Ten-year survival after randomized comparison of imatinib (IM) 400 mg vs. IM 800 mg vs. IM + IFN vs. IM + Ara C vs. IM after IFN in chronic myeloid leukemia (CML)

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Background: It is unclear whether IM 400 mg is the optimum choice for the successful treatment of CML. Treatment optimization was therefore attempted. Methods: From July 2002 to March 2012, 1551 newly diagnosed patients in chronic phase (CP) were randomized into a 5-arm study to analyze 2 IM doses and 3 combinations. 1536 patients were evaluable, 400 for IM 400 mg, 420 for IM 800 mg, 430 for IM + Interferon (IFN), 158 for IM + Ara C and 128 for IM after IFN. Recruitment to the latter two arms was stopped after a pilot phase. Results: 10-year overall survival (OS) of all patients was 82%, 10-year progression free survival (PFS) 80%. 10-year OS was 80% with IM 400 mg, 79% with IM 800 mg, 84% with IM + IFN, 84% with IM + Ara C and 79% with IM after IFN. The differences were not significant. 10-year PFS was 80% with IM 400mg, 77% with IM 800mg, 83% with IM + IFN, 82% with IM + Ara C and 75% with IM after IFN. The differences were not significant either. Survival with any treatment was not significantly different from IM 400mg at any risk level by any risk score (Euro Sokal, EUTOS, ELTS). 87 patients progressed to blast crisis (BC). The 10-year cumulative incidence of BC was 5.8% (95% CI: 4.7%; 7.1%) equally distributed across treatment arms. Most BC occurred in the first 2 years. Median survival after BC was 7.9 months across treatment arms. 275 patients have died, 23 after stem cell transplantation in first CP. Two thirds of deaths were unrelated to CML. Incidence of death due to CML by competing risk analysis with death unrelated to CML as competing risk was not different between the 5-treatment arms. 10-year relative survival probability was 92% when compared to matched general population data. Patients reaching the cytogenetic or molecular response landmarks according to European LeukemiaNet criteria ( < 10% BCR-ABL IS at 3 months, < 1% BCR-ABL IS or complete cytogenetic remission at 6 months, < 0.1% BCR-ABL IS (MMR) at 12 months) had a significantly better survival than those not reaching the landmarks regardless of therapy. Conclusions: In conclusion, outcome of CML is currently more determined by prognostic markers than by choice of therapy. IM400 mg remains an excellent choice for initial therapy of CP-CML. Clinical trial information: NCT00055874.

Secondary malignancies in chronic myeloid leukemia patients after imatinib-based treatment: long-term observation in CML Study IV

Treatment of chronic myeloid leukemia (CML) has been profoundly improved by the introduction of tyrosine kinase inhibitors (TKIs). Long-term survival with imatinib is excellent with a 8-year survival rate of ∼88%. Long-term toxicity of TKI treatment, especially carcinogenicity, has become a concern. We analyzed data of the CML study IV for the development of secondary malignancies. In total, 67 secondary malignancies were found in 64 of 1525 CML patients in chronic phase treated with TKI (n=61) and interferon-α only (n=3). The most common malignancies (n⩾4) were prostate, colorectal and lung cancer, non-Hodgkin's lymphoma (NHL), malignant melanoma, non-melanoma skin tumors and breast cancer. The standardized incidence ratio (SIR) for all malignancies excluding non-melanoma skin tumors was 0.88 (95% confidence interval (0.63-1.20)) for men and 1.06 (95% CI 0.69-1.55) for women. SIRs were between 0.49 (95% CI 0.13-1.34) for colorectal cancer in men and 4.29 (95% CI 1.09-11.66) for NHL in women. The SIR for NHL was significantly increased for men and women. An increase in the incidence of secondary malignancies could not be ascertained. The increased SIR for NHL has to be considered and long-term follow-up of CML patients is warranted, as the rate of secondary malignancies may increase over time.

