The risk of Sokal score misclassification was particularly notable among elderly patients.

“In elderly CML patients treated with imatinib or nilotinib as frontline therapy, the ELTS score was able to predict the achievement of major molecular response and long-term leukemia-related survival [= .027], whereas the Sokal score was not [= .15, not significant],” Dr Castagnetti explained. “Consequently, in elderly patients, the use of ELTS score is strongly recommended to assess baseline disease risk and to select patients as candidates for frontline treatment with second-generation TKIs, minimizing their risk of unnecessary overtreatment.”


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ELTS and Sokal scores differently weigh age, which likely explains their different predictive value, the authors hypothesized. The formulas for Sokal and ELTS scoring are described online.

The study analyzed data from 904 intention-to-treat (ITT) adult patients enrolled in 6 multicenter studies, 559 of whom were treated with imatinib and 345 who received nilotinib. The median patient age was 52 years (range, 18-86 years), with 70% of patients aged 30 years to 64 years and 22% aged 65 or older.

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At a median follow-up of 77 months (range, 24-109 months), the risk according to ELTS was 57% low-risk, 30% intermediate-risk and 13% high-risk, compared with 40% low-risk, 39% intermediate-risk and 21% high-risk with Sokal scores.Concordance was “good” between ELTS and Sokal scores for low- and high-risk categories among patients younger than 30 years, Dr Castagnetti noted.

But ELTS stratified elderly patients (age ≥ 65 years) as 24% low-risk, 54% intermediate-risk and 22% high-risk, compared with Sokal scoring of 9% low-risk, 70% intermediate-risk and 21% high-risk. Those risk distributions were “comparable” between patients treated with imatinib and nilotinib. Among elderly patients, “only 8% of low-ELTS patients had a low Sokal score, and only 48% of high-ELTS score patients had a high Sokal score,” he said.

Overall, both ELTS and Sokal scores can significantly predict different probabilities of major molecular response, overall survival, and leukemia-related deaths, but prognostic power was stronger for ELTS, particularly among elderly patients.

“Interestingly, in elderly patients, both scores predicted the OS, while only the ELTS score predicted a significantly different LRD probability (cumulative incidence 2%, 6%, and 14% in low-, intermediate-, and high-risk patients, respectively; = .049),” Dr Castagnetti reported. “The results were similar considering patients younger than 30 years, 30-59 years, or 60 years [or older].”

ELTS and bone marrow examinations demonstrating non–chronic-phase CML can help identify more precisely which patients might benefit from a second-generation TKI, new biomarkers that predict treatment outcomes even more powerfully are still needed, other researchers have noted.BCR-ABL1 transcript biomarkers and other cytogenetic abnormalities are under investigation as potentially predictive biomarkers.3

Disclosure: Dr Castagnetti disclosed consultancies and honoraria from Bristol Myers Squibb, Incyte, Pfizer, and Novartis. For a full list of disclosures, please refer to the original study abstract.

Read more of Cancer Therapy Advisor‘s coverage of the ASH 2018 meeting by visiting the conference page.

References

  1. Castagnetti F, Gugliotta G, Breccia M, et al. The use of EUTOS Long-Term Survival Score instead of Sokal Score is strongly advised in elderly chronic myeloid leukemia patients. Oral presentation at: American Society of Hematology 60th Annual Meeting & Exposition; December 1-4, 2018; San Diego, CA. Abstract 44.
  2. Tiribelli M, Bonifacio M, Calistri E, et al. EUTOS score predicts long-term outcome but not optimal response to imatinib in patients with chronic myeloid leukaemia. Leuk Res. 2013;37:1457-1460.
  3. Chopade P, Akard LP. Improving outcomes in chronic myeloid leukemia over time in the era of tyrosine kinase inhibitorsClin Lymph Myeloma Leuk. 2018;18(11):710-723.