Phase I trial of volasertib, a Polo-like kinase inhibitor, plus platinum agents in solid tumors: safety, pharmacokinetics and activity.

BACKGROUND: This trial evaluated the maximum tolerated dose (MTD), safety, pharmacokinetics, and activity of volasertib, a selective Polo-like kinase 1 inhibitor that induces mitotic arrest and apoptosis, combined with cisplatin or carboplatin in patients with advanced/metastatic solid tumors (NCT00969761; 1230.6). METHODS: Sequential patient cohorts (3 + 3 dose-escalation design) received a single infusion of volasertib (100-350 mg) with cisplatin (60-100 mg/m(2)) or carboplatin (area under the concentration versus time curve [AUC]4-AUC6) on day 1 every 3 weeks for up to six cycles. Sixty-one patients received volasertib/cisplatin (n = 30) or volasertib/carboplatin (n = 31) for a median of 3.5 (range, 1-6) and 2.0 (range, 1-6) treatment cycles, respectively. RESULTS: The most common cycle 1 dose-limiting toxicities (DLTs) were thrombocytopenia, neutropenia and fatigue. MTDs (based on cycle 1 DLTs) were determined to be volasertib 300 mg plus cisplatin 100 mg/m(2) and volasertib 300 mg plus carboplatin AUC6. Co-administration did not affect the pharmacokinetics of each drug. Partial responses were observed in two patients in each arm. Stable disease was achieved in 11 and six patients treated with volasertib/cisplatin and volasertib/carboplatin, respectively. CONCLUSIONS: Volasertib plus cisplatin or carboplatin at full single-agent doses was generally manageable and demonstrated activity in heavily pretreated patients with advanced solid tumors.

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.

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 NH(2)-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.

Anti-B-Cell Maturation Antigen BiTE Molecule AMG 420 Induces Responses in Multiple Myeloma.

PURPOSE: The anti-B-cell maturation antigen BiTE molecule AMG 420 was assessed in patients with relapsed/refractory multiple myeloma. PATIENTS AND METHODS: In this first-in-human study, up to 10 cycles of AMG 420 were given (4-week infusions/6-week cycles). Patients had progression after ≥ 2 lines of prior therapy and no extramedullary disease. Minimal residual disease (MRD) response was defined as < 1 tumor cell/104 bone marrow cells by flow cytometry. RESULTS: Forty-two patients received AMG 420 at 0.2-800 µg/d. Median age was 65 years, and median disease duration was 5.2 years. Median exposure was 1 cycle (range, 1-10 cycles) and 7 cycles (range, 1-10 cycles) for responders. Patients discontinued for disease progression (n = 25), adverse events (AEs; n = 7), death (n = 4), completion of 10 cycles (n = 3), and consent withdrawal (n = 1). Two patients remain on treatment. There were 2 nontreatment-related deaths from AEs, influenza/aspergillosis and adenovirus-related hepatitis. Serious AEs (n = 20; 48%) included infections (n = 14) and polyneuropathy (n = 2); treatment-related serious AEs included 2 grade 3 polyneuropathies and 1 grade 3 edema. There were no grade ≥ 3 CNS toxicities or anti-AMG 420 antibodies. In this study, 800 µg/d was considered to not be tolerable because of 1 instance each of grade 3 cytokine release syndrome and grade 3 polyneuropathy, both of which resolved. The overall response rate was 31% (n = 13 of 42). At the maximum tolerated dose (MTD) of 400 µg/d, the response rate was 70% (n = 7 of 10). Of these, five patients experienced MRD-negative complete responses, and 1 had a partial response, and 1 had a very good partial response; all 7 patients responded during the first cycle, and some responses lasted > 1 year. CONCLUSION: In this study of AMG 420 in patients with relapsed/refractory multiple myeloma, the response rate was 70%, including 50% MRD-negative complete responses, at 400 µg/d, the MTD for this study.

Growth inhibition and induction of apoptosis in acute myeloid leukemia cells by new indolinone derivatives targeting fibroblast growth factor, platelet-derived growth factor, and vascular endothelial growth factor receptors.

