Relations between polymorphisms in drug-metabolising enzymes and toxicity of chemotherapy with cyclophosphamide, thiotepa and carboplatin.
OBJECTIVE
High-dose chemotherapy with cyclophosphamide, thiotepa and carboplatin (CTC) has been developed as a possible curative treatment modality in several solid tumours. However, a large interindividual variability in toxicity is encountered in high-dose chemotherapy. A priori identification of patients at risk for toxicity could be an attractive prospect. Genotyping of genes encoding drug-metabolising enzymes might provide such a tool.


METHODS
We assessed 16 selected polymorphisms in nine genes (CYP2B6, CYP2C9, CYP2C19, CYP3A4, CYP3A5, GSTA1, GSTP1, ALDH1A1 and ALDH3A1) of putative relevance in CTC metabolism using polymerase chain reaction and DNA sequencing in 113 patients who were treated with high-dose chemotherapy regimens based on CTC.


RESULTS
Patients heterozygous for the ALDH3A1*2 allele (allelic frequency 21.2%) had an increased risk of haemorrhagic cystitis when compared with patients with wild-type alleles [5/38 vs. 1/70; odds ratio (OR): 11.95, 95% confidence interval (CI): 1.18-120.56; P=0.04]. Furthermore, patients heterozygous for the ALDH1A1*2 allele (allelic frequency 5.8%) had an increased risk of liver toxicity when compared with patients with wild-type alleles (6/13 vs. 19/99; OR: 5.13, 95% CI: 1.30-20.30; P=0.02). No other relations reached significance.


CONCLUSIONS
Patients heterozygous for the ALDH3A1*2 and ALDH1A1*2 allele have an increased risk of haemorrhagic cystitis and liver toxicity, respectively, compared with patients with wild-type alleles when treated with a high-dose chemotherapy combination of CTC. Pharmacogenetic approaches can identify patients who are at risk of experiencing toxic side effects in high-dose chemotherapy.
Department of Pharmacy and Pharmacology, The Netherlands Cancer Institute/Slotervaart Hospital, The Netherlands. Corine.Ekhart@slz.nl
Corine
C
Ekhart
Sjoerd
S
Rodenhuis
Paul H M
PH
Smits
Jos H
JH
Beijnen
Alwin D R
AD
Huitema
D000293:Adolescent; D000328:Adult; D016190:Carboplatin / Q000008:administration & dosage / Q000009:adverse effects* / Q000494:pharmacology / Q000627:therapeutic use; D003520:Cyclophosphamide / Q000008:administration & dosage / Q000009:adverse effects* / Q000494:pharmacology / Q000627:therapeutic use; D005260:Female; D005787:Gene Frequency; D005838:Genotype; D006801:Humans; D008658:Inactivation, Metabolic / Q000235:genetics*; D008297:Male; D008875:Middle Aged; D009369:Neoplasms / Q000188:drug therapy* / Q000235:genetics; D020641:Polymorphism, Single Nucleotide / Q000235:genetics*; D013852:Thiotepa / Q000008:administration & dosage / Q000009:adverse effects* / Q000494:pharmacology / Q000627:therapeutic use
D003520:Cyclophosphamide; D013852:Thiotepa; D016190:Carboplatin