[show abstract][hide abstract] ABSTRACT: The redesign of the previously reported thiophene-3-yl-methyl urea series, as a result of potential cardiotoxicity, was successfully accomplished, resulting in the identification of a novel potent series of CCR5 antagonists containing the imidazolidinylpiperidinyl scaffold. The main redesign criteria were to reduce the number of rotatable bonds and to maintain an acceptable lipophilicity to mitigate hERG inhibition. The structure-activity relationship (SAR) that was developed was used to identify compounds with the best pharmacological profile to inhibit HIV-1. As a result, five advanced compounds, 6d, 6e, 6i, 6h, and 6k, were further evaluated for receptor selectivity, antiviral activity against CCR5 using (R5) HIV-1 clinical isolates, and in vitro and in vivo safety. On the basis of these results, 6d and 6h were selected for further development.
Journal of Medicinal Chemistry 10/2013; · 5.61 Impact Factor
[show abstract][hide abstract] ABSTRACT: Preapheresis peripheral blood (PB) CD34(+) cell count is a strong predictor of hematopoietic stem cell (HSC) mobilization and is routinely used to optimize the timing, cost, and success of HSC collection in patients with multiple myeloma. However, a uniform PB CD34(+) cell count that predicts mobilization failure has not been defined, resulting in the development of institute-specific algorithms for mobilization, particularly regarding the decision of when to use the novel stem cell mobilization agent plerixafor. In this post hoc analysis, we evaluated the mobilization efficacy of plerixafor plus granulocyte colony-stimulating factor (G-CSF) versus placebo plus G-CSF in patients with multiple myeloma, stratified by preapheresis PB CD34(+) cell count: <10, <15, <20, and ≥20 cells/μL. Regardless of the PB CD34(+) cell count, the total yield of CD34(+) cells from apheresis was significantly higher in the plerixafor group than in the placebo group, and significantly more patients in the plerixafor group collected the minimum (≥2 × 10(6) cells/kg) and optimum (≥6 × 10(6) cells/kg) stem cell yields on each day of apheresis. As a corollary, the greater stem cell collection in plerixafor-treated patients resulted in the need for significantly fewer days of apheresis to reach minimum and optimum cell doses across all cell count groups. For all CD34(+) cell count groups, the proportion of patients proceeding to transplantation and the median time to platelet and neutrophil engraftment were similar in the plerixafor and placebo groups. Our findings demonstrate that in patients with multiple myeloma who might be predicted to fail mobilization based on low PB CD34(+) cell count, the addition of plerixafor to G-CSF allows for collection of the minimal and optimal cell doses in a greater proportion of patients compared with G-CSF alone. In addition, plerixafor plus G-CSF significantly improves the likelihood of optimal HSC collection in patients with higher preapheresis PB CD34(+) cell counts (≥20 cells/μL) compared with placebo plus G-CSF. Collectively, this analysis of predicted poor mobilizers validates the superiority of plerixafor plus G-CSF compared with G-CSF alone, which had been demonstrated previously in the overall patient population.
Biology of blood and marrow transplantation: journal of the American Society for Blood and Marrow Transplantation 06/2012; 18(10):1564-72. · 3.15 Impact Factor
[show abstract][hide abstract] ABSTRACT: An efficient laboratory-scale synthesis has been developed for the selective CCR5 antagonist 1. The convergent route
has a longest linear sequence of nine steps (15 steps overall), and has overall yields of 18�25%. The route has enabled the
preparation of 550 g of 1.
Organic Process Research & Development 01/2012; 16:109-116. · 2.74 Impact Factor
[show abstract][hide abstract] ABSTRACT: A series of CCR5 antagonists were optimized for potent inhibition of R5 HIV-1 replication in peripheral blood mononuclear cells. Compounds that met acceptable ADME criteria, selectivity, human plasma protein binding, potency shift in the presence of α-glycoprotein were evaluated in rat and dog pharmacokinetics.