In acute myeloid leukemia (AML), receptor tyrosine kinase ligands promote growth and survival and contribute to AML-associated marrow neoangiogenesis. We have tested simultaneous inhibition of vascular endothelial growth factor, fibroblast growth factor, and platelet-derived growth factor receptor signaling by novel indolinone derivatives using 14 myeloid, including 11 human leukemic, cell lines. Compounds inhibited colony formation of all cell lines in a dose-dependent fashion. Inhibitory concentrations for 50% of the colony formation/survival (IC50) for BIBF1000 were <100 nmol/L for 3 of 11,

An open-label, phase II study of the polo-like kinase-1 (Plk-1) inhibitor, BI 2536, in patients with relapsed small cell lung cancer (SCLC).

OBJECTIVES: This phase II, open-label study was designed to evaluate the response rate to the polo-like kinase 1 (Plk-1) inhibitor BI 2536 in patients with sensitive-relapsed small cell lung cancer (SCLC). Secondary endpoints included progression-free survival (PFS), overall survival (OS), duration of response, and safety. MATERIALS AND METHODS: Patients were treated with the recommended phase II dose of 200mg of BI 2536 intravenously every 21days. This was a two-stage design with an early stopping rule in place if responses were not seen in at least 2 of the first 18 enrolled patients. RESULTS AND CONCLUSION: Twenty-three patients were enrolled in the study and 21 patients were evaluable for response. No responses were observed and all 23 patients have progressed. The median PFS was 1.4 months. Treatment was generally well tolerated and the most frequent adverse events were neutropenia, fatigue, nausea, vomiting, and constipation. BI 2536 is not effective in the treatment of sensitive relapsed SCLC. The criteria for expanding the trial to the second stage were not achieved, and the study was terminated for a lack of efficacy.

Comprehensive Biomarker Analyses in Patients with Advanced or Metastatic Non-Small Cell Lung Cancer Prospectively Treated with the Polo-Like Kinase 1 Inhibitor BI2536.

BACKGROUND: Polo like kinase 1 (PLK1) is frequently upregulated in tumors and is thus viewed as a promising therapeutic target in various cancers. Several PLK1 inhibitors have recently been developed and clinically tested in solid cancers, albeit with limited success. So far, no predictive biomarkers for PLK1 inhibitors have been established. To this end, we conducted a post-hoc biomarker analysis of tumor samples from non-small cell lung cancer (NSCLC) patients treated with the PLK1 inhibitor BI2536 in a phase II study. METHODS: We analyzed formalin-fixed paraffin-embedded surplus tumor tissue from 47 study patients using immunohistochemistry (IHC) and DNA sequencing of KRAS, EGFR, BRAF, and PIK3CA. RESULTS: KRAS-mutated patients showed numerically prolonged progression-free survival, but statistical significance was not established. Interestingly, when pathways rather than single genes were analyzed, a positive correlation between IHC staining of activated ERK (p-ERK) and mutated KRAS was detected, whereas KRAS mutation status was found to be negatively correlated with activated AKT (p-AKT). CONCLUSION: With this hypothesis-generating study in BI2531-treated patients, we could not establish a correlation between KRAS mutations and relevant clinical endpoints. Future clinical trials with concomitant systematic biosampling and comprehensive molecular analyses are required to identify biomarkers predictive for response to PLK1 inhibitors.

3'-[18F]fluoro-3'-deoxythymidine ([18F]-FLT) as positron emission tomography tracer for imaging proliferation in a murine B-Cell lymphoma model and in the human disease.

