Conference Coverage

Platelet glycoprotein genotypes predict responses to ITP therapy



– For patients with immune thrombocytopenia (ITP), platelet glycoprotein genotypes may predict effectiveness of specific therapies, according to investigators.

Dr. Irina Zotova of the Russian Research Institute of Hematology and Transfusiology of FMBA in Saint Petersburg Will Pass/MDedge News

Dr. Irina Zotova

Significant relationships were detected between allelic polymorphisms of glycoprotein genes and durable responses to corticosteroids, thrombopoietin receptor agonists (aTPOr), and splenectomy, reported lead author Irina Zotova, MD, of the Russian Research Institute of Hematology and Transfusiology, Federal Biomedical Agency, in Saint Petersburg and colleagues.

These findings could guide clinical decision making in ITP, according to Dr. Zotova.

“Currently, the choice of therapeutic approach to ITP treatment, especially the second-line, is empirical, and often based on the experience of the clinician,” Dr. Zotova said during her presentation at the annual congress of the European Hematology Association. “Recent studies have shown that ... genes coding for glycoprotein are involved in platelet function and are associated with different responses to ITP treatment. This provides an opportunity for an individual approach and personalization of ITP therapy in accordance with the genetic status of the patient.”

In the present study, the investigators used PCR-RFLP (polymerase chain reaction–restriction fragment length polymorphism) to determine GPIa A1648G and GPIIb 2622TG gene status in 81 patients with primary ITP and compared these genotypes with clinical responses.

All patients received first-line corticosteroid therapy. If necessary, second-line treatment was delivered. In total, 37 patients (46%) received aTPOr, while 22 patients (27%) underwent splenectomy. Responses were classified as durable response, nondurable response, or no response.

Analysis showed that a significantly greater proportion of patients who had durable responses to corticosteroid therapy exhibited a heterozygous GPIIb 2622TG genotype, compared with patients who had nondurable responses (72.2% vs. 30.9%; odds ratio, 5.8; P = .005).

For second-line responses, patients who had durable response to aTPOr were much more likely to be homozygous for the GPIa A1648G than nonresponders (87.5% vs. 20.0%; OR, 28.0; P = .005). More strikingly, all patients who achieved durable responses to splenectomy had the GPIa A1648G genotype, compared with just 44% of nonresponders (OR, 33.0; P = .005).

“Gentoyping for the GPIIb T2622G and GPIa A1648G polymorphisms allows [clinicians] to predict the response to first-line and second-line treatment, giving the possibility to stratify patients to groups with favorable and unfavorable courses of the disease,” Dr. Zotova concluded.

Dr. János Kappelmayer of the University of Debrecen, Hungary, Will Pass/MDedge News

Dr. János Kappelmayer

Session moderator János Kappelmayer, MD, of the University of Debrecen (Hungary) highlighted a key opportunity presented by the study. “I think that one important aspect of these findings could be that splenectomy is an irreversible procedure, so one can exclude those patients who will not benefit from splenectomy,” he said. “I think this is a real advantage.”

The investigators reported no study funding or conflicts of interest.

SOURCE: Zotova I et al. EHA Congress, Abstract S848.

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