The effects of a CCR3 inhibitor, AXP1275, on allergen-induced airway responses in adults with mild-to-moderate atopic asthma

BACKGROUND

CCR3 is the cognate receptor for major human eosinophil chemoattractants from the eotaxin family of proteins that are elevated in asthma and correlate with disease severity.

OBJECTIVE

This proof-of-mechanism study examined the effect of AXP1275, an oral, small-molecule inhibitor of CCR3, on airway responses to inhaled allergen challenge.

METHODS

Twenty-one subjects with mild atopic asthma and documented early and late asthmatic responses to an inhaled aeroallergen completed a randomized double-blind cross-over study to compare early and late allergen-induced asthmatic responses, methacholine PC₂₀ , blood and sputum eosinophils and exhaled nitric oxide after 2 weeks of treatment with once-daily doses of AXP1275 (50 mg) or placebo.

RESULTS

There was a significant increase in methacholine PC₂₀ after 12 days of AXP1275 treatment compared to placebo (increase of 0.92 doubling doses versus 0.17 doubling doses, P = .01), but this protection was lost post-allergen challenge. There was no effect of AXP1275 on allergen-induced late asthmatic responses, or eosinophils in blood and sputum. The early asthmatic response and exhaled nitric oxide levels were slightly lower with AXP1275, but this did not reach statistical significance. The number of subjects who experienced treatment-emergent adverse events while receiving AXP1275 was comparable placebo.

CONCLUSIONS & CLINICAL RELEVANCE

AXP1275 50 mg administered daily was safe and well tolerated, and there was no difference in the type, severity or frequency of treatment-emergent adverse events in subjects while receiving AXP1275 compared to placebo. AXP1275 increased the methacholine PC₂₀ ; however, the low and variable exposure to APX1275 over a short treatment period may have contributed to poor efficacy on other outcomes.

Design, synthesis, and biological evaluation of novel nucleoside and nucleotide analogues as agents against DNA viruses and/or retroviruses

A novel strategy was developed for the synthesis of N(7)-purine acyclic nucleosides 9 and 14. The key step involved the reaction between [2-(p-methoxyphenyloxy)ethoxy]methyl chloride and N(9)-tritylated nucleobases 6 or 11 followed by concomitant self-detritylation. N(7)-Guanine acyclic nucleoside 9 exhibited antiviral activity, but was phosphorylated by both HSV and Vero cell thymidine kinases. Thus, it showed more potent cellular toxicity than acyclovir (2). N(7)-Adenine acyclic nucleoside 14 was found to be an excellent antiviral agent as well as a good inhibitor of calf mucosal adenosine deaminase. This inhibitory property allows for a greater expression of antiviral activity of antiviral agents, such as N(9)-adenine acyclic nucleoside 1 and ara-A (3). Compound 14 was phosphorylated neither by herpes simplex virus (HSV) thymidine kinase nor by Vero cell thymidine kinase, yet it enhanced the rate constant for the monophosphorylation of acyclovir (2) by HSV thymidine kinase. Consequently, the combination of acyclovir (2) and 14 exhibited greater antiviral activity than acyclovir alone. 7-[2-(Phosphonomethoxy)ethyl]adenine (20) was also synthesized. The key step involved the reaction of 9-(2-cyanoethyl)adenine (15) with methyl iodoacetate in the presence of lithium 2,2,6,6-tetramethylpiperidine in THF. Unlike 9-[2-(phosphonomethoxy)ethyl]adenine (PMEA, 4), the N(7)-isomer 20 was not phosphorylated effectively by 5-phosphoribosyl 1-pyrophosphate synthetase (PRPP synthetase). Thus, it did not exhibit pronounced antiviral activity. Dinucleotide 5'-monophosphate 24 and its butenolide ester 25 were also synthesized. Compound 24 showed substrate activity toward PRPP synthetase and exhibited notable activity against DNA viruses. The antiviral activity of the ester derivative 25 was found to be higher than that of the parent molecule 24. Dinucleotide 5'-monophosphate 24 is susceptible to degradation by snake venom and spleen phosphodiesterases. However, its respective butenolide ester derivative 25 was completely resistant to snake venom and spleen enzymes. Butenolide ester derivatives 28 and 29 were also synthesized and exhibited notable anti-DNA virus and anti-retrovirus activity in vitro. Compounds 2, 4, 9, 14, 20, 24, 25, and 28 were also evaluated for their inhibitory effect on HSV-1-induced mortality in NMRI mice. N(7)-adenine acyclic nucleoside 14 [LD(50) (intraperitoneal, ip) 950 mg/kg], nucleotide-containing butenolide 25 [LD(50) (ip) 675 mg/kg], and butenolide 28 [LD(50) (ip) 710 mg/kg] were found to be potent anti-HSV-1 agents in vivo. In addition, butenolide 28 efficiently decreased tumor formation induced by Moloney murine sarcoma virus (MSV) in NMRI mice while significantly increasing the survival time of MSV-infected mice.

Self-sensitized photooxygenation of 3,4-dialkoxyfurans to vitamin C or its derivatives

Self-sensitized photooxygenation of 3,4-dialkoxyfurans 3a-d with molecular oxygen and UV- or sunlight at room temperature gave vitamin C derivatives 2a-d in good to excellent yields. Furan 3c, having photodegradable protecting groups, was also photooxygenated to give L-ascorbic acid (1) in a "one-pot" reaction. Furthermore, a novel photolytic transformation was developed for deuteration of furan 3b at the C-2 position with D(2)O to give furan 3d in 95% yield. Toxicity of furans 3a-c and butenolides 2a-c against human embryonic cell, murine embryo fibroblasts, normal fibroblasts, HeLa, and Vero cell lines in the presence of oxygen and indirect solar light was found to be much less than those of the antipsoriasis drugs anthralin and 8-methoxypsoralen.

Design and synthesis of a cephalosporin-retinoic acid prodrug activated by a monoclonal antibody-beta-lactamase conjugate

Two novel series of all-trans-beta-retinoic acid derivatives were synthesized and found to possess anticancer activity. The first series, cephalosporin 3'-retinoic esters 6 and 7 were, respectively, obtained by the condensation of all-trans-beta-retinoic acid (2) with cephalosporins 4 and 5. The second series, 7-(retinamido)cephalosporins 11 and 12, were synthesized, respectively, by the condensation of 2 with cephalosporins 9 and 10. These four heretofore undescribed compounds 6, 7, 11, and 12 showed inhibitory activity against murine leukemias (L1210 and P388), sarcoma 180, breast carcinoma (MCF7), and human T-lymphocytes (Molt4/C8 and CEM/0). They also inhibited squamous metaplasia and keratinization in tracheal organ cultures derived from vitamin-A-deficient hamsters. Moreover, cephalosporin 3'-retinoic ester 7 exhibited enhanced activity against keratinization with ED(50)=3.91 x 10(-11) M in the presence of a beta-lactamase from Staphylococcus aureus 95. A tumor targeting fusion protein (dsFv3-beta-lactamase) was also used in conjunction with cephem-based retinoid 7 and the potency of 7 toward L1210, P388, and MCF7 was found to approach that of the free retinoic acid (2). In the presence of dsFv3-beta-lactamase, tumor cells were found to be much more susceptible to retinoid 7 than normal human embryonic lung cells. These notions provide a new approach to the use of beta-retinoic acid for antitumor therapy.