C.D. Johnson and C.W. Imrie
`
`Pancreatic Disease
`
`l
`
`Basic Science and Clinical Management
`
`With 82 Figures
`
`'Springer
`
`Roxane Labs., Inc.
`Exhibit 1013
`Page 001
`
`

`
`C.D. Johnson, MChir, FRCS
`University Surgical Unit
`Southampton General Hospital
`Southampton, UK
`
`C.W. Imrie, BSc, MB, FRCS
`Royal Infirmary
`Glasgow, UK
`
`British Library Cataloguing in Publication Data
`Pancreatic disease: basic science and clinical management
`I. Pancreas - Diseases 2. Pancreas -Cancer 3. Pancreatitis
`!. johnson, C.D. (Colin David), 1952- II. Imrie, C.W.
`(Clement William)
`616.3'7
`ISBN 1852337117
`
`Library of Congress Cataloging-in-Publication Data
`Pancreatic disease: basic science and clinical management/ C. D. johnson and
`C.W. Imrie (eds).
`p.;cm.
`Includes bibliographical references.
`ISBN 1-85233-711-7 (alk. paper)
`1. Pancreas-Diseases. !. Title: Pancreatic disease in the twenty-first century. II.
`johnson, C. D. (Colin David), 1952- III. Imrie, C. W.
`[DNLM: 1. Pancreatic Diseases-diagnosis. 2. Pancreatic Diseases-etiology. 3. Pancreatic
`Diseases-therapy. 4. Therapies, Investigational. WI 800 P1892 2004)
`RC857.P3225 2004
`616.3'7 -dc21
`
`2003054423
`
`Apart from any fair dealing for the purposes of research or private study, or criticism or
`review, as permitted under the Copyright, Designs and Patents Act 1988, this publication
`may only be reproduced, stored or transmitted, in any form or by any means, with the
`prior permission in writing of the publishers, or in the case of reprographic reproduc(cid:173)
`tion in accordance with the terms of licences issued by the Copyright Licensing Agency.
`Enquiries concerning reproduction outside those terms should be sent to the publishers.
`
`ISBN 1-85233-711-7 Springer-Verlag London Berlin Heidelberg
`Springer-Verlag is a part of Springer Science+ Business Media
`springeronline.com
`
`© Springer-Verlag London Limited 2004
`Printed in Singapore
`
`The use of registered names, trademarks, etc. in this publication does not imply, even in
`the absence of a specific statement, that such names are exempt from the relevant laws
`and regulations and therefore free for general use.
`
`Product liability: The publisher can give no guarantee for information about drug
`dosage and application thereof contained in this book. In every individual case th e
`respective user must check its accuracy by consulting other pharmaceutical literature.
`
`Typeset by EXPO Holdings, Malaysia
`28/3830-543210 Printed on acid-free paper SPIN 10900925
`
`Roxane Labs., Inc.
`Exhibit 1013
`Page 002
`
`

`
`Neuroendocrine Tumours
`
`Roxane Labs., Inc.
`Exhibit 1013
`Page 003
`
`

`
`4 Gl Hormone Producing Tumours: Syndromes and
`Treatment Options
`Mary McStay and Martyn E. Caplin
`
`Neuroendocrine tumours of the pancreas (also called pancreatic endocrine
`tumours or islet cell tumours) may be functioning or non-functioning. Functioning
`tumours are those associated with a clinical syndrome that is caused by hormone
`release, and are named according to the hormone that they secrete (Table 4.1).
`Non-functioning neuroendocrine tumours of the pancreas include those that have
`all the histological characteristics of a neuroendocrine pancreatic tumour (NPT),
`but no associated clinical syndrome related to hormone hypersecretion. NPTs are
`rare tumours, with an incidence of less than 1/100 000 population/year. Non(cid:173)
`functioning tumours form the biggest group (30-40%), followed by gastrinomas
`and insulinomas, which have approximately the same incidence. With the
`exception of insulinomas, the majority of NPTs are malignant.
`Eight of the NPTs are well established and are included in most classifications.
