Clozapine Induced Weight Gain

Clozapine Induced Weight Gain: A Pharmacogenetic Study

Clozapine is prescribed to patients with psychosis in whom other treatments have not worked. Research has shown, however, that clozapine may be associated with weight gain and abnormal blood sugar levels in some patients. There is strong evidence to suggest that genetic variation between individuals plays an important role in the development of these side effects in response to the medication. Our research aims to evaluate the effects of two genes and the blood level of clozapine on side-effects such as weight changes and blood sugar levels in patients receiving clozapine treatment. From out-patient clinics in Cwm Taf UHB, the investigators aim to recruit 160 patients who are taking clozapine; collect information/ measurements from recruits relating to size/ weight/ BMI, risk of diabetes and blood samples to measure markers of blood sugar, fat/lipids, clozapine and its breakdown products, blood cells and variants of two specific genes. From this information the investigators will be particularly interested to understand if there is any association between the variation in these two genes with weight gain or changes in blood sugar, in patients taking clozapine.

Study Overview

• Status: Unknown
• Conditions: Weight Gain; Pharmacogenetics; Antipsychotic Agents
• Intervention / Treatment: Other: No study intervention - observational study

• Study Type: Observational
• Enrollment (Anticipated): 160

Contacts and Locations

• Study Contact: Name: Brian P Tennant, PhD; Phone Number: (+44)1685728278; Email: brian.tennant@wales.nhs.uk
• Study Contact Backup: Name: Rhian Beynon, MSc; Phone Number: 01443444500; Email: rhian.beynon@wales.nhs.uk

Study Locations

• United Kingdom
  • Wales
    • Merthyr Tydfil, Wales, United Kingdom, CF47 9DT
      • Cwm Taf University Health Board
      • Contact: Rhian Beynon, MSc; Phone Number: 01443444500; Email: rhian.beynon@wales.nhs.uk
      • Contact: Brian P Tennant, PhD; Phone Number: (44)1685728278; Email: brian.tennant@wales.nhs.uk

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 16 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

• Sampling Method: Probability Sample

Study Population

Patients on clozapine treatment

Description

Inclusion Criteria:

• Age 18 years or over
• Taking/compliant with clozapine antipsychotic medications.
• Patients meeting the ICD-10 criteria for a diagnosis of schizophrenia, schizoaffective or borderline personality disorders.

Exclusion Criteria:

• History of current alcohol/illicit substance dependency.
• Unable/ unsuitable to complete the study protocol e.g. acutely ill, suicidal or aggressive patients.
• Unable to consent to the study.

Study Plan

How is the study designed?

Design Details

• Observational Models: Cohort
• Time Perspectives: Prospective

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Body-mass index (BMI)	BMI will be calculated by weight (kg)/ height^2 (m^2).	12 months
Leptin gene promoter region single nucleotide polymorphisms (SNPs) (rs7799039)	SNPs will be determined by polymerase chain reaction followed by restriction fragment length polymorphism analysis to determine (c.-2548G or c.-2548A) .	12 months
Serotonin 5-HT 2C receptor gene single nucleotide polymorphisms (SNPs) (rs3813929)	SNPs will be determined by polymerase chain reaction followed by restriction fragment length polymorphism analysis to determine (c.-759C or c.-759T) .	12 months

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Blood haemoglobin A1c concentration	Haemoglobin A1c concentrations will be determined by ion-exchange HPLC (G8, Tosoh, Amsterdam, Netherlands)	6 months
Waist:hip ratio	Waist:hip ratio will be calculated by waist circumference (cm)/hips circumference (cm)	12 months
Lipid profile	Serum lipid profiles will include total cholesterol, HDL cholesterol, LDL cholesterol and triglyceride. These will be measured by enzymatic colorimetric methods on cobas-Roche analysers (Roche, Burges Hill, UK) except LDL cholesterol, which will be calculated using the Friedewald equation ([LDL cholesterol] = [Total cholesterol] - ([Triglyceride] / 2.2) - [HDL cholesterol]	12 months
Clozapine side effects assessment by Clinical Global Impression (CGI) scale	Clinical Global Impression (CGI) scale is a validated tool to assess clozapine side effects (Ref: Guy W, editor. ECDEU Assessment Manual for Psychopharmacology. 1976. Rockville,MD, U.S. Department of Health, Education, and Welfare)	12 months
Clozapine:nor clozapine ratio	Clozapine:nor clozapine ratio is calculated by clozapine (ug/L)/ nor clozapine (ug/L) both measured by high-performance liquid chromatography with diode-array detection.	12 months

