The enhanced immunopharmacology of VIB4920, a novel Tn3 fusion protein and CD40L antagonist, and assessment of its safety profile in cynomolgus monkeys.

BACKGROUND AND PURPOSE: Inhibition of the T- and B-cell interaction through the CD40/CD40 ligand (L) axis is a favourable approach for inflammatory disease treatment. Clinical studies of anti-CD40L molecules in autoimmune diseases have met challenges because of thromboembolic events and adverse haemostasis. VIB4920 (formerly MEDI4920) is a novel CD40L antagonist and Tn3 fusion protein designed to prevent adverse haemostasis and immunopharmacology. We evaluated the pharmacokinetics, activity and toxicity of VIB4920 in monkeys. EXPERIMENTAL APPROACH: Cynomolgus monkeys received i.v. or s.c. 5-300 mg·kg-1 VIB4920 or vehicle, once weekly for 1 month (Studies 1 and 2) or 28 weeks (Study 3). VIB4920 exposure and bioavailability were determined using pharmacokinetic analyses, and immune cell population changes via flow cytometry. Pharmacological activity was evaluated by measuring the animals' capacity to elicit an immune response to keyhole limpet haemocyanin (KLH) and tetanus toxoid (TT). KEY RESULTS: VIB4920 demonstrated linear pharmacokinetics at multiple doses. Lymphocyte, monocyte, cytotoxic T-cell and NK cell counts were not significantly different between treatment groups. B-cell counts reduced dose-dependently and the T-cell dependent antibody response to KLH was suppressed by VIB4920 dose-dependently. The recall response to TT was similar across treatment groups. No thromboembolic events or symptoms of immune system dysfunctionality were observed. CONCLUSIONS AND IMPLICATIONS: VIB4920 demonstrated an acceptable safety profile in monkeys. VIB4920 showed favourable pharmacokinetics, dose-dependent inhibition of a neoantigen-specific immune response and no adverse effects on immune function following long-term use. Our data support the use of VIB4920 in clinical trials.

Effect of injecting primary myoblasts versus putative muscle-derived stem cells on mass and force generation in mdx mice.

It is well established that the injection of normal myoblasts or of muscle-derived stem cells (MDSCs) into the muscle of dystrophin-deficient mdx mice results in the incorporation of a number of donor myoblasts into the host muscle. However, the effect of the injected exogenous cells on mdx muscle mass and functional capacity has not been evaluated. This study evaluates the mass and functional capacity of the extensor digitorum longus (EDL) muscles of adult, male mdx mice that received intramuscular injections of primary myoblasts or of MDSCs (isolated by a preplating technique; Qu, Z., Balkir, L., van Deutekom, J.C., Robbins, P.D., Pruchnic, R., and Huard, J., J. Cell Biol. 1998;142:1257-1267) derived from normal mice. Evaluations were made 9 weeks after cell transplantation. Uninjected mdx EDL muscles have a mass 50% greater than that of age-matched C57BL/10J (normal) EDL muscles. Injections of either primary myoblasts or MDSCs have no effect on the mass of mdx EDL muscles. EDL muscles of mdx mice generate 43% more absolute twitch tension and 43% less specific tetanic tension then do EDL muscles of C57BL/10J mice. However, the absolute tetanic and specific twitch tension of mdx and C57BL/10J EDL muscles are similar. Injection of either primary myoblasts or MDSCs has no effect on the absolute or specific twitch and tetanic tensions of mdx muscle. Approximately 25% of the myofibers in mdx EDL muscles that received primary myoblasts react positively with antibody to dystrophin. There is no significant difference in the number of dystrophin-positive myofibers when MDSCs are injected. Regardless of the source of donor cells, dystrophin is limited to short distances (60-900 microm) along the length of the myofibers. This may, in part, explain the failure of cellular therapy to alter the contractile properties of murine dystrophic muscle.

Adeno-associated virus vector-mediated minidystrophin gene therapy improves dystrophic muscle contractile function in mdx mice.

Duchenne muscular dystrophy (DMD) is the most common disabling and lethal genetic muscle disorder, afflicting 1 of every 3500 males. Patients with DMD experience progressive muscle degeneration and weakness and succumb to respiratory or cardiac failure by their early twenties. No treatment is currently available for DMD. Mutations in the dystrophin gene result in lack of a functional dystrophin protein in striated muscle, which induces instability in the muscle cell membrane leading to persistent muscle injury after contraction. We have previously created novel minidystrophin genes and demonstrated that adeno-associated virus (AAV)-mediated intramuscular delivery of the minigenes effectively ameliorated mdx dystrophic histopathology and led to normal cell membrane integrity for more than 1 year. In this paper, we investigated whether AAV-minidystrophin could also improve mdx muscle contractile function. Two-month-old adult male mdx mice, with established muscular dystrophy, were given a single-dose injection of an AAV-minidystrophin vector in the tibialis anterior (TA) muscle of one leg, with the untreated contralateral leg used as a control. The treated TA muscle showed both (1) a significant increase in isometric force generation and (2) a significant increase in resistance to lengthening activation-induced muscle force decrements. We conclude that AAV-minidystrophin gene treatment is effective in improving mdx muscle contractile function.

Chloroprocaine is less painful than lidocaine for skin infiltration anesthesia.

UNLABELLED: Skin infiltration of local anesthetics causes pain. In a double-blinded protocol, 22 volunteers received random intradermal injections to the volar surface of the forearm with each of the following solutions: normal saline solution 0.9% (NSS), lidocaine 1% (L), lidocaine 1% and sodium bicarbonate 8.4% (L+BIC), 2-chloroprocaine 2% (CP), 2-chloroprocaine 2% and sodium bicarbonate 8.4% (CP+BIC), and NaCHO(3) 8.4% (BIC). Initially, each volunteer received an open-labeled injection of NSS. A 100-mm visual analog scale (VAS, 1-100) was used to assess pain with each injection. The pH of each solution was stable for the length of the study. Repeated measures of variance were used for analysis. The VAS scores (mean +/- SD) for open-label and blinded NSS injections were 15.5 +/- 15.9 and 14.0 +/- 18.1, respectively. The scores for the studied solutions were as follows: BIC, 47.2 +/- 25.5; L, 25.8 +/- 27.6; L+BIC, 16.0 +/- 14.2; CP, 8.6 +/- 7.4; and CP+BIC, 6.8 +/- 6.7. No significant difference was found between CP and alkalinized CP, but the injection of both solutions was significantly less painful than that of all other solutions (P < 0.05). The pH of the solutions was not related to the pain score. We found that chloroprocaine caused less pain at injection than the more commonly used lidocaine. IMPLICATIONS: Using 2-chloroprocaine can diminish pain caused by the intradermal injection of lidocaine. pH variations of the solution did not relate to the pain profile of the local anesthetic.