Antiproliferative properties of chemically modified recombinant IFN-alpha2b.

The antiproliferative activity of aconitylated (AIFN) and succinylated (SIFN) derivatives of recombinant interferon- alpha2b (IFN-alpha2b) was examined. Acylation of IFN-alpha2b was performed by succinic and cis-aconitic anhydrides. Antiproliferative properties of AIFN and SIFN were studied in vitro on the CaOv cell line, highly sensitive to IFN, and on the SW-480 cell line, with low sensitivity to IFN-alpha2b. Acylation of one lysine in the IFN-alpha2b molecule with cis-aconitic or succinic anhydride resulted in a 3-3.5-fold increase of its antiproliferative activity on CaOv cells. The highest antiproliferative activity of acylated IFN-alpha2b on SW-480 cells was observed for both AIFNs and SIFNs with three modified lysine residues. In conclusion, aconitylated and succinylated IFNs may be useful antiproliferative agents for cancer treatment.

Synthesis and biological properties of chimeric interferon-alpha2b peptides.

We have previously reported the antiproliferative activity of synthetic sequences 29-35 and 122-139 of the interferon-alpha2b (IFN-alpha2b), both probably representing a common receptor recognition domain. In the search of new peptidic agonists, we designed and synthesized the linear peptide (Gly)2-122-137-Gly138-Gly29-30-35-(Gly)2, in which Gly residues replaced the 138 and 29 Cys bound through a disulfide bridge in the native cytokine. Additionally, a cyclic analog was obtained by reaction of the N- and C-terminal ends of the linear fragment. Thus, the distance that separates residues 122 and 35 in the crystalline structure of the IFN-alpha2b was maintained through a (Gly)4 bridge. When the influence of chimeric peptides on the proliferation of WISH cells was studied, it was shown that both derivatives significantly diminished cell growth. A more evident inhibitory effect on (125)I-IFN-alpha2b binding to WISH cell-membrane receptors was observed for both peptides. Results indicated that chimeric IFN-alpha2b peptides behaved as partial agonists of the IFN-alpha2b molecule and may be of interest for drug design purposes.

New and modified interferon alfas: preclinical and clinical data.

Recombinant human interferon (IFN)-alpha was the first biotherapeutic agent approved by the US Food and Drug Administration for the treatment of a human malignancy. Its efficacy has also been demonstrated for treatment of several viral diseases. The human genome codes for 12 IFN-alpha proteins, with IFN alpha-1 and IFN alpha-2 accounting for the majority of the naturally occurring IFN-as. However, only subspecies of IFN alpha-2, recombinant human IFN alpha-2a and IFN alpha-2b, are commercially available in the United States. Other species of IFN-a may demonstrate equivalent or improved efficacy and have more tolerable side effects. This article describes ongoing preclinical and clinical studies of several new and modified IFN-alphas. A current phase I trial of a human recombinant IFN alpha-1 is described. Basic pharmacokinetics and clinical studies of polyethylene glycol (PEG) IFN alpha-2b are reviewed as well. Lastly, two novel types of IFN-a, one gene shuffled and one hybridized with human albumin, are summarized.

Controlled clinical trial to assess the response of recent heroin abusers with chronic hepatitis C virus infection to treatment with interferon alpha-n2b.

BACKGROUND: Chronic infection with hepatitis C virus (HCV) is the most common infectious disease among heroin abusers, but it is recommended that specific treatment with interferon be delayed until at least 6 to 12 months after the end of drug addiction. OBJECTIVE: We investigated the response of heroin abusers to interferon treatment shortly after the end of detoxification treatment with methadone. METHODS: We studied 2 homogeneous groups of white Italian patients with chronic HCV infection: former male heroin abusers and males without a history of drug addiction. Tumor necrosis factor, interleukin-1beta, interleukin-2, activated monocytes, anti-HCV antibodies, HCV RNA, and alanine aminotransferase levels were assessed. Standard treatment was initiated with 5 MU interferon alpha-n2b administered subcutaneously once daily for 8 weeks. Patients with negative HCV-RNA findings at the end of 8 weeks received further treatment with 5 MU TIW subcutaneously for an additional 48 weeks. RESULTS: Thirty of 47 patients in group A (former heroin abusers) and 30 of 30 patients in group B (controls) completed the study. Heroin abusers presented a significantly enhanced response to treatment compared with the controls. After 8 weeks, HCV-RNA test results were negative in 27 of 30 patients in group A (90.0%) and in 25 of 30 in group B (83.3%) (P = NS). Onset of relapse occurred significantly later in heroin abusers (mean [SD], 53 [3] weeks) than in controls (26 [2] weeks) (P < 0.05). Cytokine levels and activated CD11 antigen-expressing monocytes were significantly (P < 0.001) higher in heroin abusers than controls. CONCLUSION: Heroin abusers with chronic HCV infection were successfully treated with interferon alpha-n2b soon after the end of detoxification treatment.