A phase 2 trial of ponatinib in Philadelphia chromosome-positive leukemias.

BACKGROUND: Ponatinib is a potent oral tyrosine kinase inhibitor of unmutated and mutated BCR-ABL, including BCR-ABL with the tyrosine kinase inhibitor-refractory threonine-to-isoleucine mutation at position 315 (T315I). We conducted a phase 2 trial of ponatinib in patients with chronic myeloid leukemia (CML) or Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph-positive ALL). METHODS: We enrolled 449 heavily pretreated patients who had CML or Ph-positive ALL with resistance to or unacceptable side effects from dasatinib or nilotinib or who had the BCR-ABL T315I mutation. Ponatinib was administered at an initial dose of 45 mg once daily. The median follow-up was 15 months. RESULTS: Among 267 patients with chronic-phase CML, 56% had a major cytogenetic response (51% of patients with resistance to or unacceptable side effects from dasatinib or nilotinib and 70% of patients with the T315I mutation), 46% had a complete cytogenetic response (40% and 66% in the two subgroups, respectively), and 34% had a major molecular response (27% and 56% in the two subgroups, respectively). Responses were observed regardless of the baseline BCR-ABL kinase domain mutation status and were durable; the estimated rate of a sustained major cytogenetic response of at least 12 months was 91%. No single BCR-ABL mutation conferring resistance to ponatinib was detected. Among 83 patients with accelerated-phase CML, 55% had a major hematologic response and 39% had a major cytogenetic response. Among 62 patients with blast-phase CML, 31% had a major hematologic response and 23% had a major cytogenetic response. Among 32 patients with Ph-positive ALL, 41% had a major hematologic response and 47% had a major cytogenetic response. Common adverse events were thrombocytopenia (in 37% of patients), rash (in 34%), dry skin (in 32%), and abdominal pain (in 22%). Serious arterial thrombotic events were observed in 9% of patients; these events were considered to be treatment-related in 3%. A total of 12% of patients discontinued treatment because of an adverse event. CONCLUSIONS: Ponatinib had significant antileukemic activity across categories of disease stage and mutation status. (Funded by Ariad Pharmaceuticals and others; PACE ClinicalTrials.gov number, NCT01207440 .).

NIH-defined graft-versus-host disease and evidence for a potent graft-versus-leukemia effect in patients with acute lymphoblastic leukemia.

BACKGROUND: The prognostic value of the NIH consensus criteria for graft-versus-host disease (GVHD) is not well defined yet. PATIENTS AND METHODS: We analyzed NIH-defined GVHD in 147 acute lymphoblastic leukemia (ALL) patients. RESULTS: The cumulative incidence of classic acute GVHD (aGVHD), late aGVHD and chronic GVHD (cGVHD) was 63%, 12% and 41%, respectively. cGVHD was subclassified as classic versus overlap syndrome in 40% versus 60% of cases. In multivariate Cox regression analysis with GVHD as time-dependent covariate, classic aGVHD grade III/IV had a negative impact on overall survival (OS) due to higher non-relapse mortality. cGVHD of any grade was associated with superior OS, which was due to lower relapse incidence. Classic cGVHD versus overlap syndrome had no differential impact. In 44 patients without GVHD after transplant who received donor lymphocyte infusions (DLI), the cumulative incidence of classic aGVHD, late aGVHD or cGVHD was 60%, 5% and 57%. Occurrence of cGVHD after DLI was associated with improved OS due to lower relapse incidence. CONCLUSIONS: The NIH consensus criteria for GVHD clearly define prognostic subgroups in patients transplanted for ALL. The improved OS in patients developing cGVHD after transplant or DLI gives clear evidence for a potent graft-versus-leukemia effect in this indication.

Reduced-intensity conditioning using fludarabine and antithymocyte globulin alone allows stable engraftment in a patient with dyskeratosis congenita.

