Development of a long acting human growth hormone analog suitable for once a week dosing.

Human growth hormone was conjugated to a carrier aldolase antibody, using a novel linker by connecting a disulphide bond in growth hormone to a lysine-94 amine located on the Fab arm of the antibody. The resulting CovX body showed reduced affinity towards human growth hormone receptor, reduced cell-based activity, but improved pharmacodynamic properties. We have demonstrated that this CovX-body, given once a week, showed comparable activity as growth hormone given daily in an in vivo hypophysectomized rat model.

Development of novel linkers to conjugate pharmacophores to a carrier antibody.

We have developed modified maleimide novel linkers with improved chemical stability that could potentially be used in conjugating various pharmacophores such as oligo nucleotides, peptides, and proteins to antibodies to afford novel biologics with well-defined therapeutic benefits and improved pharmacokinetic properties. These linkers expand the array of tools available for bioconjugation of pharmacophores to antibodies.

Inhibitors of ABL and the ABL-T315I mutation.

Chronic myelogenous leukemia (CML) is a hematological stem cell disorder caused by increased and unregulated growth of myeloid cells in the bone marrow, and the accumulation of excessive white blood cells. Abelson tyrosine kinase (ABL) is a non-receptor tyrosine kinase involved in cell growth and proliferation and is usually under tight control. However, 95% of CML patients have the ABL gene from chromosome 9 fused with the breakpoint cluster (BCR) gene from chromosome 22, resulting in a short chromosome known as the Philadelphia chromosome. This Philadelphia chromosome is responsible for the production of BCR-ABL, a constitutively active tyrosine kinase that causes uncontrolled cellular proliferation. An ABL inhibitor, imatinib, was approved by the FDA for the treatment of CML, and is currently used as first line therapy. However, a high percentage of clinical relapse has been observed due to long term treatment with imatinib. A majority of these relapsed patients have several point mutations at and around the ATP binding pocket of the ABL kinase domain in BCR-ABL. In order to address the resistance of mutated BCR-ABL to imatinib, 2(nd) generation inhibitors such as dasatinib, and nilotinib were developed. These compounds were approved for the treatment of CML patients who are resistant to imatinib. All of the BCR-ABL mutants are inhibited by the 2(nd) generation inhibitors with the exception of the T315I mutant. Several 3(rd) generation inhibitors such as AP24534, VX-680 (MK-0457), PHA-739358, PPY-A, XL-228, SGX-70393, FTY720 and TG101113 are being developed to target the T315I mutation. The early results from these compounds are encouraging and it is anticipated that physicians will have additional drugs at their disposal for the treatment of patients with the mutated BCR-ABL-T315I. The success of these inhibitors has greater implication not only in CML, but also in other diseases driven by kinases where the mutated gatekeeper residue plays a major role.

Development of prodrug 4-chloro-3-(5-methyl-3-{[4-(2-pyrrolidin-1-ylethoxy)phenyl]amino}-1,2,4-benzotriazin-7-yl)phenyl benzoate (TG100801): a topically administered therapeutic candidate in clinical trials for the treatment of age-related macular degeneration.

Age-related macular degeneration (AMD) is one of the leading causes of loss of vision in the industrialized world. Attenuating the VEGF signal in the eye to treat AMD has been validated clinically. A large body of evidence suggests that inhibitors targeting the VEGFr pathway may be effective for the treatment of AMD. Recent studies using Src/YES knockout mice suggest that along with VEGF, Src and YES play a crucial role in vascular leak and might be useful in treating edema associated with AMD. Therefore, we have developed several potent benzotriazine inhibitors designed to target VEGFr2, Src, and YES. One of the most potent compounds is 4-chloro-3-{5-methyl-3-[4-(2-pyrrolidin-1-yl-ethoxy)phenylamino]benzo[1,2,4]triazin-7-yl}phenol ( 5), a dual inhibitor of both VEGFr2 and the Src family (Src and YES) kinases. Several ester analogues of 5 were prepared as prodrugs to improve the concentration of 5 at the back of the eye after topical administration. The thermal stability of these esters was studied, and it was found that benzoyl and substituted benzoyl esters of 5 showed good thermal stability. The hydrolysis rates of these prodrugs were studied to analyze their ability to undergo conversion to 5 in vivo so that appropriate concentrations of 5 are available in the back-of-the-eye tissues. From these studies, we identified 4-chloro-3-(5-methyl-3-{[4-(2-pyrrolidin-1-ylethoxy)phenyl]amino}-1,2,4-benzotriazin-7-yl)phenyl benzoate ( 12), a topically administered prodrug delivered as an eye drop that is readily converted to the active compound 5 in the eye. This topically delivered compound exhibited excellent ocular pharmacokinetics and poor systemic circulation and showed good efficacy in the laser induced choroidal neovascularization model. On the basis of its superior profile, compound 12 was advanced. It is currently in a clinical trial as a first in class, VEGFr2 targeting, topically applied compound for the treatment of AMD.

Inhibition of nuclear factor-kappaB in T cells suppresses lung fibrosis.

RATIONALE: Cytokines secreted by T cells play a pivotal role in the pathogenesis of lung injury and fibrosis, and the transcription factors nuclear factor (NF)-kappaB and activator protein (AP)-1 are involved in the expression of cytokines from T cells during lung injury. OBJECTIVES: We assessed the potential therapeutic effect of SP100030, a specific inhibitor of T-cell NF-kappaB and AP-1 in lung fibrosis. METHODS: The effect of SP100030 was evaluated using a mouse model of chronic lung fibrosis. MEASUREMENTS AND MAIN RESULTS: Mice treated with SP100030, as compared with untreated mice, had significantly less cachexia and less lung injury and had decreased levels of inflammatory cytokines and growth factors, decreased activation of coagulation activation, and decreased collagen deposition in the lung. The inhibitory activity of SP100030 was dose dependent and was effective in acute and chronic phases of lung fibrosis. SP100030 inhibited the activation of the protein kinase C-isoform in T-cell lines and suppressed NF-kappaB-driven cytokine expression in CD4(+) and CD8(+) T cells. CONCLUSIONS: These results suggest that the specific inhibition of NF-kappaB could be useful for the treatment of lung fibrosis.