Additional mutations in SRSF2, ASXL1 and/or RUNX1 identify a high-risk group of patients with KIT D816V(+) advanced systemic mastocytosis

Most patients with KIT D816V(+) advanced systemic mastocytosis (SM) are characterized by somatic mutations in additional genes. We sought to clarify the prognostic impact of such mutations. Genotype and clinical characteristics of 70 multi-mutated KIT D816V(+) advanced SM patients were included in univariate and multivariate analyses. The most frequently identified mutated genes were TET2 (n=33 of 70 patients), SRSF2 (n=30), ASXL1 (n=20), RUNX1 (n=16) and JAK2 (n=11). In univariate analysis, overall survival (OS) was adversely influenced by mutations in SRSF2 (P<0.0001), ASXL1 (P=0.002) and RUNX1 (P=0.03), but was not influenced by mutations in TET2 or JAK2. In multivariate analysis, SRSF2 and ASXL1 remained the most predictive adverse indicators concerning OS. Furthermore, we found that inferior OS and adverse clinical characteristics were significantly influenced by the number of mutated genes in the SRSF2/ASXL1/RUNX1 (S/A/R) panel (P<0.0001). In conclusion, the presence and number of mutated genes within the S/A/R panel are adversely associated with advanced disease and poor survival in KIT D816V(+) SM. On the basis of these findings, inclusion of molecular markers should be considered in upcoming prognostic scoring systems for patients with SM.

Prognosis of long-term survival considering disease-specific death in patients with chronic myeloid leukemia

In patients with chronic myeloid leukemia (CML), first-line imatinib treatment leads to 8-year overall survival (OS) probabilities above 80%. Many patients die of reasons unrelated to CML. This work tackled the reassessment of prognosis under particular consideration of the probabilities of dying of CML. Analyses were based on 2290 patients with chronic phase CML treated with imatinib in six clinical trials. 'Death due to CML' was defined by death after disease progression. At 8 years, OS was 89%. Of 208 deceased patients, 44% died of CML. Higher age, more peripheral blasts, bigger spleen and low platelet counts were significantly associated with increased probabilities of dying of CML and determined a new long-term survival score with three prognostic groups. Compared with the low-risk group, the patients of the intermediate- and the high-risk group had significantly higher probabilities of dying of CML. The score was successfully validated in an independent sample of 1120 patients. In both samples, the new score differentiated probabilities of dying of CML better than the Sokal, Euro and the European Treatment and Outcome Study (EUTOS) score. The new score identified 61% low-risk patients with excellent long-term outcome and 12% high-risk patients. The new score supports the prospective assessment of long-term antileukemic efficacy and risk-adapted treatment.

Impact of unbalanced minor route versus major route karyotypes at diagnosis on prognosis of CML

Major route additional cytogenetic aberrations (ACA) at diagnosis of chronic myeloid leukaemia (CML) indicate an increased risk of progression and shorter survival. Since major route ACA are almost always unbalanced, it is unclear whether other unbalanced ACA at diagnosis also confer an unfavourable prognosis. On the basis of 1348 Philadelphia chromosome-positive chronic phase patients of the randomized CML study IV, we examined the impact of unbalanced minor route ACA at diagnosis versus major route ACA on prognosis. At diagnosis, 1175 patients (87.2 %) had a translocation t(9;22)(q34;q11) and 74 (5.5 %) a variant translocation t(v;22) only, while a loss of the Y chromosome (-Y) was present in addition in 44 (3.3 %), balanced or unbalanced minor route ACA each in 17 (1.3 %) and major route ACA in 21 (1.6 %) cases. Patients with unbalanced minor route ACA had no significantly different cumulative incidences of complete cytogenetic remission or major molecular remission and no significantly different progression-free survival (PFS) or overall survival (OS) than patients with t(9;22), t(v;22), -Y and balanced minor route karyotypes. In contrast, patients with major route ACA had a shorter OS and PFS than all other groups (all pairwise comparisons to each of the other groups: p ≤ 0.015). Five-year survival probabilities were for t(9;22) 91.4 % (95 % CI 89.5-93.1), t(v; 22) 87 % (77.2-94.3), -Y 89.0 % (76.7-97.0), balanced 100 %, unbalanced minor route 92.3 % (72.4-100) and major route 52.2 % (28.2-75.5). We conclude that only major route, but not balanced or unbalanced minor route ACA at diagnosis, has a negative impact on prognosis of CML.

