Jorge R. Quesada

Alpha Interferon for Induction of Remission in Hairy-Cell Leukemia

We treated seven patients who had progressive hairy-cell leukemia with daily doses of 3 million units of partially pure alpha (leukocyte) interferon by the intramuscular route. Three patients had a complete remission, and four had a partial remission, according to strict criteria for a response. After treatment, bone-marrow aspirates showed an absence of leukemia cells in three patients and 5 per cent or fewer in three others. Normalization of subnormal peripheral-blood values occurred in six of six patients with anemia, in seven of seven with granulocytopenia, and in four of four with thrombocytopenia. Remissions have been maintained for over 6 to over 10 months. Alpha interferon appears to be highly effective in patients with hairy-cell leukemia.

Clinical toxicity of interferons in cancer patients: A review

All major types of human interferons (IFNs) have been purified and clinically administered as antitumor agents. We summarize here experience to date with toxicity of IFNs in cancer patients. The acute syndrome consists of fever, chills, myalgias, arthralgias, and headache, with some variation according to type of IFN, route of administration, schedule, and dose. Fatigue, perhaps reflecting CNS toxicity, is the most prevalent nonacute symptom. At high doses, IFNs are neurotoxic; the abnormalities seen by EEG resemble those in diffuse encephalitis. Hematologic toxicity consists mainly of leukopenia, but anemia and thrombocytopenia occur in some patients. Nausea, vomiting, and diarrhea are the main gastrointestinal symptoms. Elevation of serum transaminases seems to reflect liver toxicity. Renal function is well preserved, except for rare instances of acute renal failure. Cardiac toxicity remains questionable, although heart failure and arrhythmias have been associated with the administration of IFNs. Most, if not all, of these effects are reversible or can be ameliorated. With IFN alpha, the type most widely used in clinical studies, doses of 1 million to 9 million units (MU) are generally well tolerated, but doses greater than or equal to 18 MU yield moderate to severe toxicity. Doses greater than or equal to 36 MU can induce severe toxicity and significantly alter the performance status of the patient.

Recombinant Leukocyte A Interferon: Pharmacokinetics, Single-Dose Tolerance, and Biologic Effects in Cancer Patients

Sixteen patients with advanced cancer were treated with recombinant-DNA-produced pure leukocyte A interferon (IFLrA) intramuscularly in doses ranging from 3 to 198 X 10(6) units. with interval periods of 72 to 96 hours between doses. At the two lowest doses of 3 and 9 million units, there was a cross-over evaluation between IFLrA and partially pure leukocyte interferon (IFN-C) produced from human cells. THe maximum observed serum concentration of IFLrA measured by enzyme immunoassay and bioassay increased with increasing doses. The mean serum concentrations of IFLrA and IFN-C were similar. Clinical effects produced by IFLrA and IFN-C were similar, including fever, chills, myalgias, headache fatigue, and reversible leukopenia and granulocytopenia. Eight patients had transient and mild numbness of the hands or feet, or both. Three patients developed low titers of antibody to IFLrA, Seven of 16 patients showed objective evidence of tumor regression during the study.

Antitumor activity of recombinant-derived interferon alpha in metastatic renal cell carcinoma.

Fifty-six patients with metastatic renal cell carcinoma (RCC) were treated with recombinant DNA-derived interferon alpha (rIFN alpha A). The first 30 patients were randomized between doses of 2 X 10(6) U/m2 and 20 X 10(6) U/m2 intramuscularly daily. No complete (CR) or partial (PR) remissions were achieved in 15 patients receiving the low dose. In contrast, 27% of those receiving the high dose achieved CR or PR. Subsequently, 26 additional patients were given the high dose and achieved a 31% response rate. Remissions lasted from 1 to more than 12 months (median, 3 months). Responses occurred predominantly in lung parenchyma or mediastinal node metastases. Toxicity of the high dose required dose reduction in 50% of the patients. Neutralizing antibodies to rIFN alpha A developed in seven of 12 responsive (58%) and nine of 29 (31%) nonresponsive patients (P = greater than .5). The median duration of remission among the antibody-positive and antibody-negative patients were 2 and 10 months, respectively (P = .009). The clinical significance of the antibodies to rIFN alpha A remains unclear, but the coincidence between the detection of antibodies and the early relapse of the disease in some responsive patients suggests that these antibodies may abrogate the biologic activity of rIFN alpha A. This effect, however, was not associated with adverse clinical sequelae.