Dyskeratosis congenita (DC) is a rare inherited disorder characterized by the triad of nail dystrophy, mucosal leukoplakia, and reticular pigmentation. Bone marrow failure is the principal cause of early mortality, and stem cell transplantation is the only cure for these patients. However, the results of conventional hematopoietic stem cell transplantation (HSCT) for patients with DC are poor because of the high incidence of transplant-related complications. We describe the successful treatment of a 21-year-old male with DC by nonmyeloablative HSCT from a matched unrelated donor. The gene responsible for the X-linked form of DC was screened and hemizygosity for the mutation Gln31Lys was found, which is consistent with the diagnosis. The conditioning regimen consisted of only fludarabine and antithymocyte globulin. Additionally, a graft-versus-host disease (GVHD) prophylaxis was administered with cyclosporine A (CSA) and mycophenolate mofetil (MMF). The regimen was well tolerated, no severe posttransplantation complications were observed, and engraftment was rapid and complete (granulocytes on day +11 and platelets on day +13). Seven months after HSCT, the patient developed GVHD of the liver after tapering CSA which was successfully treated with prednisolone, CSA, and MMF. At the time of reporting, 3 years after HSCT, the patient remained in good clinical condition with minimal signs of chronic GVHD of the oral mucosa. Thus, we conclude that a low-intensity conditioning regimen might be sufficient to induce permanent engraftment by using matched unrelated donor HSCT in DC patients and may avoid severe organ toxicity. Although allogeneic HSCT in patients with DC will not cure the underlying genetic defect it may significantly prolong survival through effective therapy for hematologic complications.

Reactivation of hepatitis E infection in a patient with acute lymphoblastic leukaemia after allogeneic stem cell transplantation.

Hepatitis E virus (HEV) is the major cause of several outbreaks of waterborne hepatitis in tropical and subtropical countries and of sporadic cases of viral hepatitis in endemic and industrialised countries. Generally, HEV causes an acute self-limiting hepatitis. The clinical course is characterised by transient viraemia and transaminasaemia followed by a full hepatic recovery. Recent studies describe prolonged and chronic HEV infections in some immunosuppressed patients after solid organ transplantation. Here, an indigenous acute limited hepatitis E in a patient with Philadelphia chromosome-positive acute lymphoblastic leukaemia prior to allogeneic stem cell transplantation is reported. Fourteen weeks after stem cell transplantation, reappearance of HEV viraemia was observed, with increasing viral load and modestly elevated serum transaminases. Sequence analysis of the viral RNAs revealed a reactivation of endogenous HEV genotype 3, indicating viral persistence after recovery from acute hepatitis E.

Successful salvage treatment of disseminated cutaneous fusariosis with liposomal amphotericin B and terbinafine after allogeneic stem cell transplantation.

Fusarium infections are associated with high mortality after allogeneic stem cell transplantation. We report on successful treatment of a disseminated cutaneous Fusarium proliferatum infection using liposomal amphotericin B and terbinafine. In vitro susceptibility tests of antifungal drugs suggest that terbinafine is a potent additional antifungal drug for disseminated cutaneous fusariosis.

Treatment-free remission following frontline nilotinib in patients with chronic myeloid leukemia in chronic phase: results from the ENESTfreedom study.

The single-arm, phase 2 ENESTfreedom trial assessed the potential for treatment-free remission (TFR; i.e., the ability to maintain a molecular response after stopping therapy) following frontline nilotinib treatment. Patients with Philadelphia chromosome-positive chronic myeloid leukemia in chronic phase with MR4.5 (BCR-ABL1⩽0.0032% on the International Scale (BCR-ABL1IS)) and ⩾2 years of frontline nilotinib therapy were enrolled. Patients with sustained deep molecular response during the 1-year nilotinib consolidation phase were eligible to stop treatment and enter the TFR phase. Patients with loss of major molecular response (MMR; BCR-ABL1IS⩽0.1%) during the TFR phase reinitiated nilotinib. In total, 215 patients entered the consolidation phase, of whom 190 entered the TFR phase. The median duration of nilotinib before stopping treatment was 43.5 months. At 48 weeks after stopping nilotinib, 98 patients (51.6%; 95% confidence interval, 44.2-58.9%) remained in MMR or better (primary end point). Of the 86 patients who restarted nilotinib in the treatment reinitiation phase after loss of MMR, 98.8% and 88.4%, respectively, regained MMR and MR4.5 by the data cutoff date. Consistent with prior reports of imatinib-treated patients, musculoskeletal pain-related events were reported in 24.7% of patients in the TFR phase (consolidation phase, 16.3%).

