional symptoms occurring in the majority of patients at 0.1 mg/m2 and 0.25 mg/m2. All five patients receiving 0.25 mg/m2 developed elevated transaminase levels, which led to a discontinuation of therapy in one patient. Immunological activity was assessed by serial measurements of natural killer (NK) cell activity, hydrogen peroxide production by monocytes, and changes in expression of Fc receptors and human leukocyte class II antigen (HLA-DR) on monocytes. These changes were determined at baseline (X2), six to seven time points during rIFN-gamma therapy, and two times after the last dose of rIFN-gamma. No changes were observed at the two lowest doses. At the 0.01 mg/m2 dose, all parameters were elevated but not as consistently nor to the same levels as seen following administration of 0.1 mg/m2. At 0.25 mg/m2, H2O2 production was enhanced, but unlike at 0.1 mg/m2, it declined during the last few days of IFN therapy. Subcutaneous (SC) administration was compared with IM administration using the 0.1 mg/m2 dose. SC administration resulted in enhanced H2O2 production and Fc receptor expression by monocytes. More consistent elevations in peroxide generation and higher levels of Fc receptor expression were seen following SC administration. No significant difference was found between the two routes of administration. A comparison of two schedules, daily and three times weekly, suggested that monocyte activation may return to normal 72 hours after IFN administration. Of the doses tested, 0.1 mg/m2 administered daily appeared to be the most effective biological response modifier (BRM) regimen, and because of ease of administration, we favor the SC route.

A system for obtaining large numbers of cryopreserved human monocytes purified by leukapheresis and counter-current centrifugation elutriation (CCE).

A system has been developed for the isolation of large numbers of unfractionated mononuclear cells from single, well characterized normal individuals and for the separation by elutriation of these cells into populations of greater than 90% pure monocytes and greater than 99% pure lymphocytes. The total number of monocytes obtained from a single donor averaged about 550 million. After cryopreservation and thawing of these cells, the viability remained greater than 90%, 80% of original cells were recovered, and the ability to ingest antibody-coated targets was comparable to that of fresh monocytes. The cells remained sterile without the use of antibiotics and were suitable for long-term culture. The monocytes that were isolated and cryopreserved by these procedures functioned reproducibly as inhibitors of tumor cell growth and in an assay of responsiveness to monocyte migration inhibitory factor (MIF).

MODULATION OF NK ACTIVITY BY RECOMBINANT LEUKOCYTE INTERFERON IN ADVANCED CANCER PATIENTS

Publisher Summary This chapter discusses modulation of natural killer (NK) activity by recombinant leukocyte interferon in advanced cancer patients. Interferons (IFN) are glycoproteins produced by certain cells after exposure to mitogens, viruses, or other agents. In vivo administration of IFN has also been reported to boost NK activity. Recently, it has been possible to clone the gene for human leukocyte A IFN, insert it into E. coli, and, thus, produce a recombinant leukocyte A IFN. A total of 108 patients were treated in two Phase I studies designed to evaluate the human tolerance, pharmacokinetic profiles and immunomodulatory effects of recombinant leukocyte A IFN. All assays were standardized for daily assay variation by the use of a set of three standards. The results of this study indicate that in vivo administration of IFN twice daily or three times weekly did not lead to an augmented NK response but instead to a diminished response in about 30% of the patients.