Bhami C. Shenoy

Crystalline monoclonal antibodies for subcutaneous delivery

Therapeutic applications for mAbs have increased dramatically in recent years, but the large quantities required for clinical efficacy have limited the options that might be used for administration and thus have placed certain limitations on the use of these agents. We present an approach that allows for s.c. delivery of a small volume of a highly concentrated form of mAbs. Batch crystallization of three Ab-based therapeutics, rituximab, trastuzumab, and infliximab, provided products in high yield, with no detectable alteration to these proteins and with full retention of their biological activity in vitro. Administration s.c. of a crystalline preparation resulted in a remarkably long pharmacokinetic serum profile and a dose-dependent inhibition of tumor growth in nude mice bearing BT-474 xenografts (human breast cancer cells) in vivo. Overall, this approach of generating high-concentration, low-viscosity crystalline preparations of therapeutic Abs should lead to improved ease of administration and patient compliance, thus providing new opportunities for the biotechnology industry.

Hyperoxaluria Is Reduced and Nephrocalcinosis Prevented with an Oxalate-Degrading Enzyme in Mice with Hyperoxaluria

Background/Aims: Hyperoxaluria is a major risk factor for recurrent urolithiasis and nephrocalcinosis. We tested an oral therapy with a crystalline, cross-linked formulation of oxalate-decarboxylase (OxDc-CLEC®) on the reduction of urinary oxalate and decrease in the severity of kidney injury in two models: AGT1 knockout mice (AGT1KO) in which hyperoxaluria is the result of an Agxt gene deficiency, and in AGT1KO mice challenged with ethylene glycol (EG). Methods: Four different doses of OxDc-CLEC mixed with the food, or placebo were given to AGT1KO mice (200 mg/day, n = 7) for 16 days and to EG-AGT1KO mice (5, 25, and 80 mg, n = 11) for 32 days. Results: Oral therapy with 200 mg OxDc-CLEC reduced both urinary (44%) and fecal oxalate (72%) in AGT1KO mice when compared to controls. Similarly, in EG-AGT1KO mice, each of the three doses of OxDc-CLEC produced a 30–50% reduction in hyperoxaluria. A sustained urinary oxalate reduction of 40% or more in the 80 mg group led to 100% animal survival and complete prevention of nephrocalcinosis and urolithiasis. Conclusion: These data suggest that oral therapy with OxDc-CLEC may reduce hyperoxaluria, prevent calcium oxalate nephrocalcinosis and urolithiasis, and can represent a realistic option for the treatment of human hyperoxaluria, independent of cause.

Cystals and cross-linked enzyme crystals (CLEC)of fungal and bacterial lipases and correction of canine pancreatic steatorrhea

Background: The exolipase of Burkholderia plantarii has a high specific activity and corrects canine pancreatic steatorrhea when dogs are fed a high fat diet (GE 1997;112:2048 & 1999;116:431). We hypothesized that crystals and CLECs of lipases from other organisms would exhibit a high specific activity (~5000 IV/mg vs ~30 IV/mg for porcine lipase) and correct pancreatic steatorrhea. Further, CLECs might stabilize lipase against inactivation by acid, proteolytic enzymes and by the presence of bile acids. Aims: To compare the effects of crystals and cross-linked lipases of Candida rugosa (CR) and Burkholderia cepacia (BC) with B. plantarii (BL) on fat absorption in dogs with exocrine pancreatic insufficiency. Methods: Four dogs underwent ligation of major and minor pancreatic ducts. The coefficient of fat absorption (CFA) was measured by 72-hr fecal balance studies before and after operation and 3 wk after operation with 300,000 IV of BL or 600,000 IV of lipolytic activity of CR and BC lipases. During these studies, dogs ingested a high fat diet (43% fat, 36% protein and 21% CHO as % of calories [1700 kCal/d)). ANOVA and post hoc t-tests with Bonferonni correction were used to determine if there were significant differences among treatments. Results: CFA was significantly different among treatments (ANOVA, p<O.OOOOI) and the CFA was significantly greater (p<0.05) compared to no treatment (control postop) when the dogs were given crystalline CR, crystalline BC, crosslinked BC or BL (table). Conclusions: Crystal forms of CR and PC and CLECs of BC are as effective as BL in reducing pancreatic steatorrhea and are candidate lipases for treating human pancreatic steatorrhea.