In vivo eradication of human BCR/ABL-positive leukemia cells with an ABL kinase inhibitor.

BACKGROUND: The leukemia cells of approximately 95% of patients with chronic myeloid leukemia and 30%-50% of adult patients with acute lymphoblastic leukemia express the Bcr/Abl oncoprotein, which is the product of a fusion gene created by a chromosomal translocation [(9:22) (q34;q11)]. This oncoprotein expresses a constitutive tyrosine kinase activity that is crucial for its cellular transforming activity. In this study, we evaluated the antineoplastic activity of CGP57148B, which is a competitive inhibitor of the Bcr/Abl tyrosine kinase. METHODS: Nude mice were given an injection of the Bcr/Abl-positive human leukemia cell lines KU812 or MC3. Tumor-bearing mice were treated intraperitoneally or orally with CGP57148B according to three different schedules. In vitro drug wash-out experiments and in vivo molecular pharmacokinetic experiments were performed to optimize the in vivo treatment schedule. RESULTS: Treatment schedules administering CGP57148B once or twice per day produced some inhibition of tumor growth, but no tumor-bearing mouse was cured. A single administration of CGP57148B caused substantial (>50%) but short-lived (2-5 hours) inhibition of Bcr/Abl kinase activity. On the basis of the results from in vitro wash-out experiments, 20-21 hours was defined as the duration of continuous exposure needed to block cell proliferation and to induce apoptosis in these two leukemia cell lines. A treatment regimen assuring the continuous block of the Bcr/Abl phosphorylating activity that was administered over an 11-day period cured 87%-100% of treated mice. CONCLUSION: These data indicate that the continuous block of the oncogenic tyrosine kinase of Bcr/Abl protein is needed to produce important biologic effects in vivo.

Role of alpha1 acid glycoprotein in the in vivo resistance of human BCR-ABL(+) leukemic cells to the abl inhibitor STI571.

BACKGROUND: Chronic myeloid leukemia is caused by a chromosomal translocation that results in an oncogenic fusion protein, Bcr-Abl. Bcr-Abl is a tyrosine kinase whose activity is inhibited by the antineoplastic drug STI571. This drug can cure mice given an injection of human leukemic cells, but treatment ultimately fails in animals that have large tumors when treatment is initiated. We created a mouse model to explore the mechanism of resistance in vivo. METHODS Nude mice were injected with KU812 Bcr-Abl(+) human leukemic cells. After 1 day (no evident tumors), 8 days, or 15 days (tumors >1 g), mice were treated with STI571 (160 mg/kg every 8 hours). Cells recovered from relapsing animals were used for in vitro experiments. Statistical tests were two-sided. RESULTS: Tumors regressed initially in all STI571-treated mice, but all mice treated 15 days after injection of tumor cells eventually relapsed. Relapsed animals did not respond to further STI571 treatment, and their Bcr-Abl kinase activity in vivo was not inhibited by STI571, despite high plasma concentrations of the drug. However, tumor cells from resistant animals were sensitive to STI571 in vitro, suggesting that a molecule in the plasma of relapsed animals may inactivate the drug. The plasma protein alpha1 acid glycoprotein (AGP) bound STI571 at physiologic concentrations in vitro and blocked the ability of STI571 to inhibit Bcr-Abl kinase activity in a dose-dependent manner. Plasma AGP concentrations were strongly associated with tumor load. Erythromycin competed with STI571 for AGP binding. When animals bearing large tumors were treated with STI571 alone or with a combination of STI571 and erythromycin, greater tumor reductions and better long-term tumor-free survival (10 of 12 versus one of 13 at day 180; P:<.001) were observed after the combination treatment. CONCLUSION: AGP in the plasma of relapsed animals binds to STI571, preventing this compound from inhibiting the Bcr/Abl tyrosine kinase. Molecules such as erythromycin that compete with STI571 for binding to AGP may enhance the therapeutic potential of this drug.