Collaborators and Investigators

• Sponsor: Cwm Taf University Health Board (NHS)
• Investigators: Principal Investigator: Brian P Tennant, PhD, Cwm Taf Morgannwg UHB

Publications and helpful links

General Publications

• Allison DB, Mentore JL, Heo M, Chandler LP, Cappelleri JC, Infante MC, Weiden PJ. Antipsychotic-induced weight gain: a comprehensive research synthesis. Am J Psychiatry. 1999 Nov;156(11):1686-96. doi: 10.1176/ajp.156.11.1686.
• Baptista T, Kin NM, Beaulieu S, de Baptista EA. Obesity and related metabolic abnormalities during antipsychotic drug administration: mechanisms, management and research perspectives. Pharmacopsychiatry. 2002 Nov;35(6):205-19. doi: 10.1055/s-2002-36391.
• Basile VS, Masellis M, McIntyre RS, Meltzer HY, Lieberman JA, Kennedy JL. Genetic dissection of atypical antipsychotic-induced weight gain: novel preliminary data on the pharmacogenetic puzzle. J Clin Psychiatry. 2001;62 Suppl 23:45-66.
• Couchman L, Morgan PE, Spencer EP, Flanagan RJ. Plasma clozapine, norclozapine, and the clozapine:norclozapine ratio in relation to prescribed dose and other factors: data from a therapeutic drug monitoring service, 1993-2007. Ther Drug Monit. 2010 Aug;32(4):438-47. doi: 10.1097/FTD.0b013e3181dad1fb.
• Mammes O, Betoulle D, Aubert R, Herbeth B, Siest G, Fumeron F. Association of the G-2548A polymorphism in the 5' region of the LEP gene with overweight. Ann Hum Genet. 2000 Sep;64(Pt 5):391-4. doi: 10.1017/s0003480000008277.
• Mantzoros CS. The role of leptin in human obesity and disease: a review of current evidence. Ann Intern Med. 1999 Apr 20;130(8):671-80. doi: 10.7326/0003-4819-130-8-199904200-00014.
• Ohlson LO, Larsson B, Svardsudd K, Welin L, Eriksson H, Wilhelmsen L, Bjorntorp P, Tibblin G. The influence of body fat distribution on the incidence of diabetes mellitus. 13.5 years of follow-up of the participants in the study of men born in 1913. Diabetes. 1985 Oct;34(10):1055-8. doi: 10.2337/diab.34.10.1055.
• Reynolds GP, Zhang ZJ, Zhang XB. Association of antipsychotic drug-induced weight gain with a 5-HT2C receptor gene polymorphism. Lancet. 2002 Jun 15;359(9323):2086-7. doi: 10.1016/S0140-6736(02)08913-4.
• Reynolds GP, Zhang Z, Zhang X. Polymorphism of the promoter region of the serotonin 5-HT(2C) receptor gene and clozapine-induced weight gain. Am J Psychiatry. 2003 Apr;160(4):677-9. doi: 10.1176/appi.ajp.160.4.677.

Study record dates

Study Major Dates

• Study Start (Anticipated): March 1, 2020
• Primary Completion (Anticipated): March 1, 2021
• Study Completion (Anticipated): October 1, 2021

Study Registration Dates

• First Submitted: June 20, 2019
• First Submitted That Met QC Criteria: June 21, 2019
• First Posted (Actual): June 24, 2019

Study Record Updates

• Last Update Posted (Actual): June 24, 2019
• Last Update Submitted That Met QC Criteria: June 21, 2019
• Last Verified: June 1, 2019

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Body Weight Changes; Body Weight; Weight Gain
• Other Study ID Numbers: CT/688/000000/16

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No