[show abstract][hide abstract] ABSTRACT: In order to enter and infect human cells HIV must bind to CD4 in addition to either the CXCR4 or the CCR5 chemokine receptor. AMD11070 was the first orally available small molecule antagonist of CXCR4 to enter the clinic. Herein we report the molecular pharmacology of AMD11070 which is a potent inhibitor of X4 HIV-1 replication and the gp120/CXCR4 interaction. Using the CCRF-CEM T cell line that endogenously expresses CXCR4 we have demonstrated that AMD11070 is an antagonist of SDF-1α ligand binding (IC50 = 12.5 ± 1.3 nM), inhibits SDF-1 mediated calcium flux (IC50 = 9.0 ± 2.0 nM) and SDF-1α mediated activation of the CXCR4 receptor as measured by a Eu-GTP binding assay (IC50 =39.8 ± 2.5 nM) or a [(35)S]-GTPγS binding assay (IC50 =19.0 ± 4.1 nM), and inhibits SDF-1α stimulated chemotaxis (IC50 =19.0 ± 4.0 nM). AMD11070 does not inhibit calcium flux of cells expressing CXCR3, CCR1, CCR2b, CCR4, CCR5 or CCR7, or ligand binding to CXCR7 and BLT1, demonstrating selectivity for CXCR4. In addition AMD11070 is able to inhibit the SDF-1β isoform interactions with CXCR4; and N-terminal truncated variants of CXCR4 with equal potency to wild type receptor. Further mechanistic studies indicate that AMD11070 is an allosteric inhibitor of CXCR4.
[show abstract][hide abstract] ABSTRACT: The viral resistance of marketed antiviral drugs including the emergence of new viral resistance of the only marketed CCR5 entry inhibitor, maraviroc, makes it necessary to develop new CCR5 allosteric inhibitors. A mutagenesis/modeling approach was used (a) to remove the potential hERG liability in an otherwise very promising series of compounds and (b) to design a new class of compounds with an unique mutant fingerprint profile depending on residues in the N-terminus and the extracellular loop 2. On the basis of residues, which were identified by mutagenesis as key interaction sites, binding modes of compounds were derived and utilized for compound design in a prospective manner. The compounds were then synthesized, and in vitro evaluation not only showed that they had good antiviral potency but also fulfilled the requirement of low hERG inhibition, a criterion necessary because a potential approved drug would be administered chronically. This work utilized an interdisciplinary approach including medicinal chemistry, molecular biology, and computational chemistry merging the structural requirements for potency with the requirements of an acceptable in vitro profile for allosteric CCR5 inhibitors. The obtained mutant fingerprint profiles of CCR5 inhibitors were used to translate the CCR5 allosteric binding site into a general pharmacophore, which can be used for discovering new inhibitors.
Journal of the American Chemical Society 09/2011; 133(41):16477-85. · 10.68 Impact Factor
[show abstract][hide abstract] ABSTRACT: A novel series of CXCR4 antagonists were identified based on the substantial redesign of AMD070. These compounds possessed potent anti-HIV-1 activity and showed excellent pharmacokinetics in rat and dog.
[show abstract][hide abstract] ABSTRACT: Based on the attrition rate of CCR5 small molecule antagonists in the clinic the discovery and development of next generation antagonists with an improved pharmacology and safety profile is necessary. Herein, we describe a combined molecular modeling, CCR5-mediated cell fusion, and receptor site-directed mutagenesis approach to study the molecular interactions of six structurally diverse compounds (aplaviroc, maraviroc, vicriviroc, TAK-779, SCH-C and a benzyloxycarbonyl-aminopiperidin-1-yl-butane derivative) with CCR5, a coreceptor for CCR5-tropic HIV-1 strains. This is the first study using an antifusogenic assay, a model of the interaction of the gp120 envelope protein with CCR5. This assay avoids the use of radioactivity and HIV infection assays, and can be used in a high throughput mode. The assay was validated by comparison with other established CCR5 assays. Given the hydrophobic nature of the binding pocket several binding models are suggested which could prove useful in the rational drug design of new lead compounds.