The design and preliminary structure-activity relationship studies of benzotriazines as potent inhibitors of Abl and Abl-T315I enzymes.

We describe the design, synthesis and structure-activity relationship studies in optimizing a series of benzotriazine compounds as potent inhibitors of both Abl and Abl-T315I enzymes. The design includes targeting of an acid functional residue on the alphaC-helix that is available only upon kinase activation. This designed interaction provides an advantage in overcoming the challenges arising from the T315I mutation of Abl and transforms poor (ca. 10 microM) inhibitors into those with low nM potency.

Discovery of 3,3'-(2,4-diaminopteridine-6,7-diyl)diphenol as an isozyme-selective inhibitor of PI3K for the treatment of ischemia reperfusion injury associated with myocardial infarction.

In studies aimed toward identifying effective and safe inhibitors of kinase signaling cascades that underlie ischemia/reperfusion (I/R) injury, we synthesized a series of pteridines and pyridopyrazines. The design strategy was inspired by the examination of naturally occurring PI3K inhibitors such as wortmannin and quercetin, and building a pharmacophore-based model used for optimization. Structural modifications led to hybrid molecules which incorporated aminopyrimidine and aminopyridine moieties with ATP mimetic characteristics into the pharmacophore motifs to modulate kinase affinity and selectivity. Elaborations involving substitutions of the 2 and 4 positions of the pyrimidine or pyridine ring and the 6 and 7 positions of the central pyrazine ring resulted in in vivo activity profiles which identified potent inhibitors of vascular endothelial growth factor (VEGF) induced vascular leakage. Pathway analysis identified a diaminopteridine-diphenol as a potent and selective phosphatidylinositol-3-kinase (PI3K) inhibitor. The structure-activity relationship studies of various analogues of diaminopteridine-diphenol-based on biochemical assays resulted in potent inhibitors of PI3K.

Discovery of [7-(2,6-dichlorophenyl)-5-methylbenzo [1,2,4]triazin-3-yl]-[4-(2-pyrrolidin-1-ylethoxy)phenyl]amine--a potent, orally active Src kinase inhibitor with anti-tumor activity in preclinical assays.

We describe the identification of [7-(2,6-dichlorophenyl)-5-methylbenzo [1,2,4]triazin-3-yl]-[4-(2-pyrrolidin-1-ylethoxy)phenyl]amine (3), a potent, orally active Src inhibitor with desirable PK properties, demonstrated activity in human tumor cell lines and in animal models of tumor growth.

Discovery and preliminary structure-activity relationship studies of novel benzotriazine based compounds as Src inhibitors.

We report the discovery and preliminary SAR studies of a series of structurally novel benzotriazine core based small molecules as inhibitors of Src kinase. To the best of our knowledge, benzotriazine template based compounds have not been reported as kinase inhibitors. The 3-(2-(1-pyrrolidinyl)ethoxy)phenyl analogue (43) was identified as one of the most potent inhibitors of Src kinase.

The design and synthesis of novel orally active inhibitors of AP-1 and NF-kappaB mediated transcriptional activation. SAR of in vitro and in vivo studies.

We have developed novel orally active quinazoline analogues as inhibitors of AP-1 and NF-kappaB mediated transcriptional activation. Among the derivatives prepared, 1-[2-(2-thienyl)quinazolin-4-ylamino]-3-methyl-3-pyrroline-2,5-dione (10) showed significant activity in an adjuvant-induced arthritis rat model by reducing the swelling by 65% in the non-injected foot. The synthesis, structure-activity relationship, and in vivo activity are described.

Structure-activity relationship studies of ethyl 2-[(3-methyl-2,5-dioxo(3-pyrrolinyl))amino]-4-(trifluoromethyl)pyrimidine-5-carboxylate: an inhibitor of AP-1 and NF-kappaB mediated gene expression.

Several analogues of ethyl 2-[(3-methyl-2,5-dioxo(3-pyrrolinyl))amino]-4-(trifluoromethyl)pyrimidine-5-carboxylate (1) were synthesized and tested as inhibitors of AP-1 and NF-kappaB mediated transcriptional activation in Jurkat T cells. From our SAR work, ethyl 2-[(3-methyl-2,5-dioxo(3-pyrrolinyl))-N-methylamino]-4-(trifluoromethyl)-pyrimidine-5-carboxylate was identified as a novel and potent inhibitor.

Inhibitors of AP-1 and NF-kappa B mediated transcriptional activation: therapeutic potential in autoimmune diseases and structural diversity.

Cytokines and chemokines play a very important role in a number of inflammatory diseases. In activated T cells, transcription factors such as the activator protein-1 (AP-1) regulate IL-2 production and production of matrix metalloproteinases, the nuclear factor kappa B (NF-kappa B) is essential for the transcriptional regulation of the proinflammatory cytokines IL-1, IL-6, IL-8 and TNF alpha, and nuclear factor of activated T-cells (NFAT) is required for the transcriptional regulation of IL-2, IL-3, IL-4, IL-5, IL-8, IL-13, TNF alpha, and GM-CSF. During the last few years, several groups have developed inhibitors of AP-1, NF-kappa B or both, and NFAT. This review article presents the recent progress in the development of inhibitors for AP-1, NF-kappa B, and NFAT mediated transcriptional activation.