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Implications of Inheritance for Clinical Management: Common Cardiovascular Disorders When There Is a Family History

Reporter: Aviva Lev- Ari, PhD, RN

 

A Clinical Approach to Common Cardiovascular Disorders When There Is a Family History:  The Implications of Inheritance for Clinical Management

Srijita Sen-Chowdhry, MBBS, MD, FESC, Daniel Jacoby, MD and William J. McKenna, MD, DSc, FESC

Author Affiliations

From the Institute of Cardiovascular Science, University College London, London, United Kingdom (S.S-C., W.J.M.); Department of Epidemiology, Imperial College, London, London, United Kingdom (S.S-C.); Division of Cardiology, Yale School of Medicine, New Haven, CT (D.J., W.J.M.).

Correspondence to Professor William J. McKenna, MD, DSc, FESC, Institute of Cardiovascular Science, University College London, The Heart Hospital, 16-18 Westmoreland Street, London, E-mail william.mckenna@uclh.nhs.uk

Introduction

Since the advent of genotyping, recognition of heritable disease has been perceived as an opportunity for genetic diagnosis or new gene identification studies to advance understanding of pathogenesis. Until recently, however, clinical application of DNA-based testing was confined largely to Mendelian disorders. Even within this remit, predictive testing of relatives is cost-effective only in diseases in which the majority of families harbor mutations in known causal genes, such as adult polycystic kidney disease and hypertrophic cardiomyopathy, but not dilated cardiomyopathy. Confirmatory genetic testing of index cases with borderline clinical features may be economic in the still smaller subset of diseases with limited locus heterogeneity, such as Marfan syndrome. Furthermore, Mendelian diseases account for ≈5% of total disease burden.1 Genome-wide association studies have made headway in elucidating the genetic contribution to the more common, complex diseases, and high throughput techniques promise to facilitate integration of genetic analysis into clinical practice. Nevertheless, many genes remain to be identified and implementation of genomic profiling as a population screening tool would not be cost-effective at present. The implications of heredity, however, extend beyond serving as a platform for genetic analysis, influencing diagnosis, prognostication, and treatment of both index cases and relatives, and enabling rational targeting of genotyping resources. This review covers acquisition of a family history, evaluation of heritability and inheritance patterns, and the impact of inheritance on subsequent components of the clinical pathway.

SOURCE:

Circulation: Cardiovascular Genetics.2012; 5: 467-476

doi: 10.1161/ CIRCGENETICS.110.959361

 

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Spirogen’s Cytotoxic Warheads IP Taken over for $400 Million by AstraZeneca PLC (AZN)’s MedImmune (AZN) for Avoidance Capabilities of Emergent Drug Resistance

Reporter: Aviva Lev-Ari, PhD, RN

AstraZeneca PLC (AZN)’s MedImmune (AZN) Takes OverSpirogen Ltd. for Up to $400 Million to Bolster Oncolology Portfolio

10/15/2013 7:54:15 AM

 

AstraZeneca PLC Oncology Portfolio Strengthened as MedImmune Acquisition of Spirogen Ltd. Boosts Antibody-Drug Conjugate Capability 

AstraZeneca PLC Oncology Portfolio Strengthened as MedImmune Acquisition of Spirogen Ltd. Boosts Antibody-Drug Conjugate Capability 

Tuesday, 15 October 2013 — AstraZeneca today announced that MedImmune, its global biologics research and development arm, has acquired Spirogen, a privately-held biotech company focused on antibody-drug conjugate technology for use in oncology.

MedImmune has also entered into a collaboration agreement with ADC Therapeutics to jointly develop two of ADC Therapeutics’ antibody-drug conjugate programmes in preclinical development. MedImmune will also make an equity investment in ADC Therapeutics, which has an existing licensing agreement with Spirogen.

MedImmune will acquire 100 per cent of Spirogen’s shares for an initial consideration of $200 million and deferred consideration of up to $240 million based on reaching predetermined development milestones. Existing out-licensing agreements and associated revenue streams are excluded from this acquisition.

