Volasertib as a monotherapy or in combination with azacitidine in patients with myelodysplastic syndrome, chronic myelomonocytic leukemia, or acute myeloid leukemia: summary of three phase I studies.

BACKGROUND: This report summarizes three phase I studies evaluating volasertib, a polo-like kinase inhibitor, plus azacitidine in adults with myelodysplastic syndromes (MDS), chronic myelomonocytic leukemia, or acute myeloid leukemia. METHODS: Patients received intravenous volasertib in 28-day cycles (dose-escalation schedules). In Part 1 of 1230.33 (Study 1; NCT01957644), patients received 250-350 mg volasertib on day (D)1 and D15; in Part 2, patients received different schedules [A, D1: 170 mg/m2; B, D7: 170 mg/m2; C, D1 and D7: 110 mg/m2]. In 1230.35 (Study 2; NCT02201329), patients received 200-300 mg volasertib on D1 and D15. In 1230.43 (Study 3; NCT02721875), patients received 110 mg/m2 volasertib on D1 and D8. All patients in Studies 1 and 2, and approximately half of the patients in Study 3, were scheduled to receive subcutaneous azacitidine 75 mg/m2 on D1-7. RESULTS: Overall, 22 patients were treated (17 with MDS; 12 previously untreated). Across Studies 1 and 2 (n = 21), the most common drug-related adverse events were hematological (thrombocytopenia [n = 11]; neutropenia [n = 8]). All dose-limiting toxicities were grade 4 thrombocytopenia. The only treated patient in Study 3 experienced 18 adverse events following volasertib monotherapy. Studies 1 and 2 showed preliminary activity (objective response rates: 25 and 40%). CONCLUSIONS: The safety of volasertib with azacitidine in patients with MDS was consistent with other volasertib studies. All studies were terminated prematurely following the discontinuation of volasertib for non-clinical reasons by Boehringer Ingelheim; however, safety information on volasertib plus azacitidine are of interest for future studies in other diseases.

Adjunctive Volasertib in Patients With Acute Myeloid Leukemia not Eligible for Standard Induction Therapy: A Randomized, Phase 3 Trial.

In this phase 3 trial, older patients with acute myeloid leukemia ineligible for intensive chemotherapy were randomized 2:1 to receive the polo-like kinase inhibitor, volasertib (V; 350 mg intravenous on days 1 and 15 in 4-wk cycles), combined with low-dose cytarabine (LDAC; 20 mg subcutaneous, twice daily, days 1-10; n = 444), or LDAC plus placebo (P; n = 222). Primary endpoint was objective response rate (ORR); key secondary endpoint was overall survival (OS). Primary ORR analysis at recruitment completion included patients randomized ≥5 months beforehand; ORR was 25.2% for V+LDAC and 16.8% for P+LDAC (n = 371; odds ratio 1.66 [95% confidence interval (CI), 0.95-2.89]; P = 0.071). At final analysis (≥574 OS events), median OS was 5.6 months for V+LDAC and 6.5 months for P+LDAC (n = 666; hazard ratio 0.97 [95% CI, 0.8-1.2]; P = 0.757). The most common adverse events (AEs) were infections/infestations (grouped term; V+LDAC, 81.3%; P+LDAC, 63.5%) and febrile neutropenia (V+LDAC, 60.4%; P+LDAC, 29.3%). Fatal AEs occurred in 31.2% with V+LDAC versus 18.0% with P+LDAC, most commonly infections/infestations (V+LDAC, 17.1%; P+LDAC, 6.3%). Lack of OS benefit with V+LDAC versus P+LDAC may reflect increased early mortality with V+LDAC from myelosuppression and infections.

Phase 1 dose escalation trial of volasertib in combination with decitabine in patients with acute myeloid leukemia.

