Toxic death case in a patient undergoing gemcitabine-based chemotherapy in relation with cytidine deaminase downregulation.
Gemcitabine is an antimetabolite drug used in the treatment of various solid tumours, including lung, pancreatic or gynaecological cancers. Innovative combinational strategies (e.g. gemcitabine+capecitabine or gemcitabine+oxaliplatin) make gemcitabine an extensively prescribed drug now. Gemcitabine is characterized by a narrow therapeutic index, and its liver elimination depends upon a key enzymatic step, driven by cytidine deaminase (CDA). CDA is prone to gene polymorphism, including the 208A>G mutation, which can result in marked enzymatic deficiency with subsequent impact on drug exposure levels and related toxicities. We have developed a simple and inexpensive method to determine phenotypically CDA status in cancer patients, as an attempt to detect those at risk upon gemcitabine intake. Conjointly to genotypic investigations, this method was used to phenotype, in a retrospective setting, a female patient displaying extremely severe, and eventually lethal, toxicities after administration of a standard gemcitabine/carboplatin protocol. Phenotypic investigation showed a marked CDA deficiency (-75%) in this patient when compared with a reference, nontoxic population. Genetic studies undertaken next to screen mutations, possibly at the origin of this deficiency, showed heterozygosity for the 79A>C single-point mutation, whereas surprisingly the canonical CDA 208A>G polymorphism was not found. Taken together, this case report demonstrates, for the first time, that CDA downregulation can lead to toxic-death in patients exposed to gemcitabine. Besides, we showed here that our cost-effective and simple phenotypic approach should enable, in the future, the detection of deficient patients at risk upon gemcitabine administration.
Mercier
Cédric
C
EA3286, Pharmacokinetics Laboratory, Mediterranee University, Marseilles, France.
Raynal
Caroline
C
Dahan
Laetitia
L
Ortiz
Adrien
A
Evrard
Alexandre
A
Dupuis
Charlotte
C
Blesius
Aurore
A
Duluc
Muriel
M
Franceschini
Fleur
F
Giacometti
Sarah
S
Salas
Sébastien
S
Milano
Gérard
G
Favre
Roger
R
Seitz
Jean-François
JF
Ciccolini
Joseph
J
D000368:Aged; D003564:Cytidine Deaminase / Q000097:blood / Q000235:genetics*; D003841:Deoxycytidine / Q000009:adverse effects / Q000031:analogs & derivatives* / Q000627:therapeutic use; D015536:Down-Regulation / Q000187:drug effects*; D017809:Fatal Outcome; D005260:Female; D006801:Humans; D010641:Phenotype; D020641:Polymorphism, Single Nucleotide / Q000235:genetics; D012016:Reference Values; D000093542:Gemcitabine
D003841:Deoxycytidine; D003564:Cytidine Deaminase; D000093542:Gemcitabine