Imatinib 800 mg daily induces deeper molecular responses than imatinib 400 mg daily: results of SWOG S0325, an intergroup randomized PHASE II trial in newly diagnosed chronic phase chronic myeloid leukaemia

The standard dose of imatinib for newly diagnosed patients with chronic phase chronic myeloid leukaemia (CP-CML) is 400 mg daily (IM400), but the optimal dose is unknown. This randomized phase II study compared the rates of molecular, haematological and cytogenetic response to IM400 vs. imatinib 400 mg twice daily (IM800) in 153 adult patients with CP-CML. Dose adjustments for toxicity were flexible to maximize retention on study. Molecular response (MR) at 12 months was deeper in the IM800 arm (4-log reduction of BCR-ABL1 mRNA: 25% vs. 10% of patients, P = 0·038; 3-log reduction: 53% vs. 35%, P = 0·049). During the first 12 months BCR-ABL1 levels in the IM800 arm were an average 2·9-fold lower than in the IM400 arm (P = 0·010). Complete haematological response was similar, but complete cytogenetic response was higher with IM800 (85% vs. 67%, P = 0·040). Grade 3-4 toxicities were more common for IM800 (58% vs. 31%, P = 0·0007), and were most commonly haematological. Few patients have relapsed, progressed or died, but both progression-free (P = 0·048) and relapse-free (P = 0·031) survival were superior for IM800. In newly diagnosed CP-CML patients, IM800 induced deeper MRs than IM400, with a trend for improved progression-free and overall survival, but was associated with more severe toxicity.

Abstract C225: IL1RAP as functionally relevant target for stem-cell directed therapy in acute myeloid leukemia (AML) and myelodysplastic syndromes (MDS)

Despite the established use of poly-chemotherapy, relapse continues to be the most common cause of death in AML and MDS and cure rates remain below 20%. AML/MDS arise following the accumulation of stepwise genetic and epigenetic changes in hematopoietic stem and progenitor cells (HSPC).

Utilizing a novel strategy of parallel transcriptional analysis of sorted HSPC populations in distinct subtypes of AML, we compared the gene expression in AML HSPC with identical compartments from age-matched healthy controls and identified Interleukin 1 receptor accessory protein (IL1RAP) as one of the most significantly upregulated genes in HSPC in all examined subtypes of AML. Fluorescence in situ hybridization of sorted IL1RAP+ and IL1RAP- cells from patients with monosomy 7 AML (-7) indicated that the aberrant clone was restricted to IL1RAP+ cells, demonstrating that IL1RAP overexpression is a distinguishing feature of the -7 clone. Multivariate analysis of a large cohort of patients with normal karyotype AML showed that patients with high IL1RAP levels had inferior overall survival than patients with lower IL1RAP levels, suggesting an independent prognostic value for this molecule in AML. IL1RAP expression levels in MDS were found elevated on stem cells of patients with high risk disease, proposing a role of IL1RAP in higher risk MDS and progression to AML.

Downregulation of IL1RAP expression by lentivirally expressed shRNAs decreased clonogenicity in cell lines and AML/MDS primary patient samples, induced apoptosis of AML cells, and reduced proliferation of AML cells and infiltration of hematopoietic organs in vivo. IL1RAP is a transmembrane protein required for signaling through several receptors of the IL1 family. Downregulation of IL1RAP expression in AML cells led to phosphorylation changes in several kinases and their substrates suggesting participation of IL1RAP in multiple signaling pathways and highlighting its potential as therapeutic target.

We investigated whether inhibition of IL1RAP with pharmacological compounds is feasible and effective. Antibody-mediated inhibition of IL1RAP led to inhibition of AML cell growth in vitro. In addition, we designed peptides to interfere with IL1RAP-receptor interactions which lead to inhibition of AML cell growth. Both types of agents are being further tested and optimized.

In summary, our study reveals IL1RAP as aberrantly expressed on HSPC of AML and high-risk MDS patients. Inhibition of IL1RAP is feasible and functionally effective, and thus has the potential to lead to novel therapies specifically directed at such stem cells.

Beyond IL1RAP, our study provides a map of dysregulated transcripts in HSPC from patients with AML, which may offer further opportunities for therapeutic intervention. The strategy of comparative analysis of sorted stem and progenitor cells in cancer versus healthy controls may be applicable to other type of cancers with a suspected stem cell origin, and instrumental for the identification of targets for stem cell-directed therapy.

Citation Information: Mol Cancer Ther 2013;12(11 Suppl):C225.

