Published online 16 July 2009
Haematologica, Vol 94, Issue 12, 1758-1761 doi:10.3324/haematol.2009.010496
Copyright © 2009 by Ferrata Storti Foundation
Pancreatic enzyme elevation in chronic myeloid leukemia patients treated with nilotinib after imatinib failure
Francesca Palandri,
Fausto Castagnetti,
Simona Soverini,
Angela Poerio,
Gabriele Gugliotta,
Simona Luatti,
Marilina Amabile,
Giovanni Martinelli,
Gianantonio Rosti,
Michele Baccarani
Department of Hematology and Oncology "L. and A. Seràgnoli", St. Orsola-Malpighi Hospital, University of Bologna, Italy
Correspondence: Francesca Palandri, MD, Department of Hematology and Medical Oncology "L. and A. Seràgnoli", St. Orsola-Malpighi University Hospital, Via Massarenti, 9, 40138 Bologna, Italy. E-mail: francesca.palandri{at}libero.it

ABSTRACT
An increase in the serum concentration of pancreatic enzymes
(amylase and lipase) was reported in a proportion of imatinib-resistant
and/or intolerant Philadelphia-positive chronic myeloid leukemia
patients treated with nilotinib. Acute pancreatitis was very
rare, and the relevance of these laboratory alterations remains
unknown. We report on 8 chronic myeloid leukemia patients who
developed serum lipase/amylase elevation during treatment with
nilotinib. After a median follow-up of 26 months, none of these
patients developed an acute pancreatitis or clinical signs of
pancreatic disease. Pancreatic hyperenzymemia never led to permanent
drug discontinuation and required nilotinib temporary interruption
in one case only. The median cumulative duration of dose interruptions
and response to treatment were comparable in patients with or
without pancreatic enzyme elevation. The mechanisms of action
of nilotinib on pancreatic enzymes deserves to be investigated:
however, in our experience, the relevance of pancreatic hyperenzymemia
was clinically very limited.
Key words: hyperlipasemia, hyperamylasemia, pancreatic enzymes, chronic myeloid leukemia, imatinib, nilotinib.

Introduction
Thanks to its striking effectiveness, imatinib (IM) (Glivec,
Gleevec; Novartis Pharmaceuticals, NJ), a Bcr-Abl tyrosine kinase
inhibitor (TKI), has rapidly become the standard front-line
treatment of Philadelphia positive (Ph-pos) chronic myeloid
leukemia (CML).
1,2 However, about 5% of the patients must discontinue
imatinib due to adverse events (AEs) and about 20% of the patients
fail to respond adequately, according to the European LeukemiaNet
criteria.
3 In CML patients resistant or intolerant to imatinib,
alternative treatments are needed. Nilotinib (Tasigna®,
formerly AMN107; Novartis Pharmaceuticals, NJ) is an oral aminophenylpyrimidine
derivative that has been rationally designed to be more selective
against the Bcr-Abl tyrosine kinase than imatinib. The higher
selectivity results in a superior potency against imatinib-resistant
cell lines, including most of the cell lines which bear mutations,
and also in a lower incidence of adverse events.
4,5 Nilotinib
has proved to be effective and safe in large studies involving
patients with imatinib-resistant and/or intolerant CML; however,
a significant (up to 18%) incidence of grade 3–4 pancreatic
enzyme elevation has been reported.
6–8 Enzyme increase
was not associated to acute pancreatitis in the great majority
of cases; nonetheless, no data have yet been reported which
describe the behavior of pancreatic enzymes over time and the
clinical relevance of these laboratory alterations. For this
purpose, we report our experience with 37 imatinib-resistant
or intolerant CML patients who were treated with nilotinib.

Design and Methods
Patients were enrolled between June 2005 and February 2008 in
two studies sponsored by Novartis Pharmaceuticals (registered
at
www.clinicaltrials.gov under NCT00384228 and NCT00302016).
The studies were conducted in accordance with the Declaration
of Helsinki. Both studies were approved by the ethics committee
of the St. Orsola-Malpighi University Hospital and all patients
gave written informed consent according to institutional guidelines.
Enrolment criteria have been described elsewhere.
6 Briefly,
patients with imatinib-resistant or intolerant CML in chronic
phase, accelerated phase and blast crisis who were at least
18 years old were eligible if they had adequate performance
status (World Health Organization Performance Score