Here we describe the evaluation of 3'-[(18)F]fluoro-3'-deoxythymidine [[(18)F]-FLT] as a tracer for positron emission tomography (PET) in a murine model of B-cell lymphoma and in human malignant lymphoma. The human B-cell line DoHH2 expressed high levels of active thymidine kinase 1 (TK-1) as the key enzyme of [(18)F]-FLT metabolism. Immunostaining confirmed high levels of TK-1 in DoHH2 derived xenograft tumors in SCID/SCID mice. In vitro studies demonstrated a time-dependent uptake of [(18)F]-FLT, an efficient phosphorylation to the respective monophosphate and the incorporation of [(18)F]-FLT into the perchloric acid insoluble fraction in DoHH2 cells, indicating the incorporation of this tracer into the DNA. After incubation with [(18)F]FLT for 240 min, 12.5% +/- 1.0% of radioactivity applied to the medium was intracellularly trapped in DoHH2 cells. Specific accumulation of [(18)F]-FLT in the malignant cell clone was confirmed in biodistribution studies in SCID/SCID mice bearing DoHH2-derived tumors. The percentage of injected dose of [(18)F]-FLT per gram of tumor tissue correlated with the tumor-proliferation index as evaluated in BrdUrd-labeling experiments. In a pilot study of 11 patients with both indolent and aggressive lymphoma, [(18)F]-FLT was suitable and comparable to [(18)F]-FDG in the ability to detect malignant lesions by PET scan. Furthermore, we found a close correlation (r = 0.95, P < 0.005) of the [(18)F]-FLT standardized uptake values with the Ki67-labeling index of tissue biopsies (n = 10) in these patients. These results suggest that [(18)F]-FLT represents a novel tracer for PET that enables imaging of proliferation in human lymphoma in vivo.

CD44v6, a target for novel antibody treatment approaches, is frequently expressed in multiple myeloma and associated with deletion of chromosome arm 13q.

BACKGROUND AND OBJECTIVES: Despite recent advances in the treatment of multiple myeloma (MM), this disease remains incurable in the majority of patients. Therefore, innovative treatment strategies are mandatory. Bivatuzumab mertansine is a novel cytotoxic immunoconjugate specifically targeting the CD44 splice variant CD44v6. To investigate the applicability of this compound to clonal plasma cell disorders, we analyzed CD44v6 expression on malignant plasma cells from patients with multiple myeloma. DESIGN AND METHODS: Bone marrow samples from 57 patients with monoclonal gammopathy of undetermined significance (MGUS), MM, and plasma cell leukemia (PCL) were examined for CD44v6 expression by using flow cytometry (FACS) analysis. In addition, all samples were investigated by fluorescence in situ hybridization (FISH) with a specific probe for the chromosomal band 13q14. RESULTS: In only 1 of 16 cases (6%) with MGUS and 1 out of 6 cases (17%) with stage I MM were plasma cells CD44v6 positive. In contrast, 43% of the cases with stage II/III MM or PCL expressed CD44v6. In these cases, CD44v6 expression was significantly correlated with chromosome 13q14 deletion as determined by FISH (p=0.02). INTERPRETATION AND CONCLUSIONS: CD44v6 is frequently expressed in advanced, high-risk MM. CD44v6 expression correlates with chromosomal band 13q14 deletions, a well-known risk factor in MM. These results suggest that this epitope is a potential new target for monoclonal antibodies such as bivatuzumab mertansine.

Mechanisms of Bcr-Abl-mediated NF-kappaB/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.

Dosimetric analysis of radioimmunotherapy with 186Re-labeled bivatuzumab in patients with head and neck cancer.

UNLABELLED: From December 1999 until July 2001, a phase I dose escalation study was performed with (186)Re-labeled bivatuzumab, a humanized monoclonal antibody against CD44v6, on patients with inoperable recurrent or metastatic head and neck cancer. The aim of the trial was to assess the safety and tolerability of intravenously administered (186)Re-bivatuzumab and to determine the maximum tolerated dose (MTD) of (186)Re-bivatuzumab. The data were also used for dosimetric analysis of the treated patients. Dosimetry is used to estimate the absorbed doses by nontarget organs, as well as by tumors. It can also help to explain toxicity that is observed and to predict organs at risk because of the therapy given. METHODS: Whole-body scintigraphy was used to draw regions around sites or organs of interest. Residence times in these organs and sites were calculated and entered into the MIRDOSE3 program, to obtain absorbed doses in all target organs except for red marrow. The red marrow dose was calculated using a blood-derived method. Twenty-one studies on 18 patients, 5 female and 16 male, were used for dosimetry. RESULTS: The mean red marrow doses were 0.49 +/- 0.03 mGy/MBq for men and 0.64 +/- 0.03 mGy/MBq for women. The normal organ with the highest absorbed dose appeared to be the kidney (mean dose, 1.61 +/- 0.75 mGy/MBq in men and 2.15 +/- 0.95 mGy/MBq in women; maximum kidney dose in all patients, 11 Gy), but the doses absorbed are not expected to lead to renal toxicity. Other organs with doses exceeding 0.5 mGy/MBq were the lungs, the spleen, the heart, the liver, the bones, and the testes. The doses delivered to the tumor, recalculated to the MTD level of 1.85 GBq/m(2), ranged from 3.8 to 76.4 Gy, with a median of 12.4 Gy. A good correlation was found between platelet and white blood cell counts and the administered amount of activity per kilogram of body weight (r = -0.79). CONCLUSION: Dosimetric analysis of the data revealed that the range of doses to normal organs seems to be well within acceptable and safe limits. Tumor doses ranged from 4 to 76 Gy. Given the acceptable tumor doses, (186)Re-labeled bivatuzumab could be a good candidate for future adjuvant radioimmunotherapy in patients with minimal residual disease.

