Gerd Munzert

Phase I Dose Escalation and Pharmacokinetic Study of BI 2536, a Novel Polo-Like Kinase 1 Inhibitor, in Patients With Advanced Solid Tumors

PURPOSE BI 2536 is a novel, potent, and highly specific inhibitor of polo-like kinase 1 (Plk1), which has an essential role in the regulation of mitotic progression. The aim of this trial was to identify the maximum tolerated dose (MTD) of BI 2536 and to determine the safety, pharmacokinetics, and antitumor activity in patients who had advanced solid tumors. PATIENTS AND METHODS This phase I trial followed an open label, toxicity-guided, dose-titration design. Single doses of BI 2536 (25 to 250 mg) were administered as a 1-hour intravenous infusion; patients who experienced clinical benefit were eligible for additional treatment courses. Safety and pharmacokinetics were investigated. Tumor response was evaluated according to Response Evaluation Criteria in Solid Tumors Group guidelines. RESULTS The MTD was defined at 200 mg in a total of 40 patients entered; reversible neutropenia constituted the dose-limiting toxicity (DLT) and the most frequent adverse event at the MTD (grade 3 to 4; 56%). Nausea (52%), fatigue (52%), and anorexia (44%) also were common and were mostly of mild to moderate intensity (Common Terminology Criteria of Adverse Events <or= grade 2). One patient experienced a transient partial response. At doses equal to or greater than the MTD, 23% of patients experienced disease stabilization for 3 or more months. Dose-proportional increases in the maximum plasma concentration and total exposure were observed. BI 2536 showed a high total clearance and high distribution into tissue. CONCLUSION The MTD of BI 2536 when administered as a single-dose, 1-hour infusion was 200 mg; BI 2536 was well tolerated and showed a favorable pharmacokinetic profile. Antitumor activity of BI 2536 was observed.

Mechanisms of Bcr-Abl-mediated NF-κB/Rel activation

Bcr-Abl constitutes a deregulated tyrosine kinase involved in the pathogenesis of chronic myeloid leukemia (CML) and a subset of acute lymphoblastic leukemia (ALL). Although activation of the transcription factor NF-kappaB/Rel has been demonstrated, mechanisms of NF-kappaB/Rel activation by Bcr-Abl remain obscure. In this paper we demonstrate activation of NF-kappaB/Rel by Bcr-Abl and for the first time by v-Abl. Furthermore, we investigated mechanisms of NF-kappaB/Rel induction by Bcr-Abl and v-Abl. Both Bcr-Abl and v-Abl induced NF-kappaB/Rel DNA binding in Ba/F3 cells. DNA binding was a result of nuclear translocation of p65/RelA, whereas p65/RelA expression was unaffected. Nuclear translocation of p65/RelA is at least partially due to increased IkappaBalpha degradation, which is independent of IkappaB kinase (IKK) activity. IKK activity is not deregulated by Bcr-Abl and v-Abl. NF-kappaB/Rel transactivation was dependent on abl kinase activity but independent of Grb2 and Grb10 binding tobcr sequences. In addition, NF-kappaB/Rel activation was dependent on Ras activity. Primary CML blasts showed constitutive p65/RelA NF-kappaB/Rel DNA binding activity. Thus NF-kappaB/Rel represents a potential target for molecular therapies in CML.

An Open-Label, Phase I Study of the Polo-like Kinase-1 Inhibitor, BI 2536, in Patients with Advanced Solid Tumors

Purpose: This phase I, open-label, dose-escalation study investigated the maximum tolerated dose (MTD) of BI 2536, a small-molecule polo-like kinase (Plk)–1 inhibitor, in two treatment schedules in patients with advanced solid tumors. Secondary objectives included evaluation of safety, efficacy, and pharmacokinetics. Experimental Design: Patients received a single i.v. dose of BI 2536 as a 1-hour infusion on days 1 and 8 or a single 24-hour infusion on day 1 of each 21-day treatment course. MTD determination was based on dose-limiting toxicities. Results: Forty-four and 26 patients received each treatment schedule, respectively. The MTD of BI 2536 in the day 1 and 8 schedule was 100 mg per administration (200 mg per course). The MTD for the second dosing schedule was not determined; a 225-mg dose was well tolerated. The most frequently reported treatment-related nonhematologic adverse events were gastrointestinal events and fatigue. Hematotoxicity as the most relevant side effect was similar in both schedules; neutropenia grades 3 and 4 were observed in 16 patients (36.4%) of the day 1 and 8 schedule and 13 patients (50%) of the 24-hour infusion. Fourteen patients (32%) treated in the day 1 and 8 dosing schedule had a best overall response of stable disease. Plasma concentrations of BI 2536 increased dose proportionally, with no relevant accumulation of exposure in the day 1 and 8 dosing schedule. The average terminal half-life was 50 hours. Conclusions: BI 2536 administered in either treatment schedule has adequate safety in patients with advanced solid tumors, warranting further clinical investigation of polo-like kinase–1 inhibitors. Clin Cancer Res; 16(18); 4666–74. ©2010 AACR.