Polo-like kinase 1 (PLK1) regulates mitotic checkpoints and cell division. PLK1 overexpression is reported in numerous cancers, including acute myeloid leukemia (AML), and is associated with poor prognosis. Volasertib is a selective, potent cell-cycle kinase inhibitor that targets PLK to induce mitotic arrest and apoptosis. This phase 1 trial investigated the maximum tolerated dose (MTD), safety, pharmacokinetics, and anti-leukemic activity of volasertib in combination with decitabine in AML patients aged ≥ 65 years. Thirteen patients were treated with escalating volasertib doses (3 + 3 design; 300 mg, 350 mg, and 400 mg) plus standard-dose decitabine. Dose-limiting toxicity was reported in one patient in cycle 1; the MTD of volasertib in combination with decitabine was determined as 400 mg. The most common treatment-emergent adverse events were febrile neutropenia, pneumonia, and decreased appetite. Objective response rate was 23%. The combination was well tolerated, and the adverse event profile was in line with previous findings.

Potential Drug-Drug Interactions with Combination Volasertib + Itraconazole: A Phase I, Fixed-sequence Study in Patients with Solid Tumors.

PURPOSE: This drug-drug interaction study determined whether the metabolism and distribution of the Polo-like kinase 1 inhibitor, volasertib, is affected by co-administration of the P-glycoprotein and cytochrome P-450 3A4 inhibitor, itraconazole. METHODS: This was an uncontrolled, open-label, fixed-sequence trial of two 21-day treatment cycles in patients with various solid tumors. In cycle 1 (test), eligible patients were administered volasertib (day 1) plus itraconazole (days -3 to 15). In cycle 2 (reference), patients received volasertib monotherapy. The primary end point was the influence of co-administration of itraconazole on the pharmacokinetic profile (AUC0-tz; Cmax) of volasertib and its main metabolite, CD 10899, compared with that of volasertib monotherapy. Other end points included tolerability and preliminary therapeutic efficacy. FINDINGS: Concurrent administration of itraconazole resulted in a slight reduction in the AUC0-tz (geometric mean ratio, 93.6%; 90% CI, 82.1%-106.8%) and a 20% reduction in Cmax (geometric mean ratio, 79.4%; 90% CI, 64.9%-97.1%) of volasertib compared with monotherapy. Of note, concurrent administration of itraconazole + volasertib had no effect on the AUC0-∞ of volasertib. More patients reported at least one drug-related adverse event in cycle 1 than in cycle 2 (75% vs 71%). The most commonly reported drug-related adverse events (cycles 1 and 2) were thrombocytopenia (68% and 33%, respectively), leukopenia (50% and 46%), and anemia (36% and 33%). No objective responses were observed. Stable disease was observed in 25 of 28 patients (89%). IMPLICATIONS: While there was no clear evidence of a pharmacokinetic interaction between volasertib and itraconazole, co-administration reduced the tolerability of volasertib. Clinicaltrials.gov identifier: NCT01772563.

Phase I dose-escalation study of volasertib in pediatric patients with acute leukemia or advanced solid tumors.

BACKGROUND: Volasertib induces mitotic arrest and apoptosis by targeting Polo-like kinases. In this phase I dose-escalation study, the maximum tolerated dose (MTD), pharmacokinetics (PK), and preliminary efficacy of volasertib were determined in pediatric patients. METHODS: Patients aged 2 to <18 years with relapsed/refractory acute leukemia/advanced solid tumors (ST) without available effective treatments were enrolled-cohort C1 (aged 2 to <12 years); cohort C2 (aged 12 to <18 years). The patients received volasertib intravenously (starting dose: 200 mg/m2 body surface area on day 1, every 14 days). The primary endpoint was the pediatric MTD for further development. RESULTS: Twenty-two patients received treatment (C1: leukemia, n = 4; ST, n = 8; C2: leukemia, n = 3; ST, n = 7). No dose-limiting toxicities (DLTs) occurred up to 300 mg/m2 volasertib in C1; two patients in C2, at 250 mg/m2 volasertib, had DLTs in cycle 1, one of which led to death; therefore, the MTD of volasertib in C2 was 200 mg/m2 . The most common grade 3/4 adverse events (all patients) were febrile neutropenia, thrombocytopenia, and neutropenia (41% each). Stable disease (SD) was the best objective response (leukemia, n = 5; ST, n = 2); the duration of SD was short in all patients, except in one with an ST. PK profiles were generally comparable across dose groups and were consistent with those in adults. CONCLUSION: The pediatric MTD/dose for further development was identified. There were no unexpected safety or PK findings; limited antitumor/antileukemic activity was demonstrated.