`These are gastrinomas, insulinomas, VIPomas, glucagonomas, somatostatinomas,
`growth-hormone releasing factor secreting tumours (GRFomas), ACTH secreting
`tumours of the pancreas (ACTHomas), and 'non-functioning' tumours, which may in
`fact be pancreatic polypeptide-secreting tumours (PPomas). Other rarer NPTs have
`recently been considered as causing syndromes, including NPTs causing hypercal(cid:173)
`caemia (producing parathyroid hormone and parathyroid hormone-related protein),
`NPTs secreting calcitonin and NPTs causing the carcinoid syndrome.
`
`Pathophysiology and Pathology of Neuroendocrine Tumours
`
`The histological diagnosis of neuroendocrine tumours relies first on the
`identification of general markers of neuroendocrine differentiation, and then cell(cid:173)
`specific characterisation. Neuroendocrine differentiation is evaluated by immuno(cid:173)
`histochemistry using antibodies against secretory granule proteins ( chromogranin
`A, synaptophysin) and cytosolic proteins (neuron-specific enolase, protein gene
`product 9.5). The cell-specific characterization of neuroendocrine tumours
`requires hormone immunohistochemistry. According to the World Health
`Organisation (WHO) classification, neuroendocrine tumours of the gastroen(cid:173)
`teropancreatic tract are classified as well-differentiated and poorly differentiated
`depending on their histological and functional features.
`
`31
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`Roxane Labs., Inc.
`Exhibit 1013
`Page 004
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`

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`Table 4.1. The different types of pancreati c neuroendocrine tumours and their associated hyperfunctional synd romes
`Predominant hormone
`Major clinical symptoms
`Tumour location
`Cell type
`Tumour
`Recurrent peptic ulcer
`Pancreas 50%
`Gastrinomas
`G
`Gastrin
`Duodenum 50%
`Pancreas
`
`B
`
`?
`
`A
`
`D
`
`?
`
`lnsulinoma
`
`V!Poma
`
`Glucagonoma
`
`Somatostatinoma
`
`GR Foma
`
`ACTHoma
`PPoma
`
`Insulin
`
`Vasoactive intestinal
`polypeptide (VIP)
`Glucago n
`
`Somatostatin
`
`Hypoglycaemia (fasting or
`nocturnal)
`Watery diarrhoea, hypokalaemia,
`achlorhydria
`Diabetes mellitus, necrolytic
`migratory erythema
`Diabetes mellitus
`
`Growth-hormone releasing-
`hormone
`
`Acromegaly
`
`?
`PP/F
`
`ACTH
`Pancreatic polypeptide (PP)
`
`Cushing's sy ndrome
`Hepatomegaly, abdominal pain
`
`Pancreas 90%
`
`Pancreas
`
`Pancreas 55%
`Duodenum 45%
`Pancreas 30%
`Lun g 50%
`jejunum 15%
`Pancreas 90%
`Pancreas 100%
`
`Percent malignant
`90
`
`10
`
`60
`
`90
`
`80
`
`60
`
`95
`80
`
`\.#
`N
`
`r.
`(i
`
`"" "' ::>
`e:: ;:;·
`2
`3
`0
`§
`
`Roxane Labs., Inc.
`Exhibit 1013
`Page 005
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`

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`GI Hormone Producing Tumours: Syndromes and Treatment Options
`
`33
`
`Well-differentiated tumours are positive for most markers of neuroendocrine
`differentiation in the vast majority of tumour cells. Poorly differentiated tumours
`do not express chromogranin A, but retain cytosolic markers together with synap(cid:173)
`tophysin. Other helpful features used to classify these tumours, and therefore to
`attempt to gauge their behaviour, include general morphologic description;
`mitotic rate (two or more mitoses per 10 high power [x400] microscopic fields);
`proliferative index (as assessed by nuclear Ki67 expression); tumour size; evidence
`· of invasion of blood vessels, nerves, or adjacent organs by the neoplasm; predom(cid:173)
`inant tumour synthesis of a specific hormone; or complete non-functionality of
`the tumour at an immunohistological level. Well-differentiated tumours are then
`named according to the specific endocrine cell of which they are composed
`(usually the cell types normally observed in the anatomical site of the tumour).
`Tumours falling into the two major categories of well-differentiated and poorly
`differentiated exhibit significant differences in phenotype and behaviour. The
`behaviour of well-differentiated tumours can be unpredictable, varying from
`benign to low-grade malignant; 1 according to the several clinicopathological
`parameters mentioned above, a tentative risk class is assigned to the tumour.
