Robert J. Ife

The identification of clinical candidate SB-480848: a potent inhibitor of lipoprotein-associated phospholipase A2

Modification of the pyrimidone 5-substituent in clinical candidate SB-435495 has given a series of inhibitors of recombinant lipoprotein-associated phospholipase A(2) with sub-nanomolar potency. Cyclopentyl fused derivative 21, SB-480848, showed an enhanced in vitro and in vivo profile versus SB-435495 and has been selected for progression to man.

5-Aryl-pyrazolo[3,4-b]pyridazines: potent inhibitors of glycogen synthase kinase-3 (GSK-3)

Introduction of a nitrogen atom into the 6-position of a series of pyrazolo[3,4-b]pyridines led to a dramatic improvement in the potency of GSK-3 inhibition. Rationalisation of the binding mode suggested participation of a putative structural water molecule, which was subsequently confirmed by X-ray crystallography.

SB-656104-A: A novel 5-HT7 receptor antagonist with improved In vivo properties

A focused SAR study around the previously reported selective 5-HT(7) receptor antagonist, SB-269970-A has resulted in the identification of a structurally related analogue having an improved pharmacokinetic profile. Replacement of the phenolic group in SB-269970-A with an indole moiety, and replacement of the piperidinyl 4-methyl group with a heterocyclic ring system proved to be the key changes leading to the identification of SB-656104-A.

Conformationally restricted indolopiperidine derivatives as potent CCR2B receptor antagonists

The preparation and biological evaluation of a series of indolopiperidine CCR2B receptor antagonists possessing a conformationally restricted C-5 linker chain in combination with a restricted piperidine ring are described. Compared to the parent compound 1, analogue 8 shows a dramatic improvement in selectivity against a range of 5-HT and dopaminergic receptors.

Lipoprotein-associated PLA2 inhibition : a novel, non-lipid lowering strategy for atherosclerosis therapy

Lipoprotein-associated phospholipase A2 (Lp-PLA2) is a serine lipase that is associated with low density lipoprotein (LDL) in human plasma. Substrates include oxidised phosphatidylcholine (PC), which is hydrolysed by Lp-PLA2 to lyso-PC and oxidised fatty acids. Both products are bioactive and proinflammatory, and implicated in monocyte infiltration into the developing plaque, deposition of foam cells, and plaque progression and instability. Lp-PLA2 has recently been shown to be a risk factor for coronary events in previously asymptomatic, hypercholesterolaemic men. A series of azetidinones was designed as potent and selective inhibitors of this enzyme; SB-222657 inhibited release of the chemotactic cleavage products from oxidised LDL, and SB-244323 reduced atherosclerotic plaque development in a 3 month rabbit study. A series of pyrimidones has been designed from a screening hit, and nanomolar inhibitors identified. Oral efficacy in inhibiting plasma Lp-PLA2 in rabbits has been demonstrated with a variety of structural classes.

The discovery of SB-435495: A potent, orally active inhibitor of lipoprotein-Associated phospholipase A2 for evaluation in man

The introduction of a functionalised amido substituent into a series of 1-(biphenylmethylacetamido)-pyrimidones has given a series of inhibitors of recombinant lipoprotein-associated phospholipase A(2) with sub-nanomolar potency and very encouraging developability properties. Diethylaminoethyl derivative 32, SB-435495, was selected for progression to man.

Potent, orally active inhibitors of lipoprotein-associated phospholipase A2: 1-(biphenylmethylamidoalkyl)-pyrimidones

A series of 1-(biphenylmethylamidoalkyl)-pyrimidones has been designed as nanomolar inhibitors of recombinant lipoprotein-associated phospholipase A(2) with high potency in whole human plasma. 5-(Pyrazolylmethyl) derivative 16 and 5-(methoxypyrimidinylmethyl) derivative 27 demonstrated excellent pharmacodynamic profiles which correlated well with their pharmacokinetic effects.

Identification of a novel series of selective 5-HT7 receptor antagonists

Novel 5-HT(7) receptor antagonists containing the benzocycloheptanone core were identified from high throughput screening. Molecular modelling and SAR studies have converted these intractable hits into a more potent, selective and tractable series, exemplified by compound (25), SB-691673.

Identification of a sulfonamide series of CCR2 antagonists.

A series of sulfonamide CCR2 antagonists was identified by high-throughput screening. Management of molecular weight and physical properties, in particular moderation of lipophilicity and study of pK(a), yielded highly potent CCR2 antagonists exhibiting good pharmacokinetic properties and improved potency in the presence of human plasma.

1-(Arylpiperazinylamidoalkyl)-pyrimidones: orally active inhibitors of lipoprotein-associated phospholipase A2

The lipophilic 1-substituent in a series of 1-((amidolinked)-alkyl)-pyrimidones, inhibitors of recombinant lipoprotein-associated phospholipase A(2), has been modified to give inhibitors of high potency in human plasma and enhanced physicochemical properties. Phenylpiperazineacetamide derivative 23 shows very promising oral activity.