2), and
normal hepatic, renal, and cardiac functions. Nilotinib starting
dose was 400 mg twice daily for all patients. Blood counts and
biochemistries were obtained weekly for the first eight weeks,
and thereafter every two weeks. Cytogenetic studies on bone
marrow samples were performed with conventional cytogenetic
analysis at baseline and at 3–6 month intervals thereafter.
The cytogenetic response was rated according to European LeukemiaNet
guidelines.
3 Safety assessments included: evaluation of adverse
events, hematologic and biochemical testing, urinanalysis, cardiac
enzyme assessment, serial electrocardiogram evaluation, and
physical examination. Amylase and lipase concentrations were
measured at the central laboratory of our hospital. The normal
reference range is 20–110 IU/L for amylase and 13–55
IU/L for lipase. Adverse events were graded according to the
National Cancer Institute Common Terminology Criteria for Adverse
Events Version 3.0.

Results
Patients
A total of 37 CML patients intolerant or resistant to imatinib
were enrolled in the studies. Nineteen were male and 18 female.
Median age at CML diagnosis was 49 years (range, 12–71);
median interval between CML diagnosis and nilotinib start was
48 months (range, 4–266). Twenty-four patients were in
chronic phase, 4 in accelerated phase and 9 in blast phase (4
lymphoid and 5 myeloid blast phase). Nilotinib was initiated
because of imatinib-resistance in 30 patients (81%). In the
remaining 7 imatinib-intolerant patients, reasons for imatinib
discontinuation were: fluid retention (4 patients), skin reactions
(1), hematologic toxicity (2). Median follow-up of living patients
was 29 months (range, 9–42).
Incidence and severity of pancreatic enzyme elevations
Lipase and amylase serum levels have been performed in all patients every 1–3 months, according to protocol requirements and to medical indications, during the entire course of nilotinib therapy. Fasting serum glucose levels were normal and no signs of malabsorption were ever recorded. Therefore, pancreatic function tests were neither required nor performed. During the course of nilotinib therapy, 8 patients (21.6%) showed increased lipase and/or amylase levels (Table 1). Seven patients were in chronic phase and one in accelerated phase. Median age at nilotinib start was 51 years (range, 36–68); 6 were male and 2 female. The median interval between nilotinib start and lipase/amylase elevation was three months (range, 7 days–30 months). Lipase elevation was detected as single alteration in 5 patients, while a transient amylase elevation was concomitantly detected in 2 patients. One patient experienced isolated serum amylase elevation grade 2. Overall, in 5 cases (13.5%) serum lipase increase was grade 3 (from 2 to 5 times over the upper normal limit), whereas all amylase elevations were grade 2 (from 1.5 to 2 times over the upper normal limit). Pancreatic enzyme increase presented as single isolated elevated values or as transient episodes in all cases, with the exception of patient MB, who experienced frequent recurrences of hyperenzymemia. During treatment, all patients had maintained the same lifestyle and alimentary habits; in particular, alcohol abuse was excluded in all cases. Concomitant drugs were also recorded (Table 1), but none of them seemed to be related to pancreatic hyperenzymemia.
Clinical implications of pancreatic enzyme elevations
In all these subjects, the hyperenzymemia was discovered incidentally
when tests for pancreatic enzymes were carried out as a part
of a routine work-up. None of these patients was diabetic, nor
presented a history positive for gastrointestinal diseases,
including gallstones, bile duct occlusions, pancreatitis, hepatitis.
At the first evidence of enzyme elevation, all patients were
studied with abdominal ultrasonography, which resulted normal
in all cases. Other concomitant AEs were recorded and are listed
in
Table 1. Impaired renal function was also excluded. None
of the patients developed acute pancreatitis. Patient MB presented
a serum lipase increase grade 3 at baseline evaluation; an abdominal
computed tomography (CT) excluded pancreatic pathoanatomic anomalies
before nilotinib start. In this patient, pancreatic enzymes
showed a fluctuating behavior; the phenomenon was monitored
with 15-day clinical and laboratory tests, and was investigated
with 3 computed tomography scans and one MRCP (magnetic resonance
colangio-pancreatography), all of which failed to reveal abdominal
anatomic alterations. Endoscopic retrograde pancreatography
9 and exocrine pancreatic function study by the secretin-cerulein
test
10 were not performed because potentially hurtful, in absence
of clinical signs of pancreatic disease. At last follow-up,
42 months after nilotinib start, the patient is alive and well,
in continuous, nilotinib-induced complete cytogenetic response,
and in ongoing therapy with nilotinib at reduced dosage (400
mg daily) (
Figure 1).
Overall, nilotinib dose was reduced to 400 mg daily in 4 patients,
because of pancreatic hyperenzymemia (patients MB and MG), recurrent
thrombocytopenia (patient PG) and gastric intolerance (patient
PD). Only patient MG discontinued nilotinib for 26 days because
of hyperenzymemia; the median cumulative duration in days of
dose interruption was similar in CP-CML patients with or without
pancreatic enzyme elevations (19 days, range 0–50,
vs. one day, range 0–146, respectively,
p=0.23). The proportion
of complete cytogenetic responders was also comparable in the
two groups: among the 7 CP-CML patients with pancreatic hyperenzymemia,
6 achieved a complete cytogenetic response (versus 9 complete
responders out of 17 chronic phase patients without enzyme elevation,
p=0.19).