`Poorly differentiated (small cell) endocrine carcinomas are highly aggressive and
`are associated with a poor prognosis.
`
`MEN-1 Syndrome
`
`The MEN-I syndrome is most commonly associated with primary hyperparathy(cid:173)
`roidism, and tumours of the endocrine pancreas and anterior pituitary.
`This autosomal dominant inherited syndrome is associated with a germline
`genetic mutation in the MENl gene, on chromosome 11. 1 Genetic mapping studies
`show somatic loss of heterozygosity (LOH) suggesting that development of MENl
`associated tumours is a two-step process: firstly, a germline mutation affecting the
`first MENl allele; and then a somatic inactivation of the unaffected allele by
`LOH.u The MENI gene was cloned in 19973
`4 and encodes a 610 amino acid
`•
`protein called menin. Menin is a putative growth-suppressor protein, which
`specifically binds JunD, a transcription factor acting through the activator protein-
`1 (API complex). 5 API is a regulatory system within the cell, which is involved in a
`plethora of functions including apoptosis, mitosis and response to endogenous or
`exogenous growth factors.
`Characteristically, hyperparathyroidism is the initial manisfestation of MEN-I,
`usually presenting in the third decade of life, and followed by the development of
`an NPT between the ages of 35 and 50 years. Recognition of MEN-I is an impor(cid:173)
`tant first step in the management of NPTs, because patients with and without
`MEN-I differ in clinical presentation, clinical management approaches, and also
`prognosis. The presence of additional endocrinopathies may need specific
`management and may have an influence on the main tumour management. For
`example, in patients with gastrinoma and hyperparathyroidism, the presence of
`hypercalcaemia resulting from hyperparathyroidism often stimulates the release
`of gastrin from the tumour, and parathyroidectomy has to be performed before
`gastrinoma surgery. Patients with MEN-I may develop multiple tumours simulta(cid:173)
`neously, and more than one type of NPT over time, thus the chances of surgical
`cure and the approach to long-term follow-up will differ from patients without
`
`Roxane Labs., Inc.
`Exhibit 1013
`Page 006
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`

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`34
`
`Pancreatic Tumours
`
`MEN-I. Additionally, screening of other family members of MEN-I patients is
`indicated. Systematic biological screening performed on these patients includes:
`measurement of parathyroid hormone, serum calcium, prolactin, luteinising
`hormone, follicle stimulating hormone, growth hormone, adrenocorticotrophic
`hormone (ACTH), morning cortisol and 24 h urinary cortisol.
`Other hereditary neoplasia syndromes associated with NPTs include neuro(cid:173)
`fibromatosis type 1 and von Hippel-Lindau disease. Neurofibromatosis type 1 (NFl)
`is inherited in an autosomal dominant manner, arising from mutation of the NFl
`gene. The NFl gene is a tumor suppressor gene encoding a large protein
`(neurofibromin) that functions primarily as a RAS negative regulator.6 The hallmark
`feature of NF1 is the presence of neurofibromas arising either in the dermis or in
`peripheral nerve. However, patients also have an increased incidence of other
`tumours, including phaeochromocytomas and duodenal tumours, including somato(cid:173)
`statinomas. Clinically von Hippel-Lindau(VHL) disease displays an autosomal domi(cid:173)
`nant pattern of inheritance. Germline mutation of the VHL tumour suppressor gene
`on chromosome 3 causes a hereditary cancer syndrome characterised by the devel(cid:173)
`opment of retinal and central nervous system haemangioblastomas. Other tumours
`associated with VHL disease include clear cell renal carcinomas, phaechromocy(cid:173)
`tomas, and neuroendocrine tumours of the pancreas.7
`
`Clinical Syndromes of Neuroendocrine Tumours
`
`Gastrinomas
`
`Gastrinomas have an annual incidence of 0.5-1.5 per 106 persons,8 the majority of
`the tumours are located either in the pancreas or the duodenum. Less frequent
`sites are the small intestine and the stomach. 9 Approximately 20% of patients have
`a family history of neuroendocrine tumours, and 20-25% of patients (particularly
`those with duodenal tumours) have the MEN1 syndrome. MEN-1-associated
`gastrinomas usually present at an earlier age, and most MEN-1 patients have co(cid:173)
`existing hyperparathyroidism or pituitary disease at the time of presentation. As
`gastrin is trophic for the enterochromaffin cells in the fundus of the stomach (ECL
`cells), prolonged hypergastrinaemia may lead to the development of so-called
`ECLomas, which are also mostly benign neuroendocrine tumours. 10 ECLomas are
`more frequent in patients with MENl-associated gastrinoma (15-30%) than in
`those with sporadic gastrinoma ( <5%).