Prognostic scores for patients with chronic myeloid leukemia under particular consideration of competing causes of death

Nowadays in many fields of medicine, prognostic scores are used to predict the outcome for individual patients. In chronic myeloid leukemia (CML), the Sokal, the Euro, and the EUTOS score are established prognostic scores which were addressed by the CML management recommendations of the European LeukemiaNet. This review provides a general definition of prognostic scores and explains their meaning. Main differences between the Sokal, the Euro, and the EUTOS score are highlighted. Due to the therapeutic success of tyrosine kinase inhibitors, the proportion of patients with causes of death unrelated to CML is growing. To assess the potential of a drug to prevent dying of CML, causes of death unrelated to CML need to be considered as competing risks. Supported by data of patients randomized to imatinib-based treatments within the German CML study IV, this review also explores the prognostic performance of the established scores if the primary event is death due to CML only and explains the implicit statistical particularities when treating other causes of death as competing risks. In the presence of competing risks, the application of both the cause-specific hazard model and the subdistribution hazard model is recommended when investigating the influence of prognostic factors on the event of interest. Another purpose of this work is to foster the ability of hematologists to interpret the outcome of a cause-specific hazard and a subdistribution hazard model and to understand the differences between them.

A multi-state model approach for prediction in chronic myeloid leukaemia

Multi-state models support prediction in medicine. With different states of disease, chronic myeloid leukaemia (CML) is particularly suited for the application of multi-state models. In this article, we tried to find a model for CML that allows predicting the prevalence of three different states (initial state of disease, remission and progression) in dependence on treatment, adjusted for age, sex and risk score. Based on the German CML Study IV, one of the largest randomised studies in CML, the model was able to represent the known effects of age and risk score on the probabilities of remission and progression. Patients achieving a major molecular remission had a better chance of surviving without progression, but this effect was not significant. Comparing treatments, patient of the high-dose arm had the greatest chance to be in the state "remission" at 5 years but did not seem to have an advantage considering "progression". The proposed illness-death model can be useful for predicting the course of CML based on the patient's individual covariates (trial registration: this is an explorative analysis of ClinicalTrials.gov Identifier: NCT00055874).

Older patients with chronic myeloid leukemia (≥65 years) profit more from higher imatinib doses than younger patients: a subanalysis of the randomized CML-Study IV

The impact of imatinib dose on response rates and survival in older patients with chronic myeloid leukemia in chronic phase has not been studied well. We analyzed data from the German CML-Study IV, a randomized five-arm treatment optimization study in newly diagnosed BCR-ABL-positive chronic myeloid leukemia in chronic phase. Patients randomized to imatinib 400 mg/day (IM400) or imatinib 800 mg/day (IM800) and stratified according to age (≥65 years vs. <65 years) were compared regarding dose, response, adverse events, rates of progression, and survival. The full 800 mg dose was given after a 6-week run-in period with imatinib 400 mg/day. The dose could then be reduced according to tolerability. A total of 828 patients were randomized to IM400 or IM800. Seven hundred eighty-four patients were evaluable (IM400, 382; IM800, 402). One hundred ten patients (29 %) on IM400 and 83 (21 %) on IM800 were ≥65 years. The median dose per day was lower for patients ≥65 years on IM800, with the highest median dose in the first year (466 mg/day for patients ≥65 years vs. 630 mg/day for patients <65 years). Older patients on IM800 achieved major molecular remission and deep molecular remission as fast as younger patients, in contrast to standard dose imatinib with which older patients achieved remissions much later than younger patients. Grades 3 and 4 adverse events were similar in both age groups. Five-year relative survival for older patients was comparable to that of younger patients. We suggest that the optimal dose for older patients is higher than 400 mg/day. ClinicalTrials.gov identifier: NCT00055874

Equivalence of BCR-ABL transcript levels with complete cytogenetic remission in patients with chronic myeloid leukemia in chronic phase

PURPOSE

Chronic myeloid leukemia (CML) patients are monitored by both cytogenetic and molecular assessments, although present guidelines appear to switch from cytogenetic to molecular criteria. Due to the increasing use of molecular measurements, it was the aim of this work to identify a BCR-ABL level according to the international scale (BCR-ABL(IS)) as an equivalent substitute for complete cytogenetic remission (CCyR).

