Pharmacokinetic and pharmacodynamic characterization of a novel formulation containing co-formulated interferons alpha-2b and gamma in healthy male volunteers.

Background: More potent antitumor activity is desired in Interferon (IFN)-treated cancer patients. This could be achieved by combining IFN alpha and IFN gamma. The aim of this work was to characterize the pharmacokinetics and pharmacodynamics of a novel formulation containing a co-formulated combination of IFNs alpha-2b and gamma (CIGB-128-A).

Methods: A group of nine healthy male subjects received intramuscularly 24.5 × 10 IU of CIGB-128-A. IFN concentrations were evaluated for 48 h. Serum neopterin, beta2-microglobulin (βM) and 2'-5' oligoadenylate synthetase (2'-5' OAS), classical IFN-inducible serum markers, were measured during 192 h by enzyme immunoassay and body temperature was used as pharmacodynamic variable as well.

Results: Concerning pharmacokinetics, serum IFNs' profiles were better fitted to a mono-compartmental model with consecutive zero order and first order absorption, one bioavailability value. No interferences by simultaneous administered IFNs were observed in their typical similar systemic profiles. Neopterin and βM time profiles showed a delay that was efficiently linked to pharmacokinetics by means of a zero order absorption rate constant. Neopterin level was nine-fold higher than initial values, 48 h post-administration, an increment not described before. At this time, mean serum βM peaked around the double from baseline. Serum concentrations of the enzyme 2'-5' OAS was still elevated on the 8 day post-injection. The formulation was well tolerated. Most frequent adverse reactions were fever, headache, arthralgia and lymphopenia, mostly mild.

Conclusions: The administration of co-formulated IFN alpha-2b and IFN gamma likely provides improved pharmacodynamic properties that may be beneficial to treat several malignancies.

Trial Registration: Cuban Public Registry of Clinical Trials RPCEC00000118 , May 24, 2011.