`Gastrinomas manifest with the characteristic Zollinger-Ellison syndrome
`(ZES), which is caused by hypergastrinaemia associated with hypersecretion of
`gastric acid. The most common symptom is abdominal pain caused by peptic
`ulcerationY Ulcers are most commonly found in the first part of the duodenum
`(approximately 75% ), and are usually single, but can be multiple. Ulcers are found
`much less often in the stomach, and in contrast to the common peptic ulcer, which
`is associated with Helicobacter pylori or ingestion of non-steroidal inflammatory
`drugs, may also by found in the second, third and fourth parts of the duodenum
`(14%), and in the jejunum (llo/o)Y Ulcers are often recurrent and/or resistant to
`medical or surgical treatment.
`Gastroesophageal reflux disease is also common. Approximately 60% of patients
`with Zollinger-Ellison Syndrome have dysphagia, or endoscopic evidence of
`erosive oesphagitis, including its complications of stricture formation, Barrett's
`
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`Exhibit 1013
`Page 007
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`Gl Hormone Producing Tumours: Syndromes and Treatment Options
`
`35
`
`14 A recently appreciated, important endoscopic sign
`epithelium, and perforation. 13
`•
`is the presence of prominent endoscopic folds, which was present in 94% of
`patients in a large prospective series of patientsY
`The other characteristic component of the syndrome is diarrhoea, which
`occurs in the majority of patients. 11 This is of the secretory or motor variety,
`and is always associated with hypersecretion of gastric acid, making it easily
`distinguishable from the diarrhoea associated with VIPomas, which is associated
`with hypochlorhydria. 15 The diarrhoea may accompany, precede or follow the
`peptic ulcer disease, or in some cases it may be the only manifestation. The large
`amounts of hydrochloric acid in the upper GI tract lowers the intraluminal pH,
`producing other effects: steatorrhoea, through the inactivation of pancreatic
`lipase, and the insolubilisation of some primary bile acids; vitamin B malabsorp(cid:173)
`tion, by interference with intrinsic factor-mediated vitamin B 12 absorption by the
`distal ileum. 12
`An estimated 60% of gastrinomas run a malignant course. Approximately 50%
`of patients with pancreatic or duodenal gastrinomas have lymph node and/or liver
`metastases at presentation. For many years, the main causes of death among gastri(cid:173)
`noma patients were the complications of peptic ulcer disease: perforation, haem(cid:173)
`orrhage and pyloric stenosis. However, with the advent of effective acid-reducing
`pharmacological agents, in particular proton pump inhibitors, the primary
`morbidity has changed to that of tumour growth and spread.
`
`lnsulinoma
`
`Insulinomas have an annual incidence of 1-2/106 persons/year, and usually
`occur in patients between 30 and 60 years of age. lnsulinomas are small (81%
`measure 20 mm or less), 16 usually solitary, and are almost always confined to the
`pancreas. They are evenly distributed within the head, body and tail of the
`pancreas. Approximately 10% of the tumours are malignant tumours, these are
`usually larger than benign lesions, and can lead to widespread metastases.
`Multiple tumours occur in up to 10% of patients and should raise the possibili(cid:173)
`ty of MEN-I syndrome.
`The tumour is characterised by hypersecretion of insulin and hypoglycaemia.
`Symptoms occur as the result of hypo glycaemia and characteristically occur when
`a meal is delayed or missed, with fasting, or during exercise.17 Most patients
`present with neurological symptoms of hypoglycaemia, such as visual disturb(cid:173)
`ances, altered mood/confusion, weakness, transient motor defects, fatigue, dizzi(cid:173)
`ness, and even coma. Hypoglycaemia can also cause symptoms of adrenergic
`hyperactivation, such as hunger, palpitations, sweating and tremor. When the diag(cid:173)
`nosis is made late, hypoglycaemia may even cause permanent cerebral damage.