The Efficacy and Safety of BI 2536, a Novel Plk-1 Inhibitor, in Patients with Stage IIIB/IV Non-small Cell Lung Cancer Who Had Relapsed after, or Failed, Chemotherapy Results from an Open-Label, Randomized Phase II Clinical Trial

Objective: To investigate the efficacy, safety, and pharmacokinetics of two dosing schedules of BI 2536, a novel polo-like kinase-1 inhibitor, in patients with relapsed stage IIIB/IV non-small cell lung cancer. Methods: Ninety-five patients were randomized to intravenous BI 2536 on day 1 (200 mg) or days 1 to 3 (50 or 60 mg) of a 21-day treatment course. BI 2536 doses were escalated beyond course 2 if well tolerated. The primary objective was response, and the secondary objectives were progression-free survival (PFS) and overall survival (OS), quality of life, safety, and pharmacokinetics. Primary statistical aim was to demonstrate the difference in objective response rate to historical placebo for both treatment groups. Results: Four patients (4.2%) had a partial response; two were confirmed by independent review. Median PFS was 8.3 weeks (58 days 95% confidence interval [CI]: 48–85) and 7 weeks (49 days 95% CI: 46–70) assessed by investigator and independent review, respectively. Median OS was 28.7 weeks (201 days 95% CI: 180–305). No statistically significant difference was observed between the two treatment schedules regarding clinical benefit, PFS, or OS. Grade 4 neutropenia occurred in 37% of patients; common nonhematologic adverse events were fatigue (31%) and nausea (27%). Two deaths (pulmonary hemorrhage and sepsis) were considered drug related. There was a trend in favor of the days 1 to 3 dosing schedule in quality of life. BI 2536 displayed moderate interpatient variability. Conclusions: BI 2536 monotherapy has modest efficacy and favorable safety in relapsed non-small cell lung cancer. The findings support the further development of polo-like kinase-1 inhibitors within this indication.

Constitutive NF-κB/Rel Activation in Philadelphia Chromosome Positive (Ph+) Acute Lymphoblastic Leukemia (ALL)

The Bcr-Abl translocation t(9;22)(q34;q11) defines a subgroup of ALL patients with a dismal prognosis despite the introduction of intensified induction and consolidation regimen. Although BcrAbl induced NF-kB/Rel activation has previously been shown, the role of NF-kB/Rel in Ph+ leukemia is unclear. Using DNA binding assays, we demonstrate constitutive NF-kB/Rel activity in nuclear extracts from Ph+ ALL blasts, whereas Ph7 primary blast cells and B-precursor cell lines lack NF-kB/Rel activity. NF-kB/Rel activity was shown in the e1a2 and the b2a2 subtypes. Constitutive NF-kB/Rel activity in Ph+ blasts is not due to elevated endogenous IkB kinase (IKK) activity as shown by immune complex kinase assays. Since NF-kB/Rel is a transcriptional regulator of inhibitors of apoptosis we examined the expression of anti-apoptotic genes known to be induced by NF-kB/Rel by real time PCR analysis. We found no induction of TRAF1, TRAF2, cIAP1, cIAP2, XIAP, A20 or Bfl/A1 in Ph+ ALL samples as compared to Ph7negative ALL controls. In summary, constitutive NF-kB/Rel activation independent of endogenous IKK activation may be a common finding in Ph+ ALL. However, targets of NF-kB/Rel mediated transcriptional regulation in this disease remain to be identified.

Phase i study of the Plk1 inhibitor BI 2536 administered intravenously on three consecutive days in advanced solid tumours

BACKGROUND This open-label phase i study with an accelerated titration design was performed to determine the maximum tolerated dose of BI 2536, a potent, highly selective small-molecule polo-like kinase 1 (Plk1) inhibitor. METHODS Patients with advanced solid tumours received a single 60-minute intravenous infusion of BI 2536 (50-70 mg) on days 1-3 of each 21-day treatment course. Recipients without disease progression or untenable toxicity could receive additional treatment courses. The maximum tolerated dose was determined based on dose-limiting toxicities. Other assessments included safety, pharmacokinetic profile, and antitumour activity according to the Response Evaluation Criteria in Solid Tumors. RESULTS The study enrolled 21 patients. The maximum tolerated dose for BI 2536 was determined to be 60 mg for the study schedule. Dose-limiting toxicities included hematologic events, hypertension, elevated liver enzymes, and fatigue. The most frequently reported drug-related adverse events were mild-to-moderate fatigue, leukopenia, constipation, nausea, mucosal inflammation, anorexia, and alopecia. The pharmacokinetics of BI 2536 were linear within the dose range tested. Plasma concentration profiles exhibited multi-compartmental pharmacokinetic behaviour, with a terminal elimination half-life of 20-30 hours. CONCLUSIONS In the present study, BI 2536 showed an acceptable safety profile warranting further investigation of Plk1 inhibitors in this patient population.