Constitutive NF-kappab/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 Bcr-Abl induced NF-kappaB/Rel activation has previously been shown, the role of NF-kappaB/Rel in Ph+ leukemia is unclear. Using DNA binding assays, we demonstrate constitutive NF-kappaB/Rel activity in nuclear extracts from Ph+ ALL blasts, whereas Ph- primary blast cells and B-precursor cell lines lack NF-kappaB/Rel activity. NF-kappaB/Rel activity was shown in the ela2 and the b2a2 subtypes. Constitutive NF-kappaB/Rel activity in Ph+ blasts is not due to elevated endogenous IkappaB kinase (IKK) activity as shown by immune complex kinase assays. Since NF-kappaB/Rel is a transcriptional regulator of inhibitors of apoptosis we examined the expression of anti-apoptotic genes known to be induced by NF-kappaB/Rel by real time PCR analysis. We found no induction of TRAFI, TRAF2, cIAPI, cIAP2, XIAP, A20 or Bfl/Al in Ph+ ALL samples as compared to Ph-negative ALL controls. In summary, constitutive NF-kappaB/Rel activation independent of endogenous IKK activation may be a common finding in Ph+ ALL. However, targets of NF-kappaB/Rel mediated transcriptional regulation in this disease remain to be identified.

Liposomal delivery of antisense oligonucleotides for efficient downregulation of Bcl-2 and induction of apoptosis.

AIM: The aim of this study was to enhance the delivery and thus anti-tumoral efficiency of antisense bcl-2 oligonucleotides (ODN's). METHODS: Bcl-2 overexpressing DoHH2 lymphoma and HeLa-cells were transfected with ODN's using a polycationic liposome preparation. Specific hybridization of antisense ODN's was demonstrated by gel-shift assays and in vitro transcription/translation studies. Cellular uptake of oligonucleotides was evaluated by fluorescence microscopy. Inhibition of bcl-2 translation was demonstrated by quantitative RT-PCR and Western Blot. TUNEL assay, ANNEXIN V-binding and Apo-2.7 expression were performed to evaluate induction of apoptosis. RESULTS: Using polycationic liposomes, a ODN transfection rate of 95% in HeLa and 45% in DoHH2 cells were demonstrated by fluorescence microscopy. 24 hours after transfection quantitative RT-PCR detected a 56% decrease of bcl-2 mRNA in antisense and a 7% decrease in sense transfected DoHH2 cells (p < 0.05). In HeLa-cells, bcl-2 expression was almost completely inhibited 72 hours after antisense ODN transfection. Antisense treated cells also showed significant induction of apoptosis. CONCLUSIONS: Polycationic liposome-mediated transfection of bcl-2 antisense ODN's causes enhanced cellular uptake and efficient bcl-2 downregulation in bcl-2 overexpressing cell lines. This delivery strategy may explain why significant induction of apoptosis was achieved at low oligonucleotide concentrations (approximately 200 pmol/5 x 10(5) tumor cells).

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.

The Plk1 inhibitor BI 2536 in patients with refractory or relapsed non-Hodgkin lymphoma: a phase I, open-label, single dose-escalation study.