Long-term benefits and risks of frontline nilotinib vs imatinib for chronic myeloid leukemia in chronic phase: 5-year update of the randomized ENESTnd trial.

In the phase 3 Evaluating Nilotinib Efficacy and Safety in Clinical Trials-Newly Diagnosed Patients (ENESTnd) study, nilotinib resulted in earlier and higher response rates and a lower risk of progression to accelerated phase/blast crisis (AP/BC) than imatinib in patients with newly diagnosed chronic myeloid leukemia in chronic phase (CML-CP). Here, patients' long-term outcomes in ENESTnd are evaluated after a minimum follow-up of 5 years. By 5 years, more than half of all patients in each nilotinib arm (300 mg twice daily, 54%; 400 mg twice daily, 52%) achieved a molecular response 4.5 (MR(4.5); BCR-ABL⩽0.0032% on the International Scale) compared with 31% of patients in the imatinib arm. A benefit of nilotinib was observed across all Sokal risk groups. Overall, safety results remained consistent with those from previous reports. Numerically more cardiovascular events (CVEs) occurred in patients receiving nilotinib vs imatinib, and elevations in blood cholesterol and glucose levels were also more frequent with nilotinib. In contrast to the high mortality rate associated with CML progression, few deaths in any arm were associated with CVEs, infections or pulmonary diseases. These long-term results support the positive benefit-risk profile of frontline nilotinib 300 mg twice daily in patients with CML-CP.

European LeukemiaNet recommendations for the management and avoidance of adverse events of treatment in chronic myeloid leukaemia.

Most reports on chronic myeloid leukaemia (CML) treatment with tyrosine kinase inhibitors (TKIs) focus on efficacy, particularly on molecular response and outcome. In contrast, adverse events (AEs) are often reported as infrequent, minor, tolerable and manageable, but they are increasingly important as therapy is potentially lifelong and multiple TKIs are available. For this reason, the European LeukemiaNet panel for CML management recommendations presents an exhaustive and critical summary of AEs emerging during CML treatment, to assist their understanding, management and prevention. There are five major conclusions. First, the main purpose of CML treatment is the antileukemic effect. Suboptimal management of AEs must not compromise this first objective. Second, most patients will have AEs, usually early, mostly mild to moderate, and which will resolve spontaneously or are easily controlled by simple means. Third, reduction or interruption of treatment must only be done if optimal management of the AE cannot be accomplished in other ways, and frequent monitoring is needed to detect resolution of the AE as early as possible. Fourth, attention must be given to comorbidities and drug interactions, and to new events unrelated to TKIs that are inevitable during such a prolonged treatment. Fifth, some TKI-related AEs have emerged which were not predicted or detected in earlier studies, maybe because of suboptimal attention to or absence from the preclinical data. Overall, imatinib has demonstrated a good long-term safety profile, though recent findings suggest underestimation of symptom severity by physicians. Second and third generation TKIs have shown higher response rates, but have been associated with unexpected problems, some of which could be irreversible. We hope these recommendations will help to minimise adverse events, and we believe that an optimal management of them will be rewarded by better TKI compliance and thus better CML outcomes, together with better quality of life.

Frontline nilotinib in patients with chronic myeloid leukemia in chronic phase: results from the European ENEST1st study.

