ESMO 2019 Congress | OncologyPRO

Abstract 1904

Background

The management of Chronic Myeloid Leukemia (CML) has undergone a paradigm shift with advent of the tyrosine kinase inhibitor (TKI), namely imatinib. Despite a high remission rate, a significant proportion of patients showed resistance and/or intolerance to imatinib therapy, be it primary or secondary. However, the scenario of resistance along with the prevalence and clinical route of CML in the Eastern part of India remains elusive. To observe the incidence of resistance to TKI after years of therapy, we performed a study in a tertiary cancer care centre, serving patients from Eastern Indian states as well as neighbor countries like Bangladesh and Bhutan. Based on the CML cases registered at the centre for the last 13 years, we performed a longitudinal assessment of the disease history and molecular management to portray the incidence of imatinib resistance in CML patients.

Methods

The methods in schematic are described below: No. of CML cases with disease history ↓ Patients showing loss of Major Molecular Response (MMR), detected by Real-Time quantitative PCR ↓ Mutation analysis in BCR-ABL kinase domain (KD) (by Sanger sequencing) ↓ Calculation of type and incidence of KD mutation ↓ The survival analyses performed by Kaplan-Meier analysis.

Results

The results are presented in tabular form as below:.Table: 1098P

No. of registered CML cases (2005-2017)	Median period of Imatinib treatment	No. of patients showing Loss of MMR (BCR-ABL >1.0%)	No. of patients undergoing BCR-ABL KD mutation testing (% affordability)	No. of patients showing BCR-ABL KD mutation	Patients with Imatinib failure but no detectable BCR-ABL KD mutation
986	26 months	101	20 (20%)	11 (55% of resistant pool)	9 (45% of resistant pool)

After years of therapy, KD mutations are seen in 55% of imatinib-resistant patients. The survival analysis showed significant difference between treatment-sensitive and –resistant pools.

Conclusions

The incidence of imatinib resistance has been increasingly detected in Eastern-Indian region after long term therapy with imatinib. However, the full scenario could not be depicted due to resource constraints. More numbers of patients are to be tested to achieve robust evidence.

Clinical trial identification

Editorial acknowledgement

Legal entity responsible for the study

The authors.

Funding

Has not received any funding.

Disclosure

All authors have declared no conflicts of interest.

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28 Sep 2019