Strategic and Statistical Considerations on the QT Assessment of Volasertib.

Volasertib is a selective cell cycle kinase inhibitor that induces mitotic arrest and apoptosis by targeting Polo-like kinase (Plk). A potential for prolonged QT intervals was indicated with volasertib in preclinical studies and preliminary clinical data. As a result, electrocardiograms (ECGs) have been collected in all volasertib clinical trials to monitor potential cardiac effects. This article describes strategic and statistical methods prospectively planned to perform an integrated analysis of ECG data from available trials to evaluate volasertib's effect on cardiac repolarization, as reflected by changes in the duration of QT interval and other ECG-related endpoints. Methods to effectively cope with heterogeneity between trials (ie, differences in study designs) are discussed. These strategies may be useful for other investigational drugs for which QT risk assessment is required, but a thorough QT/QTc trial is not feasible, resulting in the need for an alternative approach. Volasertib therapy relevantly prolonged adjusted mean QTcF change from administration baseline following the first and subsequent infusions. The integrated analysis revealed that the volasertib effects on the mean QTc changes from baseline were transient and had resolved at 24 hours after start of the first infusion. There was no evidence for a long-term impact on the QTcF interval following multiple infusions with volasertib.

Phase I trial of volasertib, a Polo-like kinase inhibitor, in Japanese patients with advanced solid tumors.

PURPOSE: This trial evaluated the maximum tolerated dose (MTD), safety, pharmacokinetics, and clinical effects of volasertib, a selective Polo-like kinase inhibitor that induces mitotic arrest and apoptosis, in Japanese patients with advanced solid tumors (NCT01348347; 1230.15). METHODS: In this phase I, open-label, dose-escalation trial, sequential patient cohorts (3 + 3 dose-escalation design) received volasertib (200-350 mg) as a single dose by intravenous infusion over 2 h on day 1 every 21 days until disease progression or unacceptable toxicity. The primary endpoint was the MTD of volasertib in Japanese patients with an advanced solid tumor; secondary endpoints included safety, pharmacokinetics, and clinical benefit. RESULTS: Fifteen patients with an advanced solid tumor were treated. Dose-limiting toxicities of grade 4 neutropenia for ≥7 days and grade 4 thrombocytopenia were both experienced by 2/6 patients in the 350 mg cohort. The MTD of volasertib in Japanese patients was 300 mg. The most common (≥3 patients) drug-related non-hematologic adverse events included fatigue, decreased appetite, and nausea. Exposure to volasertib and its metabolite increased with increasing doses. A partial response in a patient with gastric cancer and stable disease in eleven patients were observed. CONCLUSIONS: Volasertib had a manageable safety profile up to the MTD determined as 300 mg. Exposure to volasertib and its metabolite increased with increasing doses. The safety profile of volasertib in Japanese patients is comparable with those previously obtained in Caucasian patients. These data support enrollment of Japanese patients in global clinical trials without dose modification.

Phase I trial of volasertib, a Polo-like kinase inhibitor, in Japanese patients with acute myeloid leukemia.

This phase I trial conducted in Japanese patients with acute myeloid leukemia evaluated the safety, maximum tolerated dose and pharmacokinetics of volasertib (BI 6727), a selective Polo-like kinase inhibitor. The primary endpoints were the maximum tolerated dose of volasertib and the incidence of dose-limiting toxicities. Secondary endpoints were best response and remission duration. Other endpoints included safety and pharmacokinetics. Patients who were ineligible for standard induction therapy or with relapsed or refractory disease received volasertib monotherapy as a 2-h infusion on days 1 and 15 of a 28-day cycle, with dose escalation following a 3 + 3 design. A total of 19 patients were treated with three volasertib doses: 350, 400 and 450 mg. One patient receiving volasertib 450 mg reported a dose-limiting toxicity of grade 4 abnormal liver function test and 450 mg was determined as the maximum tolerated dose. The most frequently reported adverse events were febrile neutropenia (78.9%), decreased appetite (42.1%), nausea and rash (36.8% each), and sepsis, fatigue, hypokalemia, stomatitis and epistaxis (26.3% each). Best responses were complete remission (n = 3), complete remission with incomplete blood count recovery (n = 3) and partial remission (n = 1). The median remission duration of the six patients with complete remission or complete remission with incomplete blood count recovery was 85 days (range 56-358). Volasertib exhibited multi-compartmental pharmacokinetic behavior with a fast distribution after the end of infusion followed by slower elimination phases. Volasertib monotherapy was clinically manageable with acceptable adverse events and anti-leukemic activity.