The Evaluating Nilotinib Efficacy and Safety in Clinical Trials as First-Line Treatment (ENEST1st) study included 1089 patients with newly diagnosed chronic myeloid leukemia in chronic phase. The rate of deep molecular response (MR(4) (BCR-ABL1⩽0.01% on the International Scale or undetectable BCR-ABL1 with ⩾10,000 ABL1 transcripts)) at 18 months was evaluated as the primary end point, with molecular responses monitored by the European Treatment and Outcome Study network of standardized laboratories. This analysis was conducted after all patients had completed 24 months of study treatment (80.9% of patients) or discontinued early. In patients with typical BCR-ABL1 transcripts and ⩽3 months of prior imatinib therapy, 38.4% (404/1052) achieved MR(4) at 18 months. Six patients (0.6%) developed accelerated or blastic phase, and 13 (1.2%) died. The safety profile of nilotinib was consistent with that of previous studies, although the frequencies of some nilotinib-associated adverse events were lower (for example, rash, 21.4%). Ischemic cardiovascular events occurred in 6.0% of patients. Routine monitoring of lipid and glucose levels was not mandated in the protocol. These results support the use of frontline nilotinib, particularly when achievement of a deep molecular response (a prerequisite for attempting treatment-free remission in clinical trials) is a treatment goal.

Survival after reduced-intensity conditioning is not inferior to standard high-dose conditioning before allogeneic haematopoietic cell transplantation in acute leukaemias.

To assess the role of allogeneic stem cell transplantation (SCT) after reduced-intensity conditioning (RIC) in acute leukaemias, we retrospectively compared 25 patients with acute lymphoblastic leukaemia or acute myelogenous leukaemia after RIC to a historical group of 50 matched controls after high-dose conditioning. Engraftment, acute GvHD and severe infections were comparable in both groups. During the observation period, 1/25 patients (4%) after RIC and 14/50 (28%) after standard SCT died due to transplant-related causes; cumulative nonrelapse mortality (NRM) was 4% after RIC and 24% after standard SCT (P=0.029). In total, 15/25 patients (60%) relapsed after RIC and 20/50 (40%) after standard SCT; probability of disease-free survival (DFS) at 3 years was 43% after RIC and 49% after standard SCT (NS). Overall survival (OS) was 40% after RIC and 37% after standard SCT (NS). Stage of disease, cytogenetic risk profile, acute and chronic GvHD, chimerism status at day 90 and severe infections after transplantation were risk factors with significant impact on DFS and/or OS. In retrospective analysis, patients with acute leukaemias who receive RIC because of contraindications against standard SCT have a comparable outcome to standard SCT, but the higher relapse rate warrants further studies.

Dynamics of BCR-ABL mRNA expression in first-line therapy of chronic myelogenous leukemia patients with imatinib or interferon alpha/ara-C.

We sought to determine dynamics of BCR-ABL mRNA expression levels in 139 patients with chronic myelogenous leukemia (CML) in early chronic phase, randomized to receive imatinib (n=69) or interferon (IFN)/Ara-C (n=70). The response was sequentially monitored by cytogenetics from bone marrow metaphases (n=803) and qualitative and quantitative RT-PCR from peripheral blood samples (n=1117). Complete cytogenetic response (CCR) was achieved in 60 (imatinib, 87%) vs 10 patients (IFN/Ara-C, 14%) after a median observation time of 24 months. Within the first year after CCR, best median ratio BCR-ABL/ABL was 0.087%, (imatinib, n=48) vs 0.27% (IFN/Ara-C, n=9, P=0.025). BCR-ABL was undetectable in 25 cases by real-time PCR, but in only four patients by nested PCR. Median best response in patients with relapse after CCR was 0.24% (n=3) as compared to 0.029% in patients with continuous remission (n=52, P=0.029). We conclude that (i) treatment with imatinib in newly diagnosed CML patients is associated with a rapid decrease of BCR-ABL transcript levels; (ii) nested PCR may reveal residual BCR-ABL transcripts in samples that are negative by real-time PCR; (iii) BCR-ABL transcript levels parallel cytogenetic response, and (iv) imatinib is superior to IFN/Ara-C in terms of the speed and degree of molecular responses, but residual disease is rarely eliminated.

Liquid chromatographic method for detection and quantitation of STI-571 and its main metabolite N-desmethyl-STI in plasma, urine, cerebrospinal fluid, culture medium and cell preparations.