METHODS

In total, 1,329 paired data from 557 patients of the German CML-Study IV were evaluated. The data set was divided into a learning set and a validation set. The best cutoff was determined applying a minimal p value approach to the Fisher test.

RESULTS

In the learning set, we found BCR-ABL(IS) values between 0.2 and 1.1 % were well suited for predicting a CCyR. In the validation set, the cutoff level of 1 % led to a mean concordance rate of 90.1 %.

CONCLUSIONS

Our results suggest that there is no one-to-one cutoff for BCR-ABL(IS) representing CCyR, but we advise to use the 1 % BCR-ABL(IS) in order to avoid misclassification of CCyR patients.

Distinct characteristics of e13a2 versus e14a2 BCR-ABL1 driven chronic myeloid leukemia under first-line therapy with imatinib

The vast majority of chronic myeloid leukemia patients express a BCR-ABL1 fusion gene mRNA encoding a 210 kDa tyrosine kinase which promotes leukemic transformation. A possible differential impact of the corresponding BCR-ABL1 transcript variants e13a2 ("b2a2") and e14a2 ("b3a2") on disease phenotype and outcome is still a subject of debate. A total of 1105 newly diagnosed imatinib-treated patients were analyzed according to transcript type at diagnosis (e13a2, n=451; e14a2, n=496; e13a2+e14a2, n=158). No differences regarding age, sex, or Euro risk score were observed. A significant difference was found between e13a2 and e14a2 when comparing white blood cells (88 vs. 65 × 10(9)/L, respectively; P<0.001) and platelets (296 vs. 430 × 10(9)/L, respectively; P<0.001) at diagnosis, indicating a distinct disease phenotype. No significant difference was observed regarding other hematologic features, including spleen size and hematologic adverse events, during imatinib-based therapies. Cumulative molecular response was inferior in e13a2 patients (P=0.002 for major molecular response; P<0.001 for MR4). No difference was observed with regard to cytogenetic response and overall survival. In conclusion, e13a2 and e14a2 chronic myeloid leukemia seem to represent distinct biological entities. However, clinical outcome under imatinib treatment was comparable and no risk prediction can be made according to e13a2 versus e14a2 BCR-ABL1 transcript type at diagnosis. (clinicaltrials.gov identifier:00055874).

Deep Molecular Response Is Reached by the Majority of Patients Treated With Imatinib, Predicts Survival, and Is Achieved More Quickly by Optimized High-Dose Imatinib: Results From the Randomized CML-Study IV

Purpose

Deep molecular response (MR4.5) defines a subgroup of patients with chronic myeloid leukemia (CML) who may stay in unmaintained remission after treatment discontinuation. It is unclear how many patients achieve MR4.5 under different treatment modalities and whether MR4.5 predicts survival.

Patients and Methods

Patients from the randomized CML-Study IV were analyzed for confirmed MR4.5 which was defined as ≥ 4.5 log reduction of BCR-ABL on the international scale (IS) and determined by reverse transcriptase polymerase chain reaction in two consecutive analyses. Landmark analyses were performed to assess the impact of MR4.5 on survival.

Results

Of 1,551 randomly assigned patients, 1,524 were assessable. After a median observation time of 67.5 months, 5-year overall survival (OS) was 90%, 5-year progression-free-survival was 87.5%, and 8-year OS was 86%. The cumulative incidence of MR4.5 after 9 years was 70% (median, 4.9 years); confirmed MR4.5 was 54%. MR4.5 was reached more quickly with optimized high-dose imatinib than with imatinib 400 mg/day (P = .016). Independent of treatment approach, confirmed MR4.5 at 4 years predicted significantly higher survival probabilities than 0.1% to 1% IS, which corresponds to complete cytogenetic remission (8-year OS, 92% v 83%; P = .047). High-dose imatinib and early major molecular remission predicted MR4.5. No patient with confirmed MR4.5 has experienced progression.

Conclusion

MR4.5 is a new molecular predictor of long-term outcome, is reached by a majority of patients treated with imatinib, and is achieved more quickly with optimized high-dose imatinib, which may provide an improved therapeutic basis for treatment discontinuation in CML.