Citation Format: Laura Barreyro, Kelly Mitchell, Britta Will, Boris Bartholdy, Li Zhou, Tihomira Todorova, Robert Stanley, Susana Ben-Neriah, Cristina Montagna, Samir Parekh, Andrea Pellagatti, Jacqueline Boultwood, Elisabeth Paietta, Rhett Ketterling, Larry Cripe, Hugo Fernandez, Peter Greenberg, Jacob Rowe, Martin Tallman, Christian Steidl, Constantine Mitsiades, Amit Verma, Ulrich Steidl. IL1RAP as functionally relevant target for stem-cell directed therapy in acute myeloid leukemia (AML) and myelodysplastic syndromes (MDS). [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2013 Oct 19-23; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2013;12(11 Suppl):Abstract nr C225.

Proposed criteria for response assessment in patients treated in clinical trials for myeloproliferative neoplasms in blast phase (MPN-BP): formal recommendations from the post-myeloproliferative neoplasm acute myeloid leukemia consortium

Leukemic transformation (LT) of a myeloproliferative neoplasm (MPN) is associated with a dismal prognosis and no medical therapies have shown a survival improvement in patients with MPN in blast phase (MPN-BP). Effective therapies for the treatment of MPN-BP are a serious unmet need. Consensus response criteria do not exist for the treatment of patients with MPN-BP and this is necessary for the uniformed reporting of treatment response in clinical trials. We have identified relevant MPN and MPN-BP features in order to define treatment response categories that reflect hematological, clinical, pathological, cytogenetic and molecular changes after therapeutic intervention. We plan to validate these proposed response criteria within multi-centered clinical trials.

IGH@ translocations, CRLF2 deregulation, and microdeletions in adolescents and adults with acute lymphoblastic leukemia

PURPOSE

To determine the prevalence and prognostic impact of significant acute lymphoblastic leukemia (ALL) -related genes: CRLF2 deregulation (CRLF2-d), IGH@ translocations (IGH@-t), and deletions of CDKN2A/B, IKZF1, PAX5, ETV6, RB1, BTG1, and EBF1 in adolescents and adults.

PATIENTS AND METHODS

The cohort comprised 454 patients (age 15 to 60 years old) treated on the multicenter United Kingdom Acute Lymphoblastic Leukaemia Trial XII/Eastern Cooperative Oncology Group 2993 trial (UKALLXII/ECOG2993) with Philadelphia-negative B-cell precursor ALL. Fluorescent in situ hybridization and multiplex ligation-dependent probe amplification were used to detect these genetic alterations.

RESULTS

Twenty patients (5%) had CRLF2-d (P2RY8-CRLF2, n = 7; IGH@-CRLF2, n = 13), and 36 patients (8%) harbored an IGH@-t with a different partner gene. There was little overlap between IGH@-t, CRLF2-d, and established chromosomal abnormalities. Deletions of CDKN2A/B, IKZF1, PAX5, ETV6, RB1, BTG1, or EBF1 were prevalent with 101 (33%) of 304 patients harboring one and 102 (33%) harboring two or more alterations, occurring with varying frequency in all cytogenetic subgroups. The 5-year event-free survival, relapse-free survival (RFS), and overall survival (OS) rates for the whole cohort were 40%, 55%, and 43%, respectively. Patients with CRLF2-d, IGH@-t, and IKZF1 deletions were associated with an inferior outcome in univariate but not multivariate analysis. In particular, CRLF2-d patients had a lower RFS compared with other patients (30%), whereas those with IGH@-t or IKZF1 deletions had a lower OS (27% and 35%, respectively).

CONCLUSION

CRLF2-d and IGH@-t represent distinct subtypes of adolescent and adult ALL. Deletions of key B-cell differentiation and cell cycle control genes are highly prevalent but vary in frequency by cytogenetic subgroup. CRLF2-d, IGH@-t, and IKZF1 deletions are associated with poor outcome in adolescent and adult ALL.

Optimizing the CD34 + cell dose for reduced-intensity allogeneic hematopoietic stem cell transplantation

Low CD34 + cell doses increase allograft-related mortality and very high doses increase the risk of graft-versus-host disease. The optimum CD34 + cell dose remains undefined. The effect of the CD34 + cell dose based on ideal weight was analyzed in 130 patients with hematologic malignancies undergoing reduced-intensity allogeneic blood cell transplantation in the context of factors known to affect the outcome: chemosensitivity, donor age, lactate dehydrogenase (LDH), human leukocyte antigen (HLA) match, performance status, and platelet count. The survival of patients receiving >8 x 10(6)/kg CD34 + cells was not significantly different from those receiving <6. The outcome of those receiving 6-8 x 10(6)/kg CD34 + cells was significantly better than the rest. This superiority was confirmed in multivariable analysis. Among patients receiving <or=8 x 10(6)/kg CD34 + cells, an increasing number of infused cells was associated with higher overall survival in a continuous fashion (Risk ratio (RR) 0.8759; p = 0.045). Cell dose based on actual weight did not correlate with survival. The number of CD34 + cells infused, a potentially modifiable factor, affects survival after reduced-intensity allogeneic transplantation. We recommend a CD34 + cell dose of 6-8 x 10(6) per kg ideal body weight to optimize outcome. The possible adverse effect of higher cell doses (>8) needs further confirmation.

