Response to intermediate and standard doses of IFN-beta in hairy-cell leukaemia

Long term results of interferon treatment in hairy cell leukemia. Italian Cooperative Group of Hairy Cell Leukemia (ICGHCL)

Eighty nine of 104 patients with hairy cell leukemia (HCL), enrolled between 1985 and 1987 in a multicenter prospective study on human lymphoblastoid IFN alpha-n1, were evaluable for long-term follow-up. The induction treatment, 3 MU/mq daily for a median of 5.7 months, produced a response of 93%, complete+partial response (CR+PR) = 80%, minor (MR) = 13%. Neither prior splenectomy nor pre-treatment variables were associated with the rate of response to IFN. However maintenance treatment of 3 MU/mq weekly given randomly had a slightly significant effect on failure free survival (FFS). Of the 43 patients who relapsed, 31/36 (86%) obtained a new response with IFN. No differences in FFS were recorded between first and second response. At the third induction 7/11 patients were treated again with IFN, 4/7 obtaining some response, but the FFS was significantly worse. The overall survival is still 85%. We conclude that (1) IFN should be used as chronic uninterrupted treatment for HCL, (2) reduced dosage is sufficient to prolong the disease free status and (3) continuous lymphoblastoid IFN administration seems not to be associated with the development of resistance to retreatment.

Double-blind randomized phase I study on the clinical tolerance and pharmacodynamics of natural and recombinant interferon-beta given intravenously

The clinical tolerance and biological properties of 6 x 10(6) IU of Chinese hamster glycosylated recombinant interferon-beta (rHuIFN-beta) and natural IFN-beta (Frone) given i.v. were compared in 12 healthy volunteers in a randomized cross-over, double-blind trial. All subjects received a single injection of each type of IFN-beta. Both were well tolerated and provoked similar changes in clinical indices. Serum neopterin (Np) values increased significantly from the 24th to 72nd h post-injection of rHuIFN-beta and Frone. beta 2-Microglobulin (beta 2-M) serum levels were statistically above baseline 24-96 h after rHuIFN-beta, and from the 24th to the 120th h with Frone. Both IFNs provoked a rise in intracellular 2',5'-adenylate (2-5A) levels from the 10th to the 48th h, as well as in Hu-Mx synthesis, which was significant from the 10th to the 96th h. Serum levels of 2-5A, interleukin-1 alpha (IL-1 alpha), and interleukin-1 beta (IL-1 beta) remained unchanged. There were no statistical differences in the changes provoked by the two differently derived IFN-beta in any of the biological parameters studied. Overall, the results of this study indicate that rHuIFN-beta and Frone have similar pharmacodynamics.

Double-blind randomized phase I study on the clinical tolerance and biological effects of natural and recombinant interferon-beta

The clinical tolerance of and the effects recombinant human interferon-beta (rHuIFN-beta) obtained from mammalian cells (Chinese hamster ovary cells) exerts on 2',5'-oligoadenyl (2-5A) synthetase activity, human-Mx protein, neopterin, beta 2-microglobulin, interleukin-1 (IL-1) alpha and beta synthesis were compared to those of natural IFN-beta in 12 healthy volunteers. Each subject received a single i.m. injection of 6 x 10(6) IU rHuIFN-beta and natural IFN-beta according to a randomized double-blind cross-over study design. Both were well tolerated and provoked similar changes in clinical indices. Moreover, rHuIFN-beta and natural IFN-beta induced significant and similar increases in 2'-5' adenylates, human Mx protein, and neopterin levels, but neither modulated beta 2-microglobulin, IL-1 alpha or beta synthesis. The sum of these findings indicates that rHuIFN-beta and natural IFN-beta are biologically equivalent. In view of these results, we are of the opinion that these two types of IFN are probably also therapeutically equivalent and, in consequence, that trials to evaluate the response of viral and neoplastic disease patients to rHuIFN-beta are fully justified.

Biochemical and immunological responses of hairy cell leukemia patients to interferon beta

Ten hairy-cell leukemia patients were treated with interferon beta (IFN-beta) at a dose rate of 2 x 10(6) IU/m2 x 5 days for 4 weeks (induction therapy) and, thereafter, at the same dose three times a week for 11 months (maintenance therapy). The effect of this treatment on serum neopterin, beta 2-microglobulin, (2'-5')oligoadenylate [(2'-5')An] levels, intracellular (2'-5')An values and human Mx protein synthesis was analysed. There were significant rises in serum neopterin and (2'-5')An levels during both induction and maintenance, whereas beta 2-microglobulin levels rose only during induction. Rises in intracellular (2'-5')An were documented mainly during induction, but they were not significantly higher than pretherapy values. IFN beta provoked an increase in human Mx protein synthesis over the entire induction-maintenance period, but was only significantly higher than baseline during induction. All markers proved useful for monitoring the effects of IFN beta dose schedules, but were not predictive of clinical outcome. Natural killer activity and IFN gamma production, which were initially defective, followed a different trend from that of the other factors studied, in that increases were documented only late in the course of therapy when the disease was already in remission.

Selection of a panel of monoclonal antibodies for monitoring residual disease in peripheral blood and bone marrow of interferon-treated hairy cell leukaemia patients

A panel of monoclonal antibodies (mAbs) directed against B-cell and hairy cell leukaemia (HCL)-associated antigens was used to identify residual hairy cells in the peripheral blood and/or bone marrow samples from 20 patients with HCL, following treatment with interferon-alpha (IFN-alpha) or interferon-beta (IFN-beta). In all cases, hairy cells retained their characteristic phenotype, e.g. positivity for CD22, CD11c, CD25, CD32, and the HCL-associated trimeric protein (t-GP) recognized by the mAbs HML-1, B-ly7, LF61 and Ber-Act8. The most specific marker for identifying a small percentage of hairy cells in peripheral blood cytospins, was t-GP. In alkaline phosphatase/anti alkaline phosphatase (APAAP) stained preparations, t-GP+ hairy cells (provided with large cytoplasm and hairy surface) could be usually distinguished from t-GP+ normal lymphocytes (small-sized cells with smooth surface). In doubtful cases the percentage of residual hairy cells could exactly be estimated by double immunofluorescence staining for CD22 (B-cell marker) and t-GP. The rationale of the test is based on the finding that the small percentage (about 1%) of t-GP+ lymphocytes circulating in the peripheral blood of normal individuals are T-cells of the CD8 subset and not B-cells. The best markers for identifying residual hairy cells in routine bone marrow biopsies were CD45RA (mAb 4KB5) and CD20 (mAb L26). Immunohistological labelling was superior to morphological examination in picking up scattered hairy cells in bone marrow biopsies showing either severe hypoplasia or exuberant hyperplasia of normal haemopoietic series.