A Phase I Open-Label Dose-Escalation Study of Intravenous BI 2536 Together With Pemetrexed in Previously Treated Patients With Non–Small-Cell Lung Cancer

INTRODUCTION BI 2536 is a potent, highly selective inhibitor of polo-like kinase (Plk) 1. This open-label, phase I study investigated the maximum tolerated dose (MTD), safety, efficacy, and pharmacokinetics (PK) of BI 2536 IV in combination with standard-dose pemetrexed in previously treated advanced or metastatic non-small-cell lung cancer. PATIENTS AND METHODS A standard 3 + 3 design was used. The patients received 500 mg/m(2) pemetrexed and escalating doses of BI 2536 on day 1 every 3 weeks. The primary objective was the MTD of BI 2536 combined with pemetrexed. Secondary endpoints were response rate (Response Evaluation Criteria in Solid Tumors), overall safety, and PK. RESULTS Forty-one patients received BI 2536 (100-325 mg). Two dose-limiting toxicities (DLT) occurred at BI 2536 325 mg (grade 3 pruritus and rash; grade 4 neutropenia). Therefore, the MTD for BI 2536 in combination with pemetrexed was 300 mg. After expanding the MTD dose level, 3 additional patients experienced DLTs, which resulted in expansion of the 250 mg cohort, in which 4 of the 13 additional patients experienced DLTs. Therefore, the recommended dose of BI 2536 was 200 mg. Most frequently reported drug-related adverse events were fatigue (71%), nausea (37%), and rash (34%). Two patients had durable confirmed partial responses; 21 (54%) patients had stable disease after the treatment cycle 2. PK analysis showed that BI 2536 and pemetrexed exposure were not altered when coadministered. CONCLUSION BI 2536 200 mg combined with standard-dose pemetrexed has an acceptable safety profile in relapsed non-small-cell lung cancer. The antitumor activity observed is encouraging and supports further investigation of Plk inhibitors.

Bortezomib, Dexamethasone, and Fibroblast Growth Factor Receptor 3–Specific Tyrosine Kinase Inhibitor in t(4;14) Myeloma

Purpose: Novel drugs including targeted approaches have changed treatment paradigms for multiple myeloma (MM) and may also have therapeutic potential in the poor-prognosis t(4;14) subset; t(4;14) results in overexpressed and activated fibroblast growth factor receptor 3 (FGFR3). Blocking this receptor tyrosine kinase (RTK) induces apoptosis in t(4;14)+ MM cells and decreases adhesion to bone marrow stromal cells (BMSC). Using combinations of novel drugs, we investigated potential enhancement of single-agent activities within the tumor cells, targeting of the marrow micromilieu, or circumvention of drug resistance in t(4;14)+ MM. Experimental Design: We tested effects on apoptosis and related signaling pathways in the t(4;14)+ MM subset, applying drug combinations including a FGFR3 tyrosine kinase inhibitor (RTKI), the proteasome inhibitor bortezomib, and dexamethasone. Results: RTKI, bortezomib, and dexamethasone were active as single agents in t(4;14)+ MM. RTK inhibition triggered complementary proapoptotic pathways (e.g., decrease of Mcl-1, down-regulation of p44/42 mitogen-activated protein kinase, and activation of proapoptotic stress-activated protein/c-Jun NH2-terminal kinases). Synergistic or additive effects were found by combinations of RTKI with dexamethasone or bortezomib. In selected cases of t(4;14)+ MM, triple combinations were superior to dual combinations tested. Prevention from MM cell apoptosis by BMSC or exogenous interleukin-6 was circumvented by drug combinations. In t(4;14)+, N-ras–mutated NCI-H929 cells, resistance to RTKI was overcome by addition of dexamethasone. Notably, the combination of RTKI and dexamethasone showed additive proapoptotic effects in bortezomib-insensitive t(4;14)+ MM. Conclusions: Combining novel drugs in poor-prognosis t(4;14)+ MM should take into account at least bortezomib sensitivity and probably Ras mutational status.

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.

Prediction of Neutropenia-Related Effects of a New Combination Therapy With the Anticancer Drugs BI 2536 (a Plk1 Inhibitor) and Pemetrexed

This study investigated the feasibility of predicting the neutropenia‐related effects of a therapy that combines the investigational drug BI 2536 (inhibitor of Polo‐like kinase 1) and pemetrexed, an approved anticancer drug. Predictions were arrived at using the pharmacokinetic/pharmacodynamic (PK/PD) parameters of each of the drugs obtained from monotherapy studies and assuming that the neutropenic effect is additive when the drugs are administered as a combination therapy. Subsequently, a PK/PD model was developed to determine whether this assumption of additive effect was reasonable in relation to these two drugs. All analyses and simulations were performed using the population approach in NONMEM, version VI.