AAPS Perspective on the EURL Recommendation on the use of Non-Animal-Derived Antibodies

In May 2020, the EU Reference Laboratory for alternatives to animal testing (EURL ECVAM) published a recommendation report entitled "Recommendation on nonanimal-derived antibodies". In this report, the EURL ECVAM specifically states: "Therefore, taking into consideration the ESAC Opinion on the scientific validity of replacements for animal-derived antibodies, EURL ECVAM recommends that animals should no longer be used for the development and production of antibodies for research, regulatory, diagnostic and therapeutic applications. The provisions of Directive 2010/63/EU should be respected, and EU countries should no longer authorise the development and production of antibodies through animal immunisation, where robust, legitimate scientific justification is lacking." (1). Here, we are providing the American Association of Pharmaceutical Scientists (AAPS) opinion on the EURL ECVAM recommendation report. In brief, there has been a clear and strong progress in reduction of animal use in the drug discovery and development process, including significant reduction of animal use in production of antibody reagents. Yet, it is proposed that more data need to be generated, shared and discussed within the scientific community before a decision to implement the change to non-animal derived antibodies is made.

Image-guided intensity modulated radiation therapy (IG-IMRT) affords increased survival for biliary tract tumors: Results from preliminary analysis

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Background: The purpose of this study is to determine the effect of image-guided radiotherapy on survival in adenocarcinoma of the biliary tract. Methods: Between 1995 and 2005, 43 pts with primary biliary tract (gallbladder or bile duct) neoplasms were treated with radiotherapy. 26 of the pts were female and 17 were male. Their average age at registration was 64, and ranged from 25 to 86. Twenty-five pts (58%) were Hispanic, while 18 (42%) were white. 31 pts (72%) underwent surgical treatment, most having cholecystecomy (50%). 29 pts (67%) had chemotherapy: 21 (72%) were given fluorouracil-based drugs, 2 (7%) received gemcitabine, and 6 (21%) received other agents. 23 pts (53%) received conventional radiation treatment using AP/PA, AP/PA with opposing lateral, or AP with opposing lateral fields. 20 pts (47%) received IG-IMRT using Nomos Peacock and daily ultrasound image guidance (BAT, Nomos, Cranberry, PA). For daily ultrasound-based image-guidance, sagittal and axial ultrasound images were acquired, and used to align pt anatomy through superimposition of CT derived organ and vascular guidance structures. Pts were treated using a boost technique to a reduced volume at gross disease after an initial dose to gross tumor and clinically evident microscopic disease. Results: Median dose to target was 54 Gy, with median conventional and IG-IMRT total doses of 48.6 and 60 Gy respectively (p=0.05). Treatment was well tolerated, with only two patients reporting RTOG grade 3 toxicity. All other patients exhibited Grade ≤2, with 23/43 reporting Grade ≤1 The median survival time from the date of registration for all patients was 8.7 months; conventional RT pts had a median survival of 6.1 months, while the IG-IMRT cohort had a median survival of 11.4 months (p = .02). Conclusions: Ultrasound-based image-guided IMRT is a feasible mechanism of delivering moderate dose escalation in conjunction with tighter safety margins, resulting in acceptable acute toxicities. Early survival data with this novel technique are encouraging and demonstrate a notable survival differential using image guided radiotherapy as component of multi-modaility regimens.

No significant financial relationships to disclose.

Inhibitors of HMG-CoA reductase sensitize human smooth muscle cells to Fas-ligand and cytokine-induced cell death