[show abstract][hide abstract] ABSTRACT: A novel series of CCR5 antagonists were identified based on the redesign of Schering C. An SAR was established based on inhibition of CCR5 (RANTES) binding and these compounds exhibited potent inhibition of R5 HIV-1 replication in peripheral blood mononuclear cells.
[show abstract][hide abstract] ABSTRACT: An early lead from the AMD070 program was optimized and a structure-activity relationship was developed for a novel series of heterocyclic containing compounds. Potent CXCR4 antagonists were identified based on anti-HIV-1 activity and Ca(2+) flux inhibition that displayed good pharmacokinetics in rat and dog.
[show abstract][hide abstract] ABSTRACT: Autologous hematopoietic stem cell transplantation (ASCT) is an established treatment for patients with hematologic malignancies, yet the impact of transplanted CD34(+) cell dose on clinical outcomes is unresolved. We conducted post hoc analyses of transplanted CD34(+) cell dose and hematopoietic recovery following ASCT in 438 patients with non-Hodgkin lymphoma (NHL) or multiple myeloma (MM), using data from 2 multicenter phase 3 clinical studies that compared plerixafor plus granulocyte-colony stimulating factor (G-CSF) versus placebo plus G-CSF as stem cell mobilization regimens. Days to engraftment and the proportion of patients who reached predetermined blood count thresholds were compared across 3 CD34(+) cell dose levels: 2-4 × 10(6) cells/kg, 4-6 × 10(6) cells/kg, and >6 × 10(6) cells/kg, regardless of mobilization treatment. Short-term neutrophil and platelet engraftment times were similar regardless of cell dose. A significant linear trend was observed between transplanted CD34(+) cell dose and the proportion of patients with platelet count >150 × 10(9)/L at 100 days (P < .001), 6 months (P = .026), and 12 months (P = .020) in patients with NHL, and at 100 days in patients with MM (P = .004). A linear trend was also observed between transplanted cell dose and the proportion of patients with platelet count >100 × 10(9)/L at 100 days (P < .001) and 6 months (P = .023) in patients with NHL. A higher cell dose was associated with a lower percentage of NHL patients requiring red blood cell transfusions (P = .006). Our analyses confirm previous findings that transplanted CD34(+) cell dose may be associated with better long-term platelet recovery after ASCT.
Biology of blood and marrow transplantation: journal of the American Society for Blood and Marrow Transplantation 11/2010; 17(8):1146-53. · 3.15 Impact Factor
[show abstract][hide abstract] ABSTRACT: The redesign of azamacrocyclic CXCR4 chemokine receptor antagonists resulted in the discovery of novel, small molecule, orally bioavailable compounds that retained T-tropic (CXCR4 using, X4) anti-HIV-1 activity. A structure-activity relationship (SAR) was determined on the basis of the inhibition of replication of X4 HIV-1 NL4.3 in MT-4 cells. As a result of lead optimization, we identified (S)-N'-((1H-benzo[d]imidazol-2-yl)methyl)-N'-(5,6,7,8-tetrahydroquinolin-8-yl)butane-1,4-diamine (AMD070) 2 as a potent and selective antagonist of CXCR4 with an IC(50) value of 13 nM in a CXCR4 125I-SDF inhibition binding assay. Compound 2 inhibited the replication of T-tropic HIV-1 (NL4.3 strain) in MT-4 cells and PBMCs with an IC(50) of 2 and 26 nM, respectively, while remaining noncytotoxic to cells at concentrations exceeding 23 microM. The pharmacokinetics of 2 was evaluated in rat and dog, and good oral bioavailability was observed in both species. This compound represents the first small molecule orally bioavailable CXCR4 antagonist that was developed for the treatment of HIV-1 infection.