Treatment of patients with acute promyelocytic leukemia: a consensus statement on risk-adapted approaches to therapy

The integration of all-trans-retinoic acid (ATRA) with anthracycline chemotherapy into up-front regimens for acute promyelocytic leukemia (APL) has produced striking improvements in clinical outcomes, making APL one of the most curable forms of hematologic malignancies in adults. In addition, arsenic trioxide has proven efficacy in relapse and when combined with ATRA in frontline regimens has demonstrated high efficacy in a number of trials and the potential to replace chemotherapy, which would thereby reduce chemotherapy-related adverse events. Cure in APL is also largely dependent on timely and effective supportive care measures that counteract such life-threatening emergencies as coagulopathy and APL differentiation syndrome. The risk of mortality during induction and the risk of relapse following frontline therapy are related to the individual's initial clinical presentation and relapse-risk score at diagnosis; however, these risks are now quite low even in high-risk patients as long as appropriate therapy is initiated expeditiously. Multiple European and North American trials have investigated risk-adapted approaches to the treatment of APL and have reported high success rates. Further refinement of risk-adapted strategies is ongoing and will likely contribute to better patient care. A roundtable conference was conducted to discuss risk-adapted therapy for APL and to develop a consensus statement and approach for clinical oncologists. Expert opinions and evidence-based strategies presented during the roundtable are summarized herein.

Treatment of children with acute promyelocytic leukemia: results of the first North American Intergroup trial INT0129

BACKGROUND

This report focuses on the children enrolled on the first North American Intergroup study of APL (INT0129). This study was designed to compare the rates of CR, disease-free survival (DFS), overall survival (OS) and toxicity of therapy with all-trans-retinoic acid (ATRA) for remission induction and/or maintenance compared to conventional chemotherapy in patients with previously untreated APL.

PROCEDURE

Fifty-three patients who were documented to have the t(15;17) translocation were able to be evaluated for toxicity of treatment, outcome of induction, and survival.

RESULTS

The overall CR rate was 81%. The estimated 5-year DFS from time of CR was 41% for all patients. The estimated 5-year OS for all patients from entry into the study was 69%. The 5-year DFS from time of CR for patients who were randomized to ATRA for induction or maintenance or both was 48% compared to 0% for patients who never received ATRA (P < 0.0001).

CONCLUSIONS

The most important finding of our study is that a significant DFS advantage exists for children with APL who received ATRA during induction or maintenance or both compared to children who received no ATRA. Furthermore, remissions in these children appear durable as the OS rates are stable at 10 years.

Clinical, pharmacokinetic (PK), and pharmacodynamic findings from a phase I trial of an Eg5 inhibitor (AZD4877) in patients with refractory acute myeloid leukemia (AML)

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Background: AZD4877 is a potent, specific inhibitor of Eg5 (kinesin spindle protein). The only known function of Eg5 is to separate the centromeres during mitosis. Eg5 inhibition is thus specific for dividing cells, resulting in monoastral mitotic spindles (monoasters) and apoptotic cell death. Preclinically, hematologic tumor cell lines were generally more sensitive to AZD4877 than those derived from solid tumors. Methods: AZD4877 was administered IV daily x 3 as induction for up to 2 cycles, followed by consolidation (daily x 2) for up to 4 cycles. Eligibility criteria were standard. Results: Cohorts of 3–6 patients (pts) were treated at doses of 2, 4, 7, 10, 13, 16, and 18 mg/day. To date, 24 evaluable pts have received 33 induction and 3 consolidation cycles of treatment. Monoasters were detected at all dose levels evaluated (2, 7, 10, 13, and 18 mg/day). The T1/2 of AZD4877 ranged from 26 to 42 hr; PK were linear and drug levels non-cumulative. Myelosuppression, the dose limiting toxicity (DLT) in solid tumor studies, was not considered a DLT in this trial. Mucositis was the DLT at 18 mg/day; with 1 pt developing Gr 3 palmar-plantar syndrome at this dose. Bone marrow biopsies were undertaken at screening and as clinically indicated. In pts with evaluable biopsies, marrow blasts decreased by 60–80% in 2 pts, and by 30–50% in 3 pts, with no response in 3 pts. Conclusions: Enrollment is ongoing at 16 mg, the likely Phase 2 dose. Preliminary results suggest possible clinical activity in AML. An expansion phase at the MTD is planned.