Hydroxymethylglutaryl CoA (HMG CoA) reductase inhibitors, or statins, have been shown to reduce atherosclerotic cardiovascular morbidity and mortality. Atherosclerotic plaque lesions can be chronically inflamed and vulnerable to rupture or stable and less rupture-prone. Human smooth muscle cells (SMC) are critically important in maintaining the stability of atherosclerotic plaques. This stability may be greatly influenced by pro-inflammatory mediators such as IFN-gamma, TNF-alpha, and Il-1beta and Fas ligand (FasL) that are present in human atheroma. The purpose of the present study was to examine the effect of the statins on apoptosis of SMC. We have found that SMC are normally resistant to Fas or cytokine-induced apoptosis, but can be sensitized to these agents with pharmacological concentrations of some statins. Simvastatin and lovastatin strongly sensitized the cells to apoptotic agents while atorvastatin was less effective. In contrast to the lipophilic statins, the hydrophilic statin pravastatin did not induce this sensitization of SMC to apoptosis. Treatment of SMC with either mevalonate, the product of the HMG-CoA reductase, or geranylgeranylpyrophosphate, a down stream intermediate, prevented lipophilic statin-induced sensitization to apoptosis. These results suggest that prenylation of one or more proteins is critically involved in regulating the sensitivity of SMC to apoptotic stimuli. Our data support the emerging evidence that through this pathway the various statins may have effects which are beyond a simple lowering of the levels of circulating cholesterol.

Identification of the tumor antigen 90K domains recognized by monoclonal antibodies SP2 and L3 and preparation and characterization of novel anti-90K monoclonal antibodies

The tumor antigen 90K (Mac-2BP, L3 antigen), which has been shown to have T cell costimulatory activity, is a approximately 90 kDa secreted protein found in high levels in plasma, saliva, breast milk and other human fluids. The 90K antigen can be divided into three domains: an amino terminal scavenger receptor cysteine-rich (SRCR)-like domain (D1), followed by a heavily glycosylated mucin-like domain (D2) and a approximately 27 kDa carboxy-terminal domain (D3). In this study we report on the construction of six different 90K immunoglobulin (Ig) fusion proteins containing different 90K domain combinations. Initially these fusion proteins were used to identify which 90K domain contains the epitopes recognized by the anti-90K monoclonal antibodies (mAb) SP2 and L3. Both of these mAbs were found to recognize 90K-D2. A new panel of anti-90K mAb was then generated by immunizing mice with ascites derived 90K protein. The 90K domain specific fusion proteins were then used to identify novel anti-90K mAbs which recognize the amino terminal SRCR domain and the carboxy terminal approximately 27 kDa domain of 90K. Two novel anti-90K SRCR (D1) and one anti-90 27 kDa domain (D3) mAbs were obtained. These 90K-Ig fusion proteins, as well as the novel and existing anti-90K mAbs, provide a set of tools which will allow further dissection of the structure and function of this immune modulatory protein.

Molecular cloning of a novel member of the immunoglobulin gene superfamily homologous to the polymeric immunoglobulin receptor

The CMRF35 monoclonal antibody recognizes a cell membrane antigen present on the surface of monocytes, neutrophils, a proportion of peripheral blood T and B lymphocytes and lymphocytic cell lines. Initial studies with CMRF35 suggested an unusual pattern of serological reactivity which did not correspond to any of the known leukocyte differentiation antigen clusters. We describe here the cloning and sequencing of a cDNA encoding the CMRF35 antigen by means of expression in COS cells and immunoselection with the CMRF35 monoclonal antibody. The cDNA encodes a novel integral membrane glycoprotein of 224 amino acids that represents a new member of the immunoglobulin (Ig) gene superfamily. The molecule comprises (a) a single extracellular Ig variable domain remarkably similar to the Fc receptor for polymeric IgA and IgM, (b) a membrane-proximal domain containing a high proportion of proline, serine and threonine residues that was predicted to be heavily O-glycosylated, (c) an unusual transmembrane anchor that contained a glutamic acid and a proline residue and (d) a short cytoplasmic tail. Transcripts encoding the CMRF35 protein were detected in early monocytic cell lines, in peripheral blood T cells and in some B lymphoblastoid cell lines, confirming the results of immunocytological staining. However, the level of CMRF35 expression on peripheral blood T cells was shown to decrease in response to mitogenic stimulation. The likelihood that the CMRF35 antigen shares a common evolutionary ancestor with the poly Ig Fc receptor is discussed.