MedImmune will also pay $20 million for an equity investment in ADC Therapeutics, which will be matched by Auven Therapeutics, the majority shareholder in both ADC Therapeutics and Spirogen. The collaboration agreement will include an upfront payment with predetermined development milestones for two programmes from a defined list and a cost- and profit-sharing arrangement with MedImmune representing the majority share. ADC Therapeutics will also have the option to co-promote one of the products in the US.

Antibody-drug conjugates are a clinically-validated cancer drug technology that offers both high potency and selective targeting of cancer cells. Spirogen’s proprietary pyrrolobenzodiazepine (PBD) technology attaches highly potent cytotoxic agents, or ‘warheads’ to specific cancer-targeting antibodies using biodegradable ‘linkers’. This targeting optimises the delivery of the cancer drug to the tumour cells only and provides the greatest degree of tumour killing while minimising the toxicity to the patient.

“Antibody-drug conjugates are ground-breaking technologies with the potential for directly targeting many types of cancer tumours while safeguarding healthy cells. The cutting-edge technologies developed by Spirogen and ADC Therapeutics complement MedImmune’s innovative antibody engineering capabilities, enabling us to accelerate antibody-drug conjugates into the clinic,” said Dr. Bahija Jallal, Executive Vice President, MedImmune.

Oncology is a core therapy area for AstraZeneca spanning both small molecule and biologics research and development. MedImmune is developing a comprehensive portfolio with an emphasis on two key areas in oncology development: antibody-drug conjugates and immune-mediated cancer therapy, which aims to harness the power of the patient’s own immune system to fight cancer. Together, immune-mediated cancer therapies and antibody-drug conjugates have the potential to treat cancer in a way that current therapies are unable to do.

“This deal reflects the very significant progress made by our scientists, most notably over the last two years, as we have applied our warhead and linker technologies to the development of highly potent and specific antibody-drug conjugates,” said Dr. Chris Martin, Chief Executive Officer, Spirogen. “We believe that pyrrolobenzodiazepine-armed antibody-drug conjugates will emerge as a critical component in the next generation of cancer biologics with the potential to make a difference for oncologists and their patients. We look forward to combining our world-class capabilities in this area with MedImmune’s ability to develop this exciting class of oncology drugs.”

About Antibody-Drug Conjugates

An antibody-drug conjugate is a three-component system consisting of a potent cytotoxic agent, or ‘warhead’, a biodegradable linker and a monoclonal antibody. The antibody binds to specific markers at the surface of the cancer cell. The whole antibody-drug conjugate is then internalised within the cancer cell where the active drug is released. Antibody-drug conjugates have extensive potential therapeutic applications in several disease areas, particularly in cancer. The principle can also be applied beyond antibodies, with the possibility of linking warheads to antibody fragments, peptides, vitamins and hormones.

About Spirogen

The Spirogen group was founded in 2001 as a spin-out from several institutions including University College London and with partial funding by Cancer Research UK. It is majority owned by Auven Therapeutics. It has developed a novel class of highly potent cytotoxic warheads based on its proprietary pyrrolobenzodiazepines (PBDs), DNA minor groove binding agents, which bind and cross-link specific sites of DNA of the cancer cell. This blocks the cancer cells’ division without distorting its DNA helix, thus potentially avoiding the common phenomenon of emergent drug resistance. Spirogen has been developing its PBD technology for more than ten years, including a standalone PBD agent in a Phase II study in acute myeloid leukemia. Its business model has been to partner its technology with pharma and biotech for use in the development of novel drugs. It has a number of industry collaborations, including collaborations with Genentech announced in 2011 and with ADC Therapeutics announced in 2012. For further information, please visit: http://www.spirogen.com.

About ADC Therapeutics

ADC Therapeutics (ADCT) is a Swiss-based oncology drug development company that specialises in the development of proprietary antibody-drug conjugates (ADCs) targeting major cancers such as breast, lung, prostate, renal and blood. The company’s ADCs are highly targeted drug constructs which combine monoclonal antibodies specific to particular types of tumour cells with a novel class of highly potent PBD-based warheads. The company was launched in 2012 with a $50m commitment from private equity firm Auven Therapeutics. ADCT has access to warhead and linker chemistries via existing agreements with Spirogen. It operates a virtual business model based in Lausanne, Switzerland. For further information, please visit: http://www.adctherapeutics.com.

