Pharmacogenomics of thiopurines on Kosovo population

Pasha, Flaka (author), Mlinarič Raščan, Irena (mentor), Krasniqi, Shaip (comentor)

This dissertation evaluates the efficacy and safety of thiopurine treatment in patients with acute lymphoblastic leukemia (ALL), inflammatory bowel disease (IBD), and autoimmune disorders in Kosovo. Herein, we present identified and validated genetic polymorphisms affecting thiopurine metabolism, and correlations of thiopurine-related pharmacogenomic biomarkers with adverse treatment outcomes. We assessed the efficacy and safety of thiopurine treatment among children diagnosed with ALL in Kosovo (N=225), for the past 15-years. We documented 61% remission rate (95% CI: 54-67%), 11% relapse rate (95% CI: 7-16%), 20% mortality (95% CI: 13-26%), 55% 2-year event-free survival (EFS) (95% CI: 48-61%), 40% 5-year EFS (95% CI: 34-46%), 61% 2-year overall survival (OS) (95% CI: 55-68%), and 46% 5-year OS (95% CI: 40-53%). The survival rates were significantly lower compared to the existing literature. Furthermore, in the healthy population of Kosovo (N=299), we evaluated polymorphisms and variants influencing thiopurine metabolism. We observed the following minor allele frequencies (MAF): TPMT*2 - 0%, TPMT*3A - 2%, TPMT*3C - 0.1%, PACSIN2 rs2413739 - 48.8%, ITPA rs1127354 - 4%, MTHFR rs1801133 - 49.8%, and MTHFR rs1801131 - 27.4%. We identified five variants in NUDT15 gene, hence: rs45465203 - 13.5%, rs61973267 - 9%, rs79687000 - 2%, rs377238223 - 0.4%, and rs746071566 - 0.4%. MAFs for NUDT15 rs61973267, PACSIN2 rs2413739 and MTHFR rs1801133 were significantly higher compared to the global population (p<0.0001), while the MAF for ITPA rs1127354 was significantly lower than global and European population. Lastly, we evaluated the correlation between thiopurine-related pharmacogenomic biomarkers with biochemical and hematological parameters in 69 patients diagnosed with ALL, IBD and autoimmune disorders in Kosovo (13 ALL children; 56 adults with internal medicine disorders). We identified 11 patients with 6-TGN levels under thiopurine therapeutic range, 7 non-compliant patients, 2 non-responsive patients, 27 patients with 6-TGN levels >450 pmol/8×108 RBC, potentially under risk of myelotoxicity, and 6 patients with 6-MeMP levels >5700pmol/8×108 RBC under the risk of hepatotoxicity. We further carried out the correlation analyses of pharmacogenomic and biochemical biomarkers, indicating thiopurine-induced leukopenia and potential hepatotoxicity in a subset of patients. Results included in this dissertation set the foundation for establishing pharmacogenomic biomarkers and therapeutic drug monitoring services in Kosovo healthcare system, thus improving safety and efficacy of thiopurine-treated prospective patients through precision medicine.

• Language: English
• Keywords: thiopurines, pharmacogenomics, therapeutic drug monitoring, overall survival, adverse outcomes
• Work type: Doctoral dissertation
• Organization: FFA - Faculty of Pharmacy
• Year: 2025
• PID: 20.500.12556/RUL-166819
• Publication date in RUL: 27.01.2025

Secondary language

• Language: Slovenian
• Title: Farmakogenomika tiopurinov v populaciij Kosova

Abstract

Disertacija predstavlja študijo učinkovitosti in varnosti zdravljenja s tiopurini pri bolnikih z akutno limfoblastno levkemijo (ALL), kronično vnetno črevesno boleznijo (KVČB) in avtoimunskimi stanji na Kosovu V študiji prikažemo identificirane in validirane genetske polimorfizme, ki vplivajo na presnovo tiopurina in korelacijo s tiopurinom povezanih farmakogenomskih biomarkerjev z neželenimi izidi zdravljenja pri bolniki z ALL. Ocenili smo učinkovitost in varnost zdravljenja s tiopurinom pri otrocih z diagnozo ALL na Kosovu (N=225) v zadnjih 15 letih. Dokumentirali smo 61% stopnjo remisije (95% CI: 54-67%), 11% stopnjo recidivov (95% CI: 7-16%), 20% umrljivost (95% CI: 13-26%), 55% 2-letno preživetje brez dogodka (EFS) (95% CI: 48-61%), 40 % 5-letno EFS (95% CI: 34-46%), 61 % 2-letno celokupno preživetje (OS) (95% CI: 55-68%), in 46 % 5-letno OS (95% CI: 40-53%). Stopnje preživetja so bile znatno nižje v primerjavi z rezultati obstoječe literature. Nadalje smo ovrednotili polimorfizme in različice, ki vplivajo na presnovo tiopurina v zdravi populaciji Kosova (N=299). Določili smo naslednje frekvence alelov (MAF): TPMT*2 - 0%, TPMT*3A - 2%, TPMT*3C - 0,1%, PACSIN2 rs2413739 - 48,8%, ITPA rs1127354 - 4%, MTHFR rs1801133 - 49,8%, in MTHFR rs1801131 - 27,4 %. Identificirali smo pet različic NUDT15 genain sicer: rs45465203 - 13,5 %, rs61973267 - 9 %, rs79687000 - 2 %, rs377238223 - 0,4 % in rs746071566 - 0,4 %. MAF za NUDT15 rs61973267, PACSIN2 rs2413739 in MTHFR rs1801133 so bili signifikantno višji v primerjavi s pojavnostjo v svetovni populaciji (p<0,0001), medtem ko je bil MAF za ITPA rs1127354 bistveno nižji od pojavnosti v svetovni in evropski populaciji. Nadalje smo ovrednotili korelacijo med genetskimi polimorfizmi, ki vplivajo na presnovo tiopurinov, aktivnost TPMT in raven metabolitov tiopurina, z biokemiskimi in hematološkimi parametri pri 69 bolnikih z diagnozo ALL, KVČB in avtoimunskih motenj na Kosovu (13 otrok ALL; 56 odraslih z motnjami interne medicine). Identificirali smo 11 bolnikov, ki so imeli koncentracijo 6-TGN pod terapevtskim nivojem, 7 bolnikov brez kompliance in 2 neodzivna bolnika. Nadalje smo identificirali 27 bolnikov z ravnmi 6-TGN >450 pmol/8×108 eritrocitov, pri katerih obstaja potencialno tveganje za mielotoksičnost, in 6 bolnikov z ravnmi 6-MeMP > 5700 pmol/8×108 eritrocitov podvrženih tveganju za hepatotoksičnost. Nadalje smo izvedli korelacijske analize farmakogenomskih in biokemičnih biomarkerjev, ki kažejo na levkopenijo, povzročeno s tiopurinom in potencialno hepatotoksičnost pri podskupini bolnikov. Rezultati, vključeni v disertacijo, so postavili temelje za vzpostavitev farmakogenomskih testiranj in storitev spremljanja terapevtskih zdravil v kosovskem zdravstvenem sistemu. Uvajanja principov personalizirane terapije bo omogočilo izboljšanje varnosti in učinkovitosti zdravljenja s tiopurini.

• Keywords: tiopurini, farmakogenomika, terapevtsko spremljanje zdravil, celokupno preživetje, neželeni učinki