Journal of Medicinal Chemistry 03/2010; 53(8):3376-88. · 5.61 Impact Factor
[show abstract][hide abstract] ABSTRACT: Bis-tetraazamacrocycles such as the bicyclam AMD3100 (1) are a class of potent and selective anti-HIV-1 agents that inhibit virus replication by binding to the chemokine receptor CXCR4, the coreceptor for entry of X4 viruses. By sequential replacement and/or deletion of the amino groups within the azamacrocyclic ring systems, we have determined the minimum structural features required for potent antiviral activity in this class of compounds. All eight amino groups are not required for activity, the critical amino groups on a per ring basis are nonidentical, and the overall charge at physiological pH can be reduced without compromising potency. This approach led to the identification of several single ring azamacrocyclic analogues such as AMD3465 (3d), 36, and 40, which exhibit EC(50)'s against the cytopathic effects of HIV-1 of 9.0, 1.0, and 4.0 nM, respectively, antiviral potencies that are comparable to 1 (EC(50) against HIV-1 of 4.0 nM). More importantly, however, the key structural elements of 1 required for antiviral activity may facilitate the design of nonmacrocyclic CXCR4 antagonists suitable for HIV treatment via oral administration.
Journal of Medicinal Chemistry 02/2010; 53(3):1250-60. · 5.61 Impact Factor
[show abstract][hide abstract] ABSTRACT: Pharmacological manipulation of CXCR4 has proven clinically useful for mobilization of stem and progenitor cells and in several preclinical models of disease. It is a key component in the localization of leukocytes and stem cells. For patients with multiple myeloma and non-Hodgkin's Lymphoma, treatment with plerixafor, an inhibitor of CXCL12 binding to CXCR4, plus G-CSF mobilizes stem cells for autologous transplantation to a greater degree than the treatment with G-CSF alone, and in some cases when patients could not be mobilized with cytokines, chemotherapy, or the combination. Stem cells from healthy donors mobilized with single agent plerixafor have been used for allogeneic transplantation in acute myelogenous leukemia (AML) patients, although this is still in the early phase of clinical development. Plerixafor is also undergoing evaluation to mobilize tumor cells in patients with AML and chronic lymphocytic leukemia (CLL) to enhance the effectiveness of chemotherapy regimens. Plerixafor's effect on neutrophils may also restore circulating neutrophil counts to normal levels in patients with chronic neutropenias such as in WHIMs syndrome. Other areas where inhibition of CXCR4 may be useful based upon preclinical or clinical data include peripheral vascular disease, autoimmune diseases such as rheumatoid arthritis, pulmonary inflammation, and HIV.
Current topics in microbiology and immunology 01/2010; 341:173-91. · 4.86 Impact Factor
[show abstract][hide abstract] ABSTRACT: The redesign of azamacrocyclic CXCR4 chemokine receptor antagonists resulted in the discovery of
novel, small molecule, orally bioavailable compounds that retained T-tropic (CXCR4 using, X4) anti-
HIV-1 activity.Astructure-activity relationship (SAR) was determined on the basis of the inhibition of
replication of X4 HIV-1NL4.3 in MT-4 cells. As a result of lead optimization, we identified (S)-N0-((1Hbenzo[
d]imidazol-2-yl)methyl)-N0-(5,6,7,8-tetrahydroquinolin-8-yl)butane-1,4-diamine (AMD070) 2
as a potent and selective antagonist of CXCR4 with an IC50 value of 13 nM in a CXCR4 125I-SDF
inhibition binding assay. Compound 2 inhibited the replication of T-tropic HIV-1 (NL4.3 strain) in
MT-4 cells and PBMCs with an IC50 of 2 and 26 nM, respectively, while remaining noncytotoxic to cells
at concentrations exceeding 23 μM. The pharmacokinetics of 2 was evaluated in rat and dog, and good
oral bioavailability was observed in both species. This compound represents the first small molecule
orally bioavailable CXCR4 antagonist that was developed for the treatment of HIV-1 infection.
Journal of Medicinal Chemistry 01/2010; 53:3376-3388. · 5.61 Impact Factor