About Auven Therapeutics

Auven Therapeutics was founded by Stephen Evans-Freke and Dr. Peter B Corr in 2007 with an innovative investment strategy that enables it to operate as a drug development company while remaining structured as a private equity fund. Auven Therapeutics has a portfolio of biologic and small molecule drug candidates for a range of therapeutic indications including cancer, ophthalmic conditions, women’s health and orphan diseases. Auven manages its drug development activities from its bases in Lausanne, Switzerland, New York, USA and Hamilton, Bermuda. Auven Therapeutics Management LLLP, based in the US Virgin Islands, serves as its Investment Advisor. For further information, please visit: http://www.auventx.com.

About MedImmune

MedImmune is the worldwide biologics research and development arm of AstraZeneca. MedImmune is pioneering innovative research and exploring novel pathways across key therapeutic areas, including respiratory, inflammation and autoimmunity; cardiovascular and metabolic disease; oncology; neuroscience, and infection and vaccines. The MedImmune headquarters is located in Gaithersburg, MD, one of AstraZeneca’s three global R&D centres. For more information, please visit http://www.medimmune.com.

About AstraZeneca

AstraZeneca is a global, innovation-driven biopharmaceutical business that focuses on the discovery, development and commercialisation of prescription medicines, primarily for the treatment of cardiovascular, metabolic, respiratory, inflammation, autoimmune, oncology, infection and neuroscience diseases. AstraZeneca operates in over 100 countries and its innovative medicines are used by millions of patients worldwide. For more information please visit: http://www.astrazeneca.com

SOURCE

http://www.biospace.com/news_story.aspx?NewsEntityId=311765&type=email&source=DD_101513

 

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Reporter: Aviva Lev-Ari, PhD, RN

Prostacyclin and Nitric Oxide: Adventures in vascular biology –  a tale of two mediators

The e-Readers are encouraged to review two additional Sources on this topic on this Open Access Online Scientific Journal

Perspectives on Nitric Oxide in Disease Mechanisms

 and

Interaction of Nitric Oxide and Prostacyclin in Vascular Endothelium

S Moncada*

The Wolfson Institute for Biomedical Research, University College London, Gower Street, London WC1E 6BT, UK
* (Email: s.moncada@ucl.ac.uk)

Prof. Moncada:

I would like to thank the Royal Society for inviting me to deliver the Croonian Lecture. In so doing, the Society is adding my name to a list of very distinguished scientists who, since 1738, have preceded me in this task. This is, indeed, a great honour.

For most of my research career my main interest has been the understanding of the normal functioning of the blood vessel wall and the way this is affected in pathology. During this time, our knowledge of these subjects has grown to such an extent that many people now believe that the conquering of vascular disease is a real possibility in the foreseeable future.

My lecture concerns the discovery of two substances, prostacyclin and nitric oxide. I would like to describe the moments of insight and some of the critical experiments that contributed significantly to the uncovering of their roles in vascular biology. The process was often adventurous, hence the title of this lecture. It is the excitement of the adventure that I would like to convey in the text that follows.

Keywords: prostacyclin, aspirin, nitric oxide, oxidative stress, free radicals, cardiovascular pathology
Full article 
Philos Trans R Soc Lond B Biol Sci. 2006 May 29; 361(1469): 735–759.
Published online 2006 February 8. doi:  10.1098/rstb.2005.1775
PMCID: PMC1609404