`The symptoms can be partially masked by a tendency to over-eat in order to
`compensate for the hypoglycaemia. For this reason, insulinoma patients are often
`overweight. 18
`
`VIPoma
`
`Vasoactive intestinal polypeptide (VIP)-secreting tumours (VIPomas) account for
`less than 10% of pancreatic neuroendocrine tumours. They are much more
`
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`Exhibit 1013
`Page 008
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`

`
`36
`
`Pancreatic Tumours
`
`common in women (with a female:male ratio of 3:1), and most frequently occur at
`around the fourth decade of life.9 Up to 90% of VIPomas originate from the
`pancreas, and are usually solitary tumours. The remaining 10% are tumours of the
`nervous system, such as ganglioneuromas, neuroblastomas and phaeochromocy(cid:173)
`tomas. Approximately 5% of VIPomas are MEN-1-associated. Over 60% of
`pancreatic VIPomas are malignant, and by the time of diagnosis up to 60% have
`metastasized to lymph nodes, liver, kidneys, or bone.8
`19
`•
`The hypersecretion of VIP produces a syndrome characterised by severe secre(cid:173)
`tory diarrhoea, associated with hypokalaemia and dehydration, and is commonly
`called the Verner-Morrison Syndrome. The diarrhoea is intermittent in 53% of
`patients, and continuous in 47%. The volume of diarrhoea is large, with the major(cid:173)
`ity of patients having more than 3 l!day.20 The pathogenesis of the severe
`hypokalaemia is probably primarily caused by faecal loss, and if left uncorrected
`may be severe enough to cause life-threatening cardiac arrthymias. Other elec(cid:173)
`trolyte abnormalities include: hypochlorhydria, hypercalcaemia, hyperglycaemia,
`and hypomagnesaemia. 17 A less frequent symptom is cutaneous flushing, which is
`characteristically erythematous, and occurs in 20% of patients.
`
`Glucagonomas
`
`Glucagonomas are less than half as common as VIPomas, with an annual incidence
`of 0.01-0.1 new cases per million. They are slightly more common in women
`(55%), and usually occur after 45 years of age.21 Most glucogonomas are large soli(cid:173)
`tary tumours, which are almost exclusively found in the pancreas. They generally
`exhibit highly malignant behaviour: approximately 90% of patients already have
`lymph node and/or liver metastases at presentation. 8 Glucagonoma is rarely asso(cid:173)
`ciated with MEN -1.
`Glucagonomas secrete excessive amounts of glucagon and cause a distinct
`syndrome that is characterized by a specific dermatitis (necrolytic migratory
`erythema), weight loss, diabetes mellitus, and anaemia. The cutaneous lesions are
`one of the most common manifestations of the disease, being present in about 90%
`of patients. Characteristically, the skin lesion starts as an erythematous area that
`subsequently becomes papular, with superficial blistering that frequently erodes
`and crusts. Healing is associated with hyperpigmentation of the area involved. The
`eruption is usually localized to the buttocks, groin, perineum, elbows, hands, feet
`and perioral area. The glucagon-induced hypoaminoacidaemia that develops in
`the majority of patients is implicated in the pathogenesis of the rash.
`Glucose intolerance, with or without frank diabetes mellitus, develops in 85%,
`principally due to the hyperglycaemia that results from glucagon-stimulated
`hepatic glycogenolysis and gluconeogenesis. Weight loss is almost universal, and
`probably reflects the known catabolic actions of glucagon. Weight loss may be as
`severe as 20-30kg, and may occur even with small non-metastatic tumours.
`Normochromic, normocytic anaemia develops in 60% of patients, and is probably
`caused by an inhibitory effect of prolonged hyperglucagonaemia on erythro(cid:173)
`poiesis.22 Other abnormal laboratory findings commonly found include hypoalbu(cid:173)
`minaemia (in 80% of patients), and hypocholesterolaemia (reduced VLDL in 80%
`of patients), which both reflect reduced hepatic synthesis.