Polo-like kinase 1 (Plk1) is expressed during mitosis and overexpressed in multiple cancers, including non-Hodgkin lymphoma (NHL). This phase I study determined the maximum tolerated dose (MTD) of BI 2536, a Plk1 inhibitor, as a 1 h infusion once every 3 weeks in post-transplant relapsed (n = 17) and transplant-naive (n = 24) patients with relapsed/refractory NHL. Median treatment cycles were 2 and 1.5, respectively. MTD was 175 mg for both populations; dose-limiting toxicities were grade 4 thrombocytopenia and neutropenia. Most treatment-related adverse events were grade 1/2; drug-related grade 3/4 events included thrombocytopenia and neutropenia. Four patients achieved responses (three complete and one partial at doses ≥ 150 mg, all post-transplant relapsed patients) for an overall response rate of 9.8%. BI 2536 exhibited multi-compartmental pharmacokinetics with a high volume of distribution. The activity and safety of BI 2536 in this pretreated patient population support Plk inhibitors as a therapeutic strategy in oncology.

A phase I, dose-escalation study of the novel Polo-like kinase inhibitor volasertib (BI 6727) in patients with advanced solid tumours.

BACKGROUND: Volasertib (BI 6727) is a potent and selective cell-cycle kinase inhibitor that induces mitotic arrest and apoptosis by targeting Polo-like kinase (Plk). This phase I dose-escalation study evaluated the maximum tolerated dose (MTD) of volasertib, safety and efficacy, and pharmacokinetic (PK) parameters. METHODS: This trial followed an open-label, toxicity-guided dose-titration design. Patients with progressive advanced or metastatic solid tumours received a single 1-h infusion of volasertib every 3 weeks. A total of 65 patients were treated at doses of 12-450 mg. RESULTS: Reversible haematological toxicity was the main side-effect; thrombocytopenia, neutropenia, and febrile neutropenia constituting the main dose-limiting events. Anaemia (all grades 22%; grade 3: 8%), neutropenia (15%; grade 3/4: 14%), fatigue (15%; grade 3: 2%), and thrombocytopenia (14%; grade 3/4: 14%) were the most frequent drug-related adverse events. The MTD was 400mg; however, 300 mg was the recommended dose for further development based on overall tolerability. Three patients achieved confirmed partial response. Stable disease as best response was reported in 40% of patients. Two patients remained progression free for >1 year. PK analysis showed no indication of deviation from 'dose-linear PK' behaviour, a large volume of distribution (>4000 l), moderate clearance and a long half-life (~111 h). CONCLUSION: This first-in-man trial demonstrated a favourable PK profile of volasertib, with manageable toxicities. As expected, the most common events were haematological. Encouraging preliminary antitumour activity has been observed, supporting Plk inhibition as a therapeutic approach. Clinical development of volasertib in phase II monotherapy and combination trials is ongoing.

Comparison of different semi-mechanistic models for chemotherapy-related neutropenia: application to BI 2536 a Plk-1 inhibitor.

PURPOSE: The aim of this investigation was to compare the performance of a commonly used semi-mechanistic model for drug-related neutropenia with other semi-mechanistic models published in the literature. METHODS: After their implementation in NONMEM VI, five semi-mechanistic models were assessed using the pharmacokinetic and absolute neutrophil count data obtained from 95 patients with non-small cell lung cancer receiving either 200 mg on day 1 or 50 or 60 mg on days 1, 2 and 3 of a 21-day treatment course with the new Plk-1 inhibitor BI 2536. The model performance was compared by means of predictive (visual and numerical) checks, precision in the parameter estimates and objective function-based measures. Details of model parameterization, model stability and run times are also provided. RESULTS: The time course of the drug plasma concentrations was described by a three compartment model with a first-order elimination rate. With respect to neutropenia, all models were successfully implemented in NONMEM and provided reasonable fits for the median (although not all models described all percentiles of the data well), and in general precise parameter estimates. CONCLUSION: In the current evaluation performed in a single drug, none of the models showed superior performance compared to the most commonly used model first described by Friberg et al. (J Clin Oncol 20:4713-4721, 2002).

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.

Semi-mechanistic population pharmacokinetic/pharmacodynamic model for neutropenia following therapy with the Plk-1 inhibitor BI 2536 and its application in clinical development.

PURPOSE: (1) To describe the neutropenic response of BI 2536 a polo-like kinase 1 inhibitor in patients with cancer using a semi-mechanistic model. (2) To explore by simulations (a) the neutropenic effects for the maximum tolerated dose (MTD) and the dose at which dose-limiting toxicity occurred, (b) the