Younger patients with chronic myeloid leukemia do well in spite of poor prognostic indicators: results from the randomized CML study IV

Since the advent of tyrosine kinase inhibitors, the impact of age on outcome of chronic myeloid leukemia (CML) patients has changed. We therefore analyzed patients from the randomized CML study IV to investigate disease manifestations and outcome in different age groups. One thousand five hundred twenty-four patients with BCR-ABL-positive chronic phase CML were divided into four age groups: (1) 16–29 years, n = 120; (2) 30–44 years, n = 383; (3) 45–59 years, n = 495; and (4) ≥60 years, n = 526. Group 1 (adolescents and young adults (AYAs)) presented with more aggressive disease features (larger spleen size, more frequent symptoms of organomegaly, higher white blood count, higher percentage of peripheral blasts and lower hemoglobin levels) than the other age groups. In addition, a higher rate of patients with BCR-ABL transcript levels >10 % on the international scale (IS) at 3 months was observed. After a median observation time of 67.5 months, no inferior survival and no differences in cytogenetic and molecular remissions or progression rates were observed. We conclude that AYAs show more aggressive features and poor prognostic indicators possibly indicating differences in disease biology. This, however, does not affect outcome.

The EUTOS prognostic score: review and validation in 1288 patients with CML treated frontline with imatinib

The introduction of tyrosine kinase inhibitors (TKI) in the treatment of Philadelphia chromosome-positive (Ph+) chronic myeloid leukemia (CML) has revolutionized the outcome, but the prognosis of the disease is still based on prognostic systems that were developed in the era of conventional chemotherapy and interferon (IFN)-alfa. A new prognostic score including only two variables, spleen size and basophils, was developed for the prediction of complete cytogenetic response (CCyR) and progression-free survival (PFS). The score was based on a large series of patients who were enrolled in prospective multicenter studies of first-line imatinib treatment. The prognostic value of the EUTOS (European Treatment and Outcome Study for CML) score has now been tested in an independent, multicenter, multinational series of 1288 patients who were treated first-line with imatinib outside prospective studies. It was found that also in these patients, the EUTOS prognostic score was predictive for CCyR, PFS and overall survival (OS). In addition, the prognostic value of the score was reported to be significant in seven of the eight other independent studies of almost 2000 patients that were performed in Europe, the Americas and Asia. The EUTOS risk score is a valid tool for the prediction of the therapeutic effects of TKI, particularly imatinib.

Effect of dose-optimized imatinib (IM) 800 mg on deep molecular responses (CMR 4.5) and prediction of survival: Results from the randomized CML-study IV

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Background: Since complete molecular remission (CMR 4.5) defines a subgroup of patients who may stay in remission even after discontinuation of treatment, we analysed whether CMR 4.5 is reached faster with dose optimized IM 800 mg and whether the achievement of CMR 4.5 at specified points in time results in better survival than the achievement of less deep remissions. Methods: Confirmed CMR 4 and CMR 4.5 are defined as ≤ 0.01% BCR-ABL IS or ≥ 4 log reduction and ≤ 0.0032% BCR-ABL IS or ≥ 4.5 log reduction, respectively, from standardized baseline as determined by real-time PCR in 2 independent analyses. Details on CML-Study IV have been published (Hehlmann et al., JCO 2011). Cumulative incidences were estimated under consideration of competing risks. Landmark analyses were performed to evaluate the prognostic impact of different remissions at 4 years on survival. Results: Of 1551 randomized patients with newly diagnosed chronic phase CML 1525 were evaluable. Median age was 52 years, 88% were EUTOS low risk, 12% high risk. 113 patients were transplanted (73 in first chronic phase), 246 received 2nd generation TKI. 152 patients have died. After a median observation time of 67.5 months, 6-year OS was 88.2%.CMR 4.5 was reached after a median of about 76.1 months with IM 800 and 107.3 months with IM 400. EUTOS low-risk patients reached all remissions faster than high-risk patients. Independent of treatment approach CMR 4.5 at 4 years predicted OS significantly better than complete cytogenetic remission (p=0.043), but not significantly better than major molecular remission (MMR) or CMR4. After a median observation of 3.9 years 1 of 626 patients with CMR 4 has progressed. Only six of the 394 patients with CMR 4.5 have died after a median observation time of 3.0 years, no patient has progressed. An additional finding was that achieving MMR at 3 and at 6 months predicts faster achievement of CMR 4.5. Conclusions: We conclude that dose optimized IM 800 induces CMR 4.5 faster than IM 400 and that CMR 4.5 at 4 years is associated with a survival advantage. Dose optimized IM 800 may provide an improved therapeutic basis for treatment discontinuation in patients with CML. Clinical trial information: NCT00055874.