PSORIASIS AND ALPHA-INTERFERON

Two patients with metastatic renal carcinoma who were treated with recombinant-DNA-derived alpha-interferon (rIFN alpha) had exacerbation of concomitant psoriasis, and another patient experienced onset of psoriasis during treatment with rIFN alpha. This suggests that interferons may participate in the pathophysiology of psoriasis.

Collaborative phase I-II study of recombinant DNA-produced leukocyte interferon (clone A) in metastatic breast cancer, malignant lymphoma, and multiple myeloma

Fifty-two patients with advanced cancer received sequentially escalating doses of 3 to 50 million units of recombinant DNA-produced alpha interferon by daily intramuscular injection. There were 23 patients with metastatic breast cancer, 17 patients with nodular poorly differentiated lymphocytic lymphoma, and 12 patients with multiple myeloma. Complete and partial remissions were obtained in 35 percent of patients with nodular poorly differentiated lymphoma, whereas rare activity was found in breast cancer and multiple myeloma. Dose-limiting toxicity occurred in patients receiving 36 million units or more and consisted of fatigue/asthenia, weight loss, and elevation of transaminase levels, requiring frequent interruption, reduction in dose, or cessation of treatment. Hematologic toxicity was rarely a limiting factor, but myelosuppression was severe in some patients with multiple myeloma. All toxicities were reversible on discontinuation of treatment. Antibodies to recombinant leukocyte A interferon were seen infrequently but may adversely affect therapy.

ANTIBODIES TO HUMAN LEUCOCYTE INTERFERONS IN CANCER PATIENTS

During the course of clinical investigation of partly purified human leucocyte interferon (IFN) prepared at the Finnish Red Cross (PIF), neutralising IgG antibodies to human leucocyte IFN were detected in the sera of 3 patients with cancer. In 2 of these patients, the antibodies were detected in serum before treatment with PIF. In the third patient antibodies developed during the course of treatment. Antibody titres against six recombinant human leucocyte IFN sub-types and one recombinant hybrid human leucocyte IFN were different in the 3 patients.

Phase II Study of Interferon Alpha in Metastatic Renal-Cell Carcinoma: A Progress Report

Partially purified interferon alpha (IFN alpha) was administered to 50 patients with metastatic renal-cell carcinoma (RCC) studied for more than two years. Complete or partial remissions were observed in 26% of the patients. Duration of remissions range from two to 16 months (median, six months). No distinct prognostic factors were clearly identified in the responsive patients, but responses occurred more frequently in men with optimal performance status who had undergone nephrectomy and in whom the metastatic disease was confined to the lungs, pleura, or mediastinum. Leukopenia and granulocytopenia were useful markers of biological activity but did not predict tumor response. Side effects and toxicity at the dosage used (3 X 10(6) units intramuscularly daily) were well-tolerated and consisted predominantly of fatigue and asthenia. We concluded that IFN alpha is useful for palliating metastatic RCC, but no impact on survival was demonstrated. Further studies are required to determine the optimal dose, routes of administration, and treatment schedules.

Phase I study of multiple dose intramuscularly administered recombinant gamma interferon.

We report the results of a phase I study of the tolerance and biologic activity of intramuscularly (IM)-administered recombinant interferon-gamma (rIFN-gamma). Forty-four patients with metastatic cancer were given rIFN-gamma at doses ranging from 0.01 to 2.5 mg/m2/d for 42 days. The most common side effects were fever, flulike symptoms, night sweats, and granulocytopenia. The maximum tolerated dose was 0.5 mg/m2/d. Administration of rIFN-gamma resulted in modulation of immune system functions, including induction of major histocompatibility complex-associated antigens on blood leukocytes, an increase in blood surface immunoglobulin-bearing B cell and natural killer (NK) cell number, and NK cell cytotoxicity. Serum lysozyme, determined as an estimate of tissue macrophage activity, also increased. Serum assays for anti-interferon antibodies were negative in all patients. Five of eight evaluable patients with lymphoproliferative disorders showed objective evidence of tumor regression consisting of partial responses (two patients), and minor responses (three patients). These data suggest that further phase II studies of IM-administered rIFN-gamma are indicated.

Treatment of hairy cell leukemia with alpha interferons.

A review of clinical research with alpha interferons in the treatment of hairy cell leukemia is presented. The results of several studies have shown that alpha interferons effectively reduce leukemic infiltrates in the bone marrow and other organswith attendant resolution of cytopenias. Alpha interferons have shown efficacy in the treatment of patients in all clinical stages of the diseaseincluding those previously untreatedand may become the treatment choice for hairy cell leukemia. Hairy cell leukemia will also provide a useful human clinical model in which some of the fundamental mechanisms of interferon activity can be studied.