9. THE TWO STORIES CONVERGE

Although the research fields of prostacyclin/thromboxane and NO are now mature, they have developed mostly as parallel research activities with few points of contact between them. Thus, our understanding of how both might operate in relation to each other in physiology and pathophysiology remains to be developed. Table 2 shows some of the similarities between prostacyclin and NO. Both mediators, from very different biochemical pathways, play a variety of roles in the modulation and protection of the vascular wall. The release of both mediators is dependent on constitutive enzymes, the activity of which seems to be regulated locally, predominantly by the shear stress caused by the blood passing over the endothelial surface (Grabowski et al. 1985Frangos et al. 1985; for review see Boo & Jo 2003). However, while the constitutive eNOS—localized only in the vascular endothelium—is the enzyme that responds to shear stress, the generation of prostacyclin is dependent on the activity of two enzymes, COX-1 and COX-2, in relation to which several questions remain unanswered. These include whether COX-2 is a constitutive as well as an inducible enzyme, and whether COX-1 or COX-2, or both, respond to shear stress by increases in their mRNA, their activity, or both (Topper et al. 1996Okahara et al. 1998;McCormick et al. 2000Garcia-Cardena et al. 2001). Prostacyclin, unlike NO, is constitutively generated throughout the vessel wall (Moncada et al. 1977c) and at this stage we also do not know whether the ratio between COX-1 and COX-2 changes in the different layers. In addition, the similarities and differences between regulation of NO and prostacyclin by shear stress are only now being investigated (Osanai et al. 2000McAllister et al. 2000Walshe et al. 2005).

Table 2

Table 2

Comparison of the properties of nitric oxide and prostacyclin.

A clear synergism between NO and prostacyclin has been demonstrated in regard to inhibition of platelet aggregation; however, only one of them (NO) plays a role in inhibiting platelet adhesion. The significance of this difference remains to be understood. Many years ago a physiological role for platelets in repairing the vessel wall was investigated (for discussion see Higgs et al. 1978). This subject has not been re-evaluated in the light of all this new knowledge about the roles of NO and prostacyclin in platelet/vessel wall interactions. Both mediators also regulate vascular smooth muscle proliferation and white cell vessel wall interactions through similar mechanisms which include, at least in part, the activation of adenylate cyclase and the soluble guanylate cyclase. The interactions between NO and prostacyclin in the control of these functions are not fully understood.

Both mediators are further increased by inflammatory stimuli; however, while in the case of prostacyclin the same COX-2 which responds to shear stress responds to such stimuli by a further increase in its expression, NO is generated during inflammation by a specific ‘inducible’ NO synthase which is not normally present physiologically in the vessel wall. The induction of both is inhibited by anti-inflammatory glucocorticoids (Axelrod 1983Knowles et al. 1990). It is remarkable that both compounds possess antioxidant properties (Wink et al. 1995Egan et al. 2004) but are themselves affected by oxidative stress, which inhibits the synthesis of prostacyclin and decreases the bioavailability of NO. This mechanism might be relevant to the ‘malfunctioning’ of the constitutive generation of both mediators and therefore to the genesis of endothelial dysfunction. This, however, is an early phenomenon. In advanced disease the situation is far more complex, akin to chronic inflammation in other parts of the body and, as such, probably varies significantly in the different stages of the disease. A simple hypothesis would suggest that any amount of prostacyclin which is bioavailable, although pro-inflammatory, will provide anti-thrombotic protection, while in the case of NO the balance will vary between bioavailable NO which is protective and cytotoxic peroxynitrite formed from the interaction of NO with O2. Currently, however, the results are not clear and on the crucial question of the role of both mediators in the progression of atherosclerosis, the information in relation to prostacyclin is contradictory (Burleigh et al. 2002Olesen et al. 2002Rott et al. 2003). The evidence in relation to NO, on the other hand, seems to suggest that, while constitutive NO generated by eNOS is protective (e.g. Kawashima & Yokoyama 2004), NO generated by the inducible enzyme favours the development of atherosclerosis (Chyu et al. 1999). Studies of genetically manipulated animals are providing some important clues. For example, knockout of the prostacyclin receptor (IP) leads to mice with normal blood pressure but an increased tendency to thrombosis when the endothelium is damaged (Murata et al. 1997) These animals also exhibit an increased platelet activation and proliferative response to injury that can be prevented by deletion or antagonism of the TXA2 receptor (Cheng et al. 2002). Furthermore, deletion of the IP receptor in animals prone to spontaneous atherosclerosis accelerates the development of the disease (Egan et al. 2004;Kobayashi et al. 2004). On the other hand, knocking out the thromboxane receptor or the thromboxane synthase gives rise to a mild bleeding tendency and a resistance to platelet aggregation and sudden death induced by arachidonic acid infusion (Thomas et al. 1998Yu et al. 2004). Deletion of the thromboxane receptor also seems to retard atherogenesis in murine models of atherosclerosis (Cayatte et al. 2000;Egan et al. 2005).