Randomized, phase 2 trial of low-dose cytarabine with or without volasertib in AML patients not suitable for induction therapy.

Treatment outcomes for older patients with acute myeloid leukemia (AML) have remained dismal. This randomized, phase 2 trial in AML patients not considered suitable for intensive induction therapy compared low-dose cytarabine (LDAC) with or without volasertib, a highly potent and selective inhibitor of polo-like kinases. Eighty-seven patients (median age 75 years) received LDAC 20 mg twice daily subcutaneously days 1-10 or LDAC + volasertib 350 mg IV days 1 + 15 every 4 weeks. Response rate (complete remission and complete remission with incomplete blood count recovery) was higher for LDAC + volasertib vs LDAC (31.0% vs 13.3%; odds ratio, 2.91; P = .052). Responses in the LDAC + volasertib arm were observed across all genetic groups, including 5 of 14 patients with adverse cytogenetics. Median event-free survival was significantly prolonged by LDAC + volasertib compared with LDAC (5.6 vs 2.3 months; hazard ratio, 0.57; 95% confidence interval, 0.35-0.92; P = .021); median overall survival was 8.0 vs 5.2 months, respectively (hazard ratio, 0.63; 95% confidence interval, 0.40-1.00; P = .047). LDAC + volasertib led to an increased frequency of adverse events that was most pronounced for neutropenic fever/infections and gastrointestinal events; there was no increase in the death rate at days 60 + 90. This study was registered at www.clinicaltrials.gov as #NCT00804856.

A randomized, open-label, phase I/II trial to investigate the maximum tolerated dose of the Polo-like kinase inhibitor BI 2536 in elderly patients with refractory/relapsed acute myeloid leukaemia.

Polo-like kinases (Plks) play an important role in cell cycle checkpoint controls and are over-expressed in acute myeloid leukaemia (AML). BI 2536, a novel Plk inhibitor, induces mitotic arrest and apoptosis. In this phase I/II trial of BI 2536 in 68 elderly patients with relapsed/refractory AML, three schedules were investigated (day 1, days 1-3, and days 1 + 8). Maximum tolerated dose was 350 and 200 mg in the day 1 and days 1 + 8 schedules, respectively. The day 1-3 schedule appeared equivalent to the day 1 schedule and was discontinued early. BI 2536 exhibited multi-compartmental pharmacokinetic behaviour. The majority of patients showed an increase of bone marrow cells in G2/M with a characteristic pattern of mitotic catastrophe. The overall response rate in the day 1 and day 1 + 8 schedules was 9% (5/54) with 2 complete and 3 partial responses. The majority of drug-related adverse events grade ≥3 were haematological. Taken together, Plk inhibition induced cell cycle arrest in AML blasts in vivo and BI 2536 monotherapy showed modest clinical activity in this poor prognosis patient group.

Outcomes 5 years after response to rituximab therapy in children and adults with immune thrombocytopenia.

Treatments for immune thrombocytopenic purpura (ITP) providing durable platelet responses without continued dosing are limited. Whereas complete responses (CRs) to B-cell depletion in ITP usually last for 1 year in adults, partial responses (PRs) are less durable. Comparable data do not exist for children and 5-year outcomes are unavailable. Patients with ITP treated with rituximab who achieved CRs and PRs (platelets > 150 × 10(9)/L or 50-150 × 10(9)/L, respectively) were selected to be assessed for duration of their response; 72 adults whose response lasted at least 1 year and 66 children with response of any duration were included. Patients had baseline platelet counts < 30 × 10(9)/L; 95% had ITP of > 6 months in duration. Adults and children each had initial overall response rates of 57% and similar 5-year estimates of persisting response (21% and 26%, respectively). Children did not relapse after 2 years from initial treatment whereas adults did. Initial CR and prolonged B-cell depletion predicted sustained responses whereas prior splenectomy, age, sex, and duration of ITP did not. No novel or substantial long-term clinical toxicity was observed. In summary, 21% to 26% of adults and children with chronic ITP treated with standard-dose rituximab maintained a treatment-free response for at least 5 years without major toxicity. These results can inform clinical decision-making.