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Breakthrough fungal infections after allogeneic hematopoietic stem cell transplantation in patients on prophylactic voriconazole

Seventy-one allograft recipients receiving voriconazole, in whom complete clinical, microbiologic and pharmacokinetic data were available, were studied to determine the efficacy of voriconazole in preventing fungal infections. The length of voriconazole therapy was 6-956 days (median 133). The total number of patient-days on voriconazole was 13 805 ( approximately 38 years). A total of 10 fungal infections were seen in patients on voriconazole (18% actuarial probability at 1 year): Candida glabrata (n=5), Candida krusei (n=1), Cunninghamella (n=1), Rhizopus (n=2) and Mucor (n=1). Two of the four zygomycosis cases were preceded by short durations of voriconazole therapy, but prolonged itraconazole prophylaxis. The plasma steady-state trough voriconazole levels around the time the infection occurred were <0.2, <0.2, 0.33, 0.55, 0.63 and 1.78 microg/ml in the six candidiasis cases. Excluding the four zygomycosis cases, all the six candidiasis cases were seen among the 43 patients with voriconazole levels of < or =2 microg/ml and none among the 24 with levels of >2 microg/ml (P=0.061). We conclude that voriconazole is effective at preventing aspergillosis. However, breakthrough zygomycosis is seen in a small proportion of patients. The role of therapeutic voriconazole monitoring with dose adjustment to avoid breakthrough infections with fungi that are otherwise susceptible to the drug needs to be explored prospectively.

Monitoring plasma voriconazole levels may be necessary to avoid subtherapeutic levels in hematopoietic stem cell transplant recipients

BACKGROUND

Low voriconazole levels have been associated with a higher failure rate in patients with confirmed fungal infections.

METHODS

Steady-state plasma trough voriconazole levels were measured after at least 5 days of therapy in 87 patients with hematologic malignancies on 201 separate occasions (1-5 levels per patient; median, 2). Most patients (90%) had undergone allogeneic hematopoietic stem cell transplantation. The daily voriconazole dose, administered in 2 divided doses, was 200 mg (n = 4), 400 mg (n = 151), 500 mg (n = 20), 600 mg (n = 18), and 800 mg (n = 8); corresponding to 2.0-16.3 (median, 5.4) mg/kg. Plasma voriconazole levels were 0-12.5 microg/mL (median, 1.2). Voriconazole was undetectable (<0.2 mug/mL) in 15%.

RESULTS

The correlation between dose and levels was weak (r = 0.14; P = .045). The median absolute daily drug dose (400 mg) was identical in groups of patients with levels of 0, 0.2 to 0.5, >0.5 to 2.0, >2.0 to 5.0, and >5.0. Whereas the daily drug dose in mg/kg was significantly higher when the levels were >5.0 microg/mL, there was no consistent relation between dose and level below that threshold. In adult patients getting standard doses of voriconazole orally, the drug levels are highly variable. Based on limited available data, between a quarter and two-thirds of these levels could potentially be associated with a lower likelihood of response or a higher likelihood of failure.

CONCLUSIONS

Future voriconazole studies should incorporate prospective therapeutic drug monitoring and consideration should be given to checking levels in patients receiving the drug for confirmed, life-threatening fungal infections.

Reduced-dose rasburicase (recombinant xanthine oxidase) in adult cancer patients with hyperuricemia

Recombinant urate oxidase (rasburicase) lowers uric acid levels rapidly to very low levels at the labeled dose of 0.15-0.2 mg/kg daily for 5 days. Our past experience showed that a lower dose (3 mg) lowered uric acid levels sufficiently in most patients. A retrospective review was conducted to determine the effect of a fixed 3 mg dose of rasburicase in 43 adult patients with cancer undergoing hematopoietic stem cell transplantation or receiving chemotherapy who had elevated or rising uric acid levels (6.4-16.8 mg/dl; median 9.6). Six patients received a second dose of rasburicase (3 mg in four patients and 1.5 mg in two patients) 24 h later. Patients received allopurinol, adequate hydration, as well as other supportive therapy as required. Uric acid levels declined by 6-95% (median 43%) within the first 24 h after rasburicase administration, and levels at 48 h were 9-91% (median 65%) lower than the baseline levels. Serum creatinine changed by < or =10% in 21 patients, increased by >10% in four patients and decreased by >10% in 18 patients. No significant renal dysfunction developed in any of the patients. We conclude that rasburicase is effective in lowering uric acid levels at a fixed dose of 3 mg, which is much lower than the recommended dose.