Discussion and Results
Pancreatic enzyme elevation was reported as an unexpected adverse
event in CML patients treated with nilotinib after imatinib
failure. Among the 119 CML patients treated with nilotinib in
accelerated phase, 18% and 2% of the patients experienced a
grade 3–4 increase in lipase and amylase levels, respectively,
with one patient developing acute pancreatitis after a median
duration of treatment of 6.7 months.
7 Grade 3–4 elevation
of serum lipase levels was also recorded in 14% of 318 CML patients
treated with nilotinib in chronic phase, and acute pancreatitis
was reported in 3 cases (1%), with a median duration of exposure
of eight months.
6,8
The reason for pancreatic enzyme elevation is unknown. One mechanism may be due to the capability of nilotinib to inhibit with high affinity the non-receptor tyrosine kinase c-Abl. Besides the kinase domain, the c-Abl protein interacts with signaling proteins, nucleo-cytoplasmic shuttling, DNA and actin binding sites, thus integrating information from multiple pathways in different cellular compartments.11 Therefore, it is possible that c-Abl inhibition might interfere with the molecular mechanisms regulating pancreatic cell death, inducing pancreatic damage. Another possibility is that the drug may act on unknown intracellular pathways involved in calcium release from the intracellular acinar stores, which regulate exocrine pancreatic secretion,12,13 or may promote the accumulation of fatty acid inside the pancreatic acinar cell, which disturbs exocytosis.14 However, pancreatic enzyme elevations are rarely observed during exposure to other ABL kinase inhibitors, and the molecular mechanisms of action of nilotinib on pancreatic enzyme level deserves to be investigated. Defining and controlling the clinical implications of the side effects of a new oncology drug is particularly important and challenging, considering the gravity of the disease and the potential therapeutic effect. An increase in serum concentration of pancreatic enzyme is usually an expression of pancreatic disease;15 however, several conditions can be responsible for elevated amylase and/or lipase levels, which may also be a non-specific phenomenon without any clinical implication.16,17 Particularly, benign pancreatic hyperenzymemia (BPH)18 is a syndrome characterized by pancreatic enzyme elevations persisting over time with considerable fluctuations, in the absence of pancreatic disease, a condition very similar to that observed in patient MB (Figure 1).
Regular monitoring and prolonged observation are needed to establish whether pancreatic enzyme elevations during nilotinib therapy are a benign laboratory abnormality or a serious adverse event reflecting a (potential) pancreatic disease. In our experience, with a median observation time longer than two years, these alterations were short-lasting and self-limiting, requiring preventative temporary drug discontinuation in one patient only. None of the patients required permanent treatment interruption due to pancreatic enzyme elevation and nilotinib dose was precautionarily reduced in 2 cases only. More importantly, no patient developed acute pancreatitis or clinical signs of pancreatic disease, such as pancreatic-type pain, obstructive jaundice, maldigestion, diabetes, pancreatic cysts and ascites.

Acknowledgments
the skilful assistance of Irina Mantovani is gratefully acknowledged.

Footnotes
Funding: the study was supported by European LeukemiaNet funds,
the Italian Association for Cancer Research (A.I.R.C.), COFIN,
and BolognAIL.
Authorship and Disclosures
GR, GM, MB: conception and design; FC, GG, SS, AP, SL, MA, GM; provision of study materials or patients; FP: collection and assembly of data; FP, GR, MB: data analysis and interpretation; FP, GR, MB: manuscript writing; MB: final approval of manuscript.
GM and GR received consultation fees on honoraria from Novartis Pharma and Bristol-Myers Squibb. MB received consultation fees on honoraria from Novartis Pharma.
Received for publication April 24, 2009.
Revision received June 1, 2009.
Accepted for publication June 15, 2009.

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