Interphase FISH on TEL/AML1 positive acute lymphoblastic leukemia relapses--analysis of clinical relevance of additional TEL and AML1 copy number changes.

OBJECTIVES: TEL/AML1 (ETV6/RUNX1) fusion resulting from the translocation t(12;21)(p13;q22) constitutes the most common chimeric fusion gene in initial childhood B-cell precursor (BCP) acute lymphoblastic leukemia (ALL) (19-27%) and has been associated with good prognosis. Three secondary aberrations in TEL/AML1 positive ALL have been suspected to negatively influence outcome: deletion of the second TEL allele (T), gain of the second AML1 allele (A) and duplication of the derivative chromosome 21 (der(21), TA). Many studies have explored such aberrations in initial disease, while only few reports have investigated them in relapses. METHODS: In this study, bone marrow samples from 38 children with relapsed TEL/AML1 RT-PCR positive and negative BCP-ALL were analyzed for these mutations by interphase fluorescence in situ hybridization and results were compared with published data. RESULTS: In children with TEL/AML1 positive ALL relapse, additional (a) TEL loss, (b) combined AML1 and der(21) gain, (c) combined TEL loss and AML1 gain as well as (d) the occurrence of a subpopulation with the signal pattern 1T/3A/1TA appear to be related to higher peripheral blast counts (PBCs) at relapse diagnosis (a and d) or a tendency towards the occurrence of a subsequent relapse (b and c) (P-values <0.05). CONCLUSIONS: Our data together with published results on TEL/AML1 positive ALL suggest that frequencies of additional TEL and AML1 mutations are, with the exception of loss of untranslocated TEL, higher in first relapses than in initial disease. They also show that it is important to consider combined mutations in the analysis of this leukemia entity.

The thalidomide analogue, CC-4047, induces apoptosis signaling and growth arrest in childhood acute lymphoblastic leukemia cells in vitro and in vivo.

PURPOSE: Thalidomide and its analogues have shown promise in the treatment of multiple myeloma but their therapeutic potential has not been evaluated in models of acute lymphoblastic leukemia (ALL). EXPERIMENTAL DESIGN: We assessed the effects of the thalidomide analogue, CC-4047, on the growth and apoptosis signaling of human B cell precursor (BCP) ALL cell lines and freshly obtained childhood BCP-ALL cells grown with or without stromal cells. In addition, we studied the effects of CC-4047 on the progression and dissemination of xenotransplanted human BCP-ALL cells in nonobese diabetic/severe combined immunodeficiency mice. RESULTS: CC-4047 reduced the proliferation of human BCP-ALL cell lines in vitro. In contrast with the antileukemic effect of cytarabin, this was more pronounced when cell lines or freshly obtained childhood BCP-ALL cells were cocultured with stromal cells. CC-4047 induced the cleavage of caspase-3, caspase-9, and poly(ADP-ribose) polymerase in stroma-cocultured BCP-ALL cells. The inhibition of tumor growth, caspase-3 cleavage, and reduced microvessel density was observed in nonobese diabetic/severe combined immunodeficiency mice inoculated s.c. with childhood BCP-ALL cells upon CC-4047 treatment. After i.v. BCP-ALL xenotransplantation, CC-4047 reduced splenic dissemination. CONCLUSIONS: The thalidomide analogue, CC-4047, displays profound cytostatic effects on stroma-supported human ALL cells both in vitro and in vivo.

Brief communication: stability and catalytic activity of novel circular DNAzymes.