The quantitative level of T315I mutated BCR-ABL predicts for major molecular response to second-line nilotinib or dasatinib treatment in patients with chronic myeloid leukemia

The BCR-ABL T315I mutation causes resistance to imatinib, nilotinib and dasatinib in chronic myeloid leukemia. Forty BCR-ABL positive patients with imatinib resistance were analyzed for T315I mutated clones after six months on nilotinib or dasatinib treatment by quantitative allele-specific ligation polymerase chain reaction with a sensitivity of 0.05%. Ligation polymerase chain reaction revealed 10 patients with more than 10(-5) BCR-ABL(T315I%)/GUS (high levels), none of whom achieved major molecular response after 12 months, and a further 8 patients with 10(-5) or below BCR-ABL(T315I%)/GUS (low levels) who all achieved major molecular response (P<0.001). A second independent group showed molecular response in one of 12 patients with high levels and 5 of 8 patients with low levels (P=0.018). Combining the groups resulted in a sensitivity and specificity of 92.9% and 87.5%, respectively. We conclude that the quantitative level of mutant T315I allele is predictive of major molecular response at 12 months on second-line nilotinib or dasatinib treatment. www.clinicaltrials.gov: CT00109707, NCT00384228, CA180013, CA180005 CA180006.

Acute Myeloid Leukemia (AML): different treatment strategies versus a common standard arm--combined prospective analysis by the German AML Intergroup

PURPOSE

Identifying true therapeutic progress in patients with acute myeloid leukemia (AML) requires a comparison of treatment strategies and results on the basis of uniform patient selection. To foster comparability across five clinical studies, we introduced a common standard arm combined with a general upfront randomization and performed prospective analyses with adjustment for differences in prognostic baseline characteristics.

PATIENTS AND METHODS

Whereas the studies' own regimens differed in chemotherapies, risk adaption, and guidelines for allogeneic stem-cell transplantation, the standard arm contained uniform cytarabine- and anthracycline-based standard-dose remission induction and high-dose consolidation courses.

RESULTS

Of 2,995 evaluable patients aged 16 to 60 years, 290 patients were randomly assigned to the common standard arm. Seventy percent of the 290 achieved complete remissions (62% with complete recovery, 8% with incomplete recovery; 95% CI, 65% to 76%). Five-year survival probabilities were 44.3% (95% CI, 37.7% to 50.7%) for overall survival, 44.8% (95% CI, 37.0% to 52.2%) for relapse-free survival, and 31.5% (95% CI, 25.7% to 37.4%) for event-free survival. Neither the unadjusted survival probabilities of the Kaplan-Meier method nor their adjustment for prognostic variables in multiple Cox regression models led to statistically significant different results in the three survival end points when the outcomes of each study were compared with the standard arm.

CONCLUSION

A strictly prospective comparison of different treatment strategies in patients with AML did not show clinically relevant outcome differences when compared through a common standard treatment arm. The results provide a representative basis for further therapeutic approaches.

Clinical trials in chronic myeloid leukemia

The introduction of the tyrosine kinase inhibitor (TKI) imatinib in the treatment of Philadelphia chromosome-positive chronic myeloid leukemia (CML) has substantially improved the outcome of CML patients. Despite the positive results, problems and questions remained. This was the rationale to setup trials for treatment optimization, where imatinib was administered in higher dose and/or in combination with other therapy but where also new and potentially more efficacious second-generation TKI, nilotinib and dasatinib, were investigated. This review summarizes data of recently published first-line studies with the standard treatment imatinib 400 mg as one study arm. Results of randomized comparisons to higher-dose imatinib treatment, nilotinib or dasatinib are discussed. With regard to outcome interpretation, general aspects on statistical issues and endpoint definitions are put into focus. Considering decidedly increased longevity thanks to TKI treatment, future research should include the evaluation of the quality of life (QoL). Relating also to QoL, safe ways of drug discontinuation need to be investigated.