Pharmacology of a novel, orally active PDE4 inhibitor.
BACKGROUND
Intracellular cyclic adenosine monophosphate (cAMP) in inflammatory cells and airway smooth muscle is critical to the modulation of inflammatory response generation. Phosphodiesterase 4 (PDE4), an enzyme that catalyzes cAMP degradation, is therefore being actively explored as a molecular target for the treatment of airway inflammation, particularly asthma and chronic obstructive pulmonary disease. The field has undergone major advances in optimizing generation of compounds with a safe therapeutic margin; however, most PDE4 inhibitors tested so far have unacceptable side effects, particularly nausea and vomiting.


METHODS
We evaluated NIS-62949 in a wide range of in vitro and ex vivo cell-based assays to ascertain its anti-inflammatory potential. The compound was evaluated in murine models of lipopolysaccharide-induced endotoxemia and pulmonary neutrophilia. Parameters of airway inflammation, airway hyperreactivity and bronchoconstriction were evaluated in a guinea pig model of antigen-induced allergy. In order to assess the emetic potential, the compound was evaluated biochemically for binding to high-affinity rolipram-binding site. Subsequently, the compound was tested in a surrogate model for emesis, and the results obtained were correlated directly to tests conducted in a Beagle dog model.


RESULTS
NIS-62949 is a potent, highly selective PDE4 inhibitor. The compound demonstrated potent ability to inhibit tumor necrosis factor-alpha release from human peripheral blood mononuclear cells, lymphocyte proliferation and cytokine production. The in vitro profile of NIS-62949 prompted further evaluation of the compound in vivo and the compound was found to be comparable to roflumilast in several experimental models of pulmonary inflammation. Importantly, NIS-62949 displayed a safer profile compared to roflumilast.


CONCLUSIONS
Our results report the development of a promising, novel PDE4 inhibitor, NIS-62949, with a wider therapeutic window as compared to second-generation PDE4 inhibitors such as roflumilast.
Dastidar
Sunanda G
SG
Department of Pharmacology, Ranbaxy Research Laboratories, Gurgaon, India.
Ray
Abhijit
A
Shirumalla
Rajkumar
R
Rajagopal
Deepa
D
Chaudhary
Shiwani
S
Nanda
Kamna
K
Sharma
Pawan
P
Seth
Mahesh Kumar
MK
Balachandran
Sarala
S
Gupta
Nidhi
N
Palle
Venkata
V