UNLABELLED: DNAzymes represent a new generation of catalytic nucleic acids for specific RNA targeting in order to inhibit protein translation from the specifically cleaved mRNA. The 10-23 DNAzyme was found to hydrolyze RNA in a sequence-specific manner both in vitro and in vivo. Although single-stranded DNAzymes may represent the most effective nucleic acid drug to date, they are nevertheless sensitive to nuclease degradation and require modifications for in vivo application. However, previously used stabilization of DNAzymes by site-specific phosphorothioate (PT) modifications reduces the catalytic activity, and the PTO displays toxic side effects when applied in vivo. Thus, improving the stability of DNAzymes without reducing their catalytic activity is essential if the potential of these compounds should be realized in vivo. RESULTS: The Circozyme was tested targeting the mRNA of the most common genetic rearrangement in pediatric acute lymphoblastic leukemia TEL/AML1 (ETV6/RUNX1). The Circozyme exhibits a stability comparable to PTO-modified DNAzymes without reduction of catalytic activity and specificity and may represent a promising tool for DNAzyme in vivo applications. CONCLUSION: The inclusion of the catalytic site and the specific mRNA binding sequence of the DNAzyme into a circular loop-stem-loop structure (Circozyme) of approximately 70 bases presented here represents a new effective possibility of DNAzyme stabilization.

Chemokine IL-8 and chemokine receptor CXCR3 and CXCR4 gene expression in childhood acute lymphoblastic leukemia at first relapse.

In this study, we examined the gene expression of interleukin (IL)-8, CXCR3, and CXCR4 in leukemic cells from 100 children with relapsed B-cell progenitors (BCP) acute lymphoblastic leukemia (ALL), using quantitative real-time polymerase chain reaction (RT-PCR). IL-8, CXCR3, and CXCR4 were expressed in almost all bone marrow (BM) samples. The CXCR4 expression significantly correlated with known prognostic factors at relapse: time point and site of relapse. Patients who had a combined BM relapse (n=21) had lower IL-8 and CXCR4 expression than those who had an isolated BM relapse (n=79). The CXCR3 expression was higher in female patients (n=39) than in male patients (n=61). However, this did not reach prognostic relevance in relapsed ALL.

Expression of interleukin-10 splicing variants is a positive prognostic feature in relapsed childhood acute lymphoblastic leukemia.

PURPOSE: Biologic features of hematologic malignancies have prognostic implications and are essential elements in the design of current therapeutic trials. This study aimed to determine the expression of a splicing-derived variant of interleukin (IL) -10 in leukemic cells and its clinical relevance in children with acute lymphoblastic leukemia (ALL) at first relapse. PATIENTS AND METHODS: Between January 1997 and December 2001, bone marrow (BM) samples were collected from 98 children with first relapse of ALL at diagnosis. These patients were enrolled in the relapse trial ALL-REZ BFM (ALL-Relapse Berlin-Frankfurt-Munster) 95 and 96. The detection of IL-10 isoforms in leukemic cells of BM samples were performed by conventional reverse transcriptase polymerase chain reaction and by immunoblotting. RESULTS: IL-10 was detected in 93.9% BM samples. In addition to expressing full-length IL-10, a new splicing-derived IL-10 variant (termed IL-10delta3) that lacked the entire exon 3 was identified in leukemic cells. The IL-10delta3 variant was found in 80.4% of BM samples. Most importantly, expression of IL-10delta3 was associated with a significantly better response to chemotherapy (P = .001) and probability of event-free survival (P = .01) at 5 years. CONCLUSION: These results indicate that splicing-derived IL-10 isoforms may modulate IL-10-mediated biologic effects and therapeutic efficacy in lymphatic disease, and expression of IL-10delta3 is a positive prognostic feature in relapsed childhood ALL.

Effect of a single dose of rituximab in chronic immune thrombocytopenic purpura in childhood.

Twenty-two children with immune thrombocytopenic purpura (ITP) with long-lasting thrombocytopenia, adversely affecting their quality of life, were treated with a reduced rituximab regimen in order to eliminate B cells producing anti-platelet antibody. A single dose of rituximab resulted in a response rate similar to that reported for cases in which 4 doses of rituximab were used.