An isocratic online-enrichment HPLC-assay was developed allowing for the simple and fast separation and quantitation of STI-571 and its main metabolite N-desmethyl-STI (N-DesM-STI) in plasma, urine, cerebrospinal fluid (CSF), culture media and cell preparations in various concentrations using UV-detection at 260 nm. The analytical procedure consists of an online concentration of STI-571 and N-DesM-STI in the HPLC system followed by the elution on a ZirChrom-PBD analytical column. Time of analysis is 40 min including the enrichment time of 5 min. The detection limit is 10 ng/ml in plasma, CSF, culture medium (RPMI) and 25 ng/ml in urine for both STI-571 and N-DesM-STI. The intra-day precision, as expressed by the coefficient of variation (CV), in plasma samples ranges between 1.74 and 8.60% for STI-571 and 1.45 and 8.87% for N-DesM-STI. The corresponding values for urine measurements are 2.17-7.54% (STI-571) and 1.31-9.51% (N-DesM-STI). The inter-day precision analyzed over a 7-month time period was 8.31% (STI-571) or 6.88% (N-DesM-STI) and 16.45% (STI-571) or 14.83% (N-DesM-STI) for a concentration of 1000 ng/ml in plasma and 750 ng/ml in urine, respectively. Moreover, we demonstrate that with an alternative, but more time and labor consuming sample preparation and the implementation of electrochemical detection, a detection limit < 10 ng/ml can be achieved. The method described was used to perform pharmacokinetic measurements of STI-571 and N-desmethyl-STI in patient samples and for kinetic measurements of intracellular STI-571 and N-DesM-STI following in vitro incubation.

Rates of peripheral arterial occlusive disease in patients with chronic myeloid leukemia in the chronic phase treated with imatinib, nilotinib, or non-tyrosine kinase therapy: a retrospective cohort analysis.

Peripheral arterial occlusive disease (PAOD) occurs in patients with chronic phase chronic myeloid leukemia (CML-CP) treated with tyrosine kinase inhibitors (TKIs). The risk of developing PAOD on TKI therapy is unknown and causality has not been established. Patients with CML-CP from three randomized phase III studies (IRIS, TOPS and ENESTnd) were divided into three cohorts: no TKI (cohort 1; n=533), nilotinib (cohort 2; n=556) and imatinib (cohort 3; n=1301). Patients with atherosclerotic risk factors were not excluded. Data were queried for terms indicative of PAOD. Overall, 3, 7 and 2 patients in cohorts 1, 2 and 3, respectively, had PAOD; 11/12 patients had baseline PAOD risk factors. Compared with that of cohort 1, exposure-adjusted risks of PAOD for cohorts 2 and 3 were 0.9 (95% CI, 0.2-3.3) and 0.1 (95% CI, 0.0-0.5), respectively. Multivariate logistic regression revealed that nilotinib had no impact on PAOD rates compared with no TKI, whereas imatinib had decreased rates of PAOD compared with no TKI. Nilotinib was associated with higher rates of PAOD versus imatinib. Baseline assessments, preferably within clinical studies, of PAOD and associated risk factors should occur when initiating TKI therapy in CML; patients should receive monitoring and treatment according to the standard of care for these comorbidities.

Peripheral artery occlusive disease in chronic phase chronic myeloid leukemia patients treated with nilotinib or imatinib.

Several retrospective studies have described the clinical manifestation of peripheral artery occlusive disease (PAOD) in patients receiving nilotinib. We thus prospectively screened for PAOD in patients with chronic phase chronic myeloid leukemia (CP CML) being treated with tyrosine kinase inhibitors (TKI), including imatinib and nilotinib. One hundred and fifty-nine consecutive patients were evaluated for clinical and biochemical risk factors for cardiovascular disease. Non-invasive assessment for PAOD included determination of the ankle-brachial index (ABI) and duplex ultrasonography. A second cohort consisted of patients with clinically manifest PAOD recruited from additional collaborating centers. Pathological ABI were significantly more frequent in patients on first-line nilotinib (7 of 27; 26%) and in patients on second-line nilotinib (10 of 28; 35.7%) as compared with patients on first-line imatinib (3 of 48; 6.3%). Clinically manifest PAOD was identified in five patients, all with current or previous nilotinib exposure only. Relative risk for PAOD determined by a pathological ABI in first-line nilotinib-treated patients as compared with first-line imatinib-treated patients was 10.3. PAOD is more frequently observed in patients receiving nilotinib as compared with imatinib. Owing to the severe nature of clinically manifest PAOD, longitudinal non-invasive monitoring and careful assessment of risk factors is warranted.

