Real World Outcomes of Chronic Myeloid Leukemia in Era of Tyrosine Kinase Inhibitors a Single Center Experience

Introduction: Obtaining a major molecular response (MMR) correlates with a higher probability of achieving a complete molecular response (CMR) and suboptimal molecular responses are associated with increased risk of resistance.

Methods: We retrospectively analyzed patients with a diagnosis of chronic myeloid leukemia who were treated at Penn State Cancer Institute between January 2008 to December 2018. These patients had bone marrow biopsy for confirmation for diagnosis of CML and were monitored by bcr-abl PCR to document molecular response: Complete (CMR ) vs. Major (MMR).

Results: A total of 74 patients F :32; M:42 were diagnosed with CML between 2008 and 2018 with median age at diagnosis 52 years (22yrs -89yrs). The majority of these patients had CML in chronic phase (n=68;92% ) and 4%(n=3) were in accelerated phase (CML AP) and 4% (n=3) had blastic phase (CML BC). High Sokal score was seen in 42% (31/74) patients with concordance seen in most patients with high Sokal scores.Highest Sokal score was infinity in a patient with massively enlarged spleen with Hasford score 2179. Highest Hasford score was 5625 with discordant Sokal score of 558. Imatinib was used in front line in 45 /74 patients. Dasatinib and nilotinib were used as first line 18 vs 5, second line in 19 vs 6 and third line in 3 vs 7 patients. Ponatinib was used second line in 2 patients vs. third, forth and fifth line in 1 patient each.

A total of 8 patients received allogeneic transplant ( 1 cord ) and all 8/8 achieved CMR remained in CR for medan of 12 years . Only 30/66(45%) achieved CMR who did not undergo transplant and 24/66 (36%) achieved MMR and 10 (15%) patients did not achieve MMR and remaining had progression.

TKI resistance and TKI intolerance was seen in 7/66 (4.6%) patients. second cancers were seen in 9% (n=6) patients.

Conclusion: Allogeneic transplant still appears to have role to achieve long term CR. Use of drugs targeting CML leukemia stem cells along with TKIs may be needed to yield more complete metabolic responses (CMR) cure CML.

Rakszawski:SeaGen: Consultancy, Speakers Bureau. Claxton:Astellas: Research Funding. Rybka:Merck: Research Funding; Penn State Health: Current Employment; Spark Therapeutics: Consultancy; Spark Therapeutics: Membership on an entity's Board of Directors or advisory committees.