Although the lack of either mediator has been shown to increase the risk of thrombosis and atherosclerosis, especially in animals with additional risk factors such as ApoE deficiencies (Kuhlencordtet al. 2001Belton et al. 2003), there seems to be a certain specialization in their actions, so that NO has a more significant role in the regulation of blood pressure and blood flow, while prostacyclin has a clearer role in regulating platelet/vessel wall interactions. For example, inhibition of NO generation has an immediate and dramatic effect on blood flow and blood pressure and the eNOS−/− animal exhibits a clear hypertensive phenotype. On the other hand, inhibition of prostacyclin synthesis by the coxibs leads to a slow effect on blood pressure and apparently to a more thrombotic situation (Muscara et al. 2000;FitzGerald 2003). Similarly, COX-1−/− and COX-2−/− animals show no change in blood pressure (Norwood et al. 2000Cheung et al. 2002) and manipulation of COX or IP results in a prothrombotic phenotype.

Protection against decreases in the generation of constitutive NO and prostacyclin in the vasculature may prevent the development of vascular disease. In relation to NO, the most often tried interventions relate to the use of antioxidants (see Carr & Frei 2000) and the manipulation of eNOS expression by genetic means (Von der Leyen & Dzau 2001). Each of these interventions has shown promise in both animal experiments and in humans. An unexpected and highly interesting development relates to the effects of statins which, in the last few years, have been shown to increase the production of endothelial NO in endothelial cell cultures and in animals (for review see Laufs 2003). Many mechanisms have been claimed for this action. However, of interest in the context of our discussion is the fact that statins have been claimed to reduce oxidative stress by increasing the synthesis of BH4 (Hattori et al. 2002), increasing the coupling of the eNOS (Brouet et al. 2001) or reducing the activation of NADPH oxidase (Wagner et al. 2000). Reduction of oxidative stress is likely to preserve the generation of prostacyclin, and to our knowledge there is at least one report suggesting that statins also increase prostacyclin in endothelial cell cultures of human coronary arteries (Mueck et al. 2001). Studies on the transfection of COX-1 or COX-2 into endothelial and other cells, on the other hand, are at an early stage and clear results are not conclusive (Murakami et al. 1999Shyue et al. 2001). The full consequences of overexpression of both NO and prostacyclin in the vasculature remain to be investigated.

Also relevant to this discussion are studies of the role that NO and prostacyclin play in the protection of the cardiovascular system provided by oestrogens, and therefore in the difference between genders in susceptibility to cardiovascular disease. Oestrogens increase the expression and the activity of eNOS (Weiner et al. 1994Yang et al. 2000) and the activity of the COX-2 enzyme (Akarasereenont et al. 2000;Egan et al. 2004). They could therefore reduce oxidative stress by simply increasing both mediators. Alternatively, it has been claimed that oestrogens increase the efficiency of the NO synthase, thus reducing free radical formation (Barbacanne et al. 1999).

In summary, the concept of the balance between prostacyclin and TXA2 has to be expanded to include NO. Furthermore, although not discussed in this review, the way in which these compounds interact with many other systems known to be involved in vessel wall physiology and pathophysiology requires further investigation. Both prostacyclin and NO synergize in the protection of the vessel wall. TXA2, however, lies on the negative side of this balance being responsible for, among other things, platelet aggregation and vasoconstriction. The investigation into the interplay between these three molecules is just beginning. This is a sobering thought when one is contemplating probably close to 100 000 papers and over 30 years of research! However, it is clear that the discoveries of prostacyclin and NO have transformed our comprehension of vascular physiology and opened avenues for further understanding of pathophysiological processes. This knowledge has already benefited clinical medicine and no doubt will continue providing clues that will guide future therapy and prevention of vascular disease. I have had the good fortune to be intimately involved with both discoveries. More importantly, many of the colleagues that I have interacted with in the process of doing this work have become life-long personal friends. To those with whom I have managed to combine scientific excitement with friendship I owe a double debt of gratitude.

Philos Trans R Soc Lond B Biol Sci. 2006 May 29; 361(1469): 735–759.
Published online 2006 February 8. doi:  10.1098/rstb.2005.1775

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