MK-0457, an Aurora kinase and BCR-ABL inhibitor, is active in patients with BCR-ABL T315I leukemia.

MK-0457, an Aurora kinase and BCR-ABL inhibitor, was studied on a Phase I/II study in 77 patients with refractory hematologic malignancies. The average number of cycles per patient was 3 (range 1-21). Maximum tolerated doses for a 5-day short infusion and continuous infusion regimens were 40 mg/m(2)/h and 144 mg/m(2)/h, respectively. Drug-related adverse events (AEs) included transient mucositis and alopecia. Eight of 18 patients with BCR-ABL T315I-mutated chronic myelogenous leukemia (44%) had hematologic responses and one of three patients (33%) with Philadelphia chromosome-positive acute lymphoblastic leukemia obtained complete remission. MK-0457 has important activity in patients with leukemias expressing the highly resistant T315I BCR-ABL mutation.

Nilotinib in imatinib-resistant or imatinib-intolerant patients with chronic myeloid leukemia in chronic phase: 48-month follow-up results of a phase II study.

Nilotinib (Tasigna) is a BCR-ABL1 tyrosine kinase inhibitor approved for the treatment of patients with Philadelphia chromosome-positive chronic myeloid leukemia in chronic phase (CML-CP) who are newly diagnosed or intolerant of or resistant to imatinib. The 48-month follow-up data for patients with CML-CP treated with nilotinib after imatinib resistance or intolerance on an international phase II study were analyzed. Overall, 59% of patients achieved major cytogenetic response; 45% achieved complete cytogenetic response while on study. The estimated rate of overall survival (OS) and progression-free survival (PFS) at 48 months was 78% and 57%, respectively. Deeper levels of molecular responses at 3 and 6 months were highly positively correlated with long-term outcomes, including PFS and OS at 48 months. Of the 321 patients initially enrolled in the study, 98 (31%) were treated for at least 48 months. Discontinuations were primarily due to disease progression (30%) or adverse events (21%). Nilotinib is safe and effective for long-term use in responding patients with CML-CP who are intolerant of or resistant to imatinib. Further significant improvements in therapy are required for patients who are resistant or intolerant to imatinib.

Prediction of outcomes in patients with Ph+ chronic myeloid leukemia in chronic phase treated with nilotinib after imatinib resistance/intolerance.

The purpose was to assess predictive factors for outcome in patients with chronic myeloid leukemia (CML) in chronic phase (CML-CP) treated with nilotinib after imatinib failure. Imatinib-resistant and -intolerant patients with CML-CP (n=321) were treated with nilotinib 400 mg twice daily. Of 19 baseline patient and disease characteristics and two response end points analyzed, 10 independent prognostic factors were associated with progression-free survival (PFS). In the multivariate analysis, major cytogenetic response (MCyR) within 12 months, baseline hemoglobin ≥ 120 g/l, baseline basophils <4%, and absence of baseline mutations with low sensitivity to nilotinib were associated with PFS. A prognostic score was created to stratify patients into five groups (best group: 0 of 3 unfavorable risk factors and MCyR by 12 months; worst group: 3 of 3 unfavorable risk factors and no MCyR by 12 months). Estimated 24-month PFS rates were 90%, 79%, 67% and 37% for patients with prognostic scores of 0, 1, 2 and 3, respectively, (no patients with score of 4). Even in the presence of poor disease characteristics, nilotinib provided significant clinical benefit in patients with imatinib-resistant or -intolerant CML. This system may yield insight on the prognosis of patients.