`Less common symptoms include; deep venous thrombosis (20%), pulmonary
`emboli (10%), diarrhoea (15%), and psychiatric disturbance.
`
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`Exhibit 1013
`Page 009
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`Gl Hormone Producing Tumours: Syndromes and Treatment Options
`
`37
`
`Somatostatinoma
`
`Somatostatinomas are usually solitary tumours, which originate in the pancreas
`or small intestine. They are rare tumours, and account for less than S% of
`pancreatic neuroendocrine tumours. Somatostatinomas of the pancreas and
`small intestine differ in several respects: a clinical syndrome is encountered
`more frequently (18.S% versus 2.So/o ), the large size of the tumour
`(>20 mm)(SS.S% versus 41.4%), the association with neurofibromatosis type 1
`(von Recklinghausen's disease)(l.2% versus 43.2%), and the presence of psam(cid:173)
`moma bodies (2.So/o versus 49.4%) .23 The majority of somatostatinomas are
`overtly malignant at presentation, and have evidence of metastatic spread to the
`liver and/or lymph nodes. 24
`Somatostatinomas release large amounts of somatostatin and cause a distinct
`clinical syndrome characterized by diabetes mellitus, gallbladder disease, and
`diarrhoea with steatorrhoea. Approximately 40% of patients with somatostatin(cid:173)
`omas remain asymptomatic, and the tumour is discovered incidentally.
`The development of diabetes mellitus, which is usually mild, is likely to be
`secondary to the inhibitory action of somatostatin on insulin, glucagon and
`growth hormone release, as well as the replacement of functional pancreatic
`tissue. Gallbladder disease may be a result of somatostatin inhibition of gall(cid:173)
`bladder emptying. Diarrhoea and steatorrhoea probably reflect inhibition by
`somatostatin of pancreatic secretion of enzymes and bicarbonate, gallbladder
`motility, and intestinal absorption of lipidsY All of these symptoms may also
`occur in patients treated with somatostatin analogues, such as octreotide. Other
`symptoms include weight loss, which may be secondary to malabsorption,
`and hypochlohydria, which is probably secondary to inhibition of gastric acid
`secretion. 17
`
`GRFomas
`
`GRFomas are defined as extracranial tumours that are predominantly or exclu(cid:173)
`sively composed of cells that synthesize and release growth hormone-releasing
`factor (GRF) (also known as GHRH), which leads to growth hormone (GH) hyper(cid:173)
`secretion and acromegaly. The average age of GRFoma patients at presentation is
`40years, and at variance with pituitary adenoma, GRFoma is 3 times more
`common in women than in men. Differentiation of GRF-driven acromegaly from
`GH hypersecretion from a pituitary adenoma can be difficult. Radiological
`imaging of the sella turcica is often unhelpful, since 40-4S% of patients with
`GRFomas show a hypophyseal mass resembling an adenoma, usually due to hyper(cid:173)
`plasia of somatotrophs. Detection of an extrahypophyseal tumour, together with
`an elevated plasma GRF level, is the most useful aid to diagnosis.
`GRFomas have been reported in the pancreas (30% of cases), bronchus (SO% of
`cases, where they can be associated with bronchial carcinoid tumours), and in the
`jejunum (IS% of cases). Approximately 30% of tumours are overtly malignant at
`the time of diagnosis. About 40% of patients with GRFomas have other associated
`secretory syndromes, especially through the expression of the MEN-1 syndrome.
`Co-existing endocrinopathies include hyperparathyroidism, Zollinger-Elision
`syndrome, hypoglycaemia, Cushing's syndrome and phaeochromocytoma.24
`
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`Exhibit 1013
`Page 010
`
`

`
`38
`
`ACTHomas
`
`Pancreatic Tumours
`
`These tumours are very rare, and are usually located in the pancreas (90% of
`cases). They produce ACTH and ectopic Cushing's syndrome. The tumours often
`co-secrete, and so the syndrome is often associated with another syndrome.
`Approximately 95% have metastasised at the time of diagnosis.
`
`NPTs Causing Carcinoid Syndrome
`
`Tumours secreting 5-hydroxytryptamine (5HT) or pancreatic 'carcinoids' account
`for 1-2 o/o of NPTs. These tumours also produce other peptides such as histamine,
`kinins, substance P and prostaglandins. Unless these secretory peptides are
`released directly from metastases into the systemic circulation (intestinal drainage
`is into the portal system), they do not usually cause any signs or symptoms.
`Paracrine secretion in the intestine may however cause diarrhoea. Therefore,
`systemic features of the carcinoid syndrome only usually become apparent when
`liver metastases are present. This syndrome is characterised by flushing and diar(cid:173)
`rhoea, and less commonly by wheezing, abdominal pain and heart disease.
`Pancreatic carcinoids with excess production of histamine may cause an atypical
`carcinoid syndrome (generalised flushing, lacrimation, hypotension, cutaneous
`oedema, bronchoconstriction). Approximately 10% of carcinoid tumours are asso(cid:173)
`ciated with MEN1. 25
`
`NPTs Causing Hypercalcaemia
`
`Hypercalcaemia has been reported with NPTs secreting parathyroid hormone(cid:173)
`related protein that mimics the actions of parathyroid hormone. The tumours are
`usually large and have metastased to the liver by the time of diagnosis. 17
`26
`•
`
`Nonfunctioning Tumours
`
`is
`tumours
`incidence of non-functioning pancreatic endocrine
`The
`1-2/106 persons/year, and these tumours represent about 60% of the total
`number of pancreatic neuroendocrine tumours. By definition, nonfunctioning
`endocrine tumours of the pancreas are those that have all the histological char(cid:173)
`acteristics of a pancreatic neuroendocrine tumour, but no associated clinical
`syndrome related to hormone hypersecretion. These tumours are often produc(cid:173)
`ing hormones, but remain clinically 'silent' for a number of reasons. The
`peptides or hormones produced may not produce a known specific clinical
`syndrome, for example, pancreatic polypeptide (PPomas), a- and f)-human
`chorionic gonadotrophin, calcitonin, and chromogranin A. In other cases, the
`tumour may produce a peptide which is well known to produce a clinical
`syndrome, but fails to release it, or produces it at only very low plasma concen(cid:173)
`trations. It may also be that the tumour only produces biologically inactive
`precursor forms of the peptide, or that it simultaneously produces an inhibitory
`peptide, such as somatostatinY
`
`Roxane Labs., Inc.
`Exhibit 1013
`Page 011
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`

`
`GJ Hormone Producing Tumours: Syndromes and Treatment Options
`
`39
`
`The tumours are usually unifocal, and are predominantly situated in the head of
`the pancreas. Between 20 and 40% of non-functioning pancreatic neuroendocrine
`tumours are MEN-1-associated, and in this situation may be multifocal. Patients
`present with symptoms related to expanding tumour mass, most commonly jaundice
`and epigastric pain, but also with weight loss, steatorrhoea, upper gastrointestinal
`bleeding, recurrent pancreatitis, fatigue and malaise. An increasing number are being
`30
`detected incidentally. Reported malignancy rates at presentation are 60-90%.29
`•
`It should be noted that a tumour which has presented as a non-functioning
`tumour, can later turn into a functioning tumour, for example a gastrinoma. 27
`
`Diagnosis
`
`Pancreatic neuroendocrine tumours produce specific symptoms and hormones.
`The diagnosis is therefore based on clinical symptoms, hormone measurement,
`radiological and nuclear medicine imaging and histological confirmation. The
`gold standard is histology and should be obtained wherever possible. The
`minimum diagnostic criteria for the various syndromes includes histology and
`the following tests:
`
`Fasting Gut Hormones
`
`lnsulinoma
`
`The demonstration of inappropriately high insulin levels in the presence of hypo(cid:173)
`glycaemia after prolonged fasting is used to diagnose insulin-producing tumours.
`Hypoglycaemia is usually defined as a blood glucose below 2.2 mmol/1 ( 40 mg/dl).
`Within 24 h of fasting, most patients develop hypoglycaemia, and by 72 h, virtual(cid:173)
`ly all patients will be hypoglycaemic. Paired samples of insulin and glucose are
`taken every 3-4 h. The test is terminated, and intravenous glucose is administered,
`when the serum glucose drops to 2.2 mmol/1 or below, and/or the patient becomes
`symptomatic. The test is considered positive for insulinoma if the ratio of plasma
`insulin (in f..LU/ml) to glucose (in mg/dl) is more than 0.3. A value of 20 pmol!mmol
`(insulin concentration [pmol/1] divided by glucose concentration [mmol/1]) can
`also be used to differentiate patients with and without insulinoma.31
`Caution must be taken to exclude factitious hypoglycaemia, which may be partic(cid:173)
`ularly prevalent amongst medical workers or in relatives of diabetic patients. This can
`be done by measurement of C-peptide (endogenous flanking peptide of insulin) and
`pro-insulin (which is elevated in up to 90% of patients with insulinoma). Levels of
`these peptides will be normal or low following administration of insulin. In the case
`of deliberate or accidental use of sulphonyureas, elevated levels of insulin and
`C-peptide are found, but proinsulin levels are normal or low. In this case, serum can
`be screened for the presence of hypoglycaemics. 18
`
`Gastrinoma
`
`The most important diagnostic test for gastrinoma is an elevated fasting serum
`gastrin in the presence of gastric acid secretion after discontinuation of acid
`reducing medications (ie. H2 receptor antagonists and proton pump inhibitors).
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`Exhibit 1013
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`40
`
`Pancreatic Tumours
`
`A level of greater than 1000 pmol!ml, is virtually diagnostic of ZES. However,
`hypergastrinaemia can also be present in a number of other conditions, including
`Helicobacter pylori infection, and gastric outlet obstruction. Many patients with
`ZES will have only a modest elevation of fasting serum gastrin (between 100 and
`1000pmol!l), and in these patients a secretin stimulation test may be of some
`help. 25 Secretin is a potent stimulator of gastrin release from gastrinomas, but has
`little effect on other types of gastrinaemia.
`
`Other Hormones
`
`The diagnosis of glucagonoma syndrome can be made easily by measurement of
`fasting plasma glucagon. In the vast majority of patients with the syndrome, basal
`levels of glucagon exceed the normal range by six-fold. 21
`The Verner-Morrison syndrome can be diagnosed by demonstration of an
`elevated fasting plasma VIP level. The usual increase in plasma VIP is 50-fold
`above the normal mean concentration. A raised plasma pancreatic polypeptide
`level is frequently also seen in pancreatic VIPomas. 32
`
`Somatostatinoma
`
`Plasma somatostatin levels are usually elevated in pancreatic somatostatinomas.
`Levels may however be inconclusive or normal in duodenal or small intestinal
`tumours. 17
`
`GRFoma
`
`Plasma GRF (GHRH) levels are usually elevated in patients with GRFoma, and are
`normal in patients with pituitary acromegaly. Growth hormone (GH) and insulin(cid:173)
`like growth factor-1 (IGF-1) are invariably elevated, and GH levels fail to suppress
`after an oral glucose load in all forms of acromegaly. 33
`
`A aHoma
`
`These patients usually have an elevated plasma ACTH and high cortisol levels. This
`does not however differentiate an extra-pituitary ACTH-producing tumour from
`pituitary-dependent Cushing's disease, with which it may share some clinical
`features. Factors favouring the diagnosis of an extra-pituitary ACTH-secreting
`tumour include, the presence of hypokalaemia with metabolic acidosis, the co(cid:173)
`secretion of other gut hormones, male sex, and advanced age. 34
`
`Chromogranin A
`
`The chromogranins are a unique family of water-soluble acidic glycoproteins
`found in the storage vesicles of neuroendocrine cells and released during
`
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`Exhibit 1013
`Page 013
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`

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`GJ Hormone Producing Tumours: Syndromes and Treatment Options
`
`41
`
`exocytosis. Chromogranin A ( CgA) was the first discovered chromo gran in and is
`found throughout the diffuse neuro/endocrine system. It is an excellent immuno(cid:173)
`histochemical marker of neuroendocrine differentiation, and because it is co(cid:173)
`released with resident peptide hormones/amines contained within the secretory
`granules, it can also serve as a serum marker of neuroendocrine activity. The
`serum concentration of CgA is elevated in patients with various neuroendocrine
`tumours. Nonfunctioning neuroendocrine tumours, for which no peptide marker
`is available, usually retain the ability to secrete CgA. CgA can therefore be used as
`a tumou