Pharmacokinetics of rhuMAb CD18, a Recombinant Humanised Monoclonal Antibody Fragment to CD18, in Normal Healthy Human Volunteers

Background and Objectives: Leucocyte β2 integrin adhesion receptors are hypothesised as a therapeutic target to modify immune responses to ischaemia-reperfusion injury that may be detrimental to recovery in a variety of disease states. Two phase I studies were designed to evaluate the pharmacokinetics, immunogenicity and safety of rhuMAb CD18, ahumanised monoclonal antibody F(ab’)₂ fragment to the CD18 receptor, in normal healthy human volunteers. Study Design and Methods: The first study evaluated six escalating doses of rhuMAb CD18 (0.06, 0.12, 0.25, 0.5, 1.0, 2.0 mg/kg) in 36 subjects given two intravenous (IV) bolus injections 12 hours apart. In the second study, 16 subjects received IV doses of 1.0 and 2.0 mg/kg as a single dose or as two doses given 12 hours apart. Study endpoints were rhuMAb CD18 serum pharmacokinetics, change in white blood cell (WBC) count, and safety and tolerability. The two studies enrolled a total of 53 subjects. Results: Serum concentration-time profiles demonstrated a monophasic decline and were best characterised by a one-compartment pharmacokinetic model. At the doses administered, the volume of distribution approximated the serum volume (range of means: 42 to 58 ml/kg). The serum clearance decreased with increasing dose until becoming consistent at doses of 0.5 to 2.0 mg/kg (range of means: 3.1 to 5.0 ml/h/kg). At doses of 0.5 to 2.0 mg/kg, the mean elimination half-life ranged from 7.0 to 9.6 hours. WBC counts increased at doses of above 0.06 mg/kg, returning to within 20% of predose values by day 7. Antibodies to rhuMAb CD18 were not detected at day 28. Mild-to-moderate adverse events were observed in both the placebo and treated groups, and were limited to flu-like symptoms. One subject experienced a serious adverse event (febrile reaction) and recovered with minimal intervention. There was no evidence of an increase in infection in subjects who received rhuMAb CD18. Conclusions: Upon IV bolus administration, rhuMAb CD18 serum concentration-time data fit a one-compartment pharmacokinetic model. At doses of 0.5 to 2.0 mg/kg, the pharmacokinetics were linear and the half-life ranged from 7.0 to 9.6 hours with a volume of distribution that approximated the serum volume. No antibodies to rhuMAb CD18 were detected. A transient, dose-dependent increase in the WBC count was observed, consistent with the expected effect of rhuMAb CD18 on leucocyte demargination. No increase in infection was observed. rhuMAb CD18 administered by IV bolus was well tolerated, with the exception of one febrile reaction.     

EEG correlates of the development of infant joint attention skills

The development of the capacity for social attention coordination, or "joint attention," is a major milestone of infancy. Data from a recent study of handicapped infants have raised the hypothesis that the tendency to initiate bids for joint attention may reflect processes associated with the frontal cortex to a greater extent than other forms of infant attention coordination (R. Caplan et al., 1993). This hypothesis was examined in a longitudinal study of 32 normally developing infants. The results indicated that EEG data at 14 months indicative of left frontal, as well as left and right central cortical activity, was associated with the tendency to initiate joint attention bids (IJA) at 14 and 18 months. In contrast, a pattern of left parietal activation and right parietal deactivation at 14 months was associated with the development of the capacity to respond to the joint attention bids (RJA) of others at 14 and 18 months. These results were interpreted to be consistent with a general anterior-posterior model of attention development (M. Posner & S. Petersen, 1990). The implications of these results for current conceptualizations of joint attention development, as well as for understanding the disturbance of joint attention skill development in autism are discussed.     

Phosphorylated KDR is expressed in the neoplastic and stromal elements of human renal tumours and shuttles from cell membrane to nucleus

Vascular endothelial growth factor (VEGF)-A is an important angiogenic factor in establishing the vasculature in renal cell carcinomas (RCCs). Since little is known about VEGF signalling in RCCs, the profile of phosphorylated KDR (pKDR) has been investigated and the intracellular location of the receptor has been examined in the present study. Using two monoclonal antibodies raised against the phosphorylated KDR epitopes (Y1059 and Y1214) known to mediate different VEGF functions, together with a commercial anti-KDR antibody and immunohistochemistry, the expression of pKDR was investigated in a series of normal (n = 25) and neoplastic kidneys (n = 54; clear cell n = 35; papillary n = 10; oncocytomas n = 8). pKDR was present in many tissue elements of both normal and neoplastic renal tissues, with strong expression in the cell membrane, cytoplasm, and nuclei of normal kidney and tumour cells, as well as endothelial cells in tumours of all histological types. Patterns and intensity were similar using both anti-pKDR antibodies. There was no significant correlation in clear cell carcinomas between pKDR expression and age (p = 0.57), tumour size (p = 0.2), gender (p = 0.59), grade (p = 0.2) or histological type (p = 0.36). To delineate further the intracellular processing that might account for the cellular distribution, confocal microscopy was also performed. Antibodies to the different phosphorylated epitopes demonstrated different intracellular staining patterns. This study shows that pKDR is present in a wide variety of renal tumours, suggesting that anti-VEGF therapy might have direct effects on tumour cells. It further suggests that cells traffic pKDR depending on the precise KDR tyrosines that are autophosphorylated in a manner that enables receptor activation to result in different functions.     

The effects of the nasal antihistamines olopatadine and azelastine in nasal allergen provocation.

BACKGROUND: Olopatadine, an antihistamine used in allergic conjunctivitis, is under development as a nasal preparation for the treatment of allergic rhinitis. OBJECTIVES: To evaluate the efficacy of olopatadine in suppressing symptoms and biomarkers of the immediate reaction induced by nasal allergen provocation and to compare olopatadine with azelastine in the same model. METHODS: The study was approved by the Johns Hopkins University institutional review board, and all subjects gave written consent. We studied 20 asymptomatic subjects with seasonal allergic rhinitis. The study had 2 randomized, double-blind, placebo-controlled, crossover phases that evaluated 2 concentrations of olopatadine, 0.1% and 0.2%. In a third exploratory phase, olopatadine, 0.1%, was compared with topical azelastine, 0.1%, in a patient-masked design. Efficacy variables were the allergen-induced sneezes, other clinical symptoms, and the levels of histamine, tryptase, albumin, lysozyme, and cysteinyl-leukotrienes (third study only) in nasal lavage fluids. RESULTS: Both concentrations of olopatadine produced significant inhibition of all nasal symptoms, compared with placebo. Olopatadine, 0.1%, inhibited lysozyme levels, but olopatadine, 0.2%, inhibited histamine, albumin, and lysozyme. The effects of olopatadine, 0.1%, were comparable to those of azelastine, 0.1%. CONCLUSIONS: Olopatadine, at 0.1% and 0.2% concentrations, was effective in suppressing allergen-induced nasal symptoms. At 0.2%, olopatadine provided evidence suggestive of inhibition of mast cell degranulation.     

Laser induced thermal injury of rabbit cornea and treatment with anti-inflammatory agents

A moderately severe thermal injury of the central cornea of 48 Dutch-belted rabbit eyes was produced with a carbon (CO₂) laser. The lesions were photographed with a slit lamp (SL) camera immediately following the injury and at 1, 2, 4, 7, 14, 21, 30 and 60 days after the exposure. Lesion size, opaqueness, and depth were graded clinically by SL biomicroscopy at the same intervals. No significant differences were found (p 0.05) between groups of eyes treated with flurbiprofen (0.03%), prednisolone acetate (1%), and vehicle control four-times-a-day for three weeks following injury. Additionally, eyes were studied histopathologically at 3 and 60 days following injury by light and transmission electron microscopy, and clinically at 30 and 60 days by endothelial specular microscopy. Important clinical and histopathological findings included coagulative necrosis of the corneal epithelium, epithelial sloughing, fusion of stromal collagen, stromal edema and inflammatory cell infiltration, stromal scar formation, corneal thinning, endothelial hyperplasia and metaplasia, fibrinous anterior chamber reaction with hypopyon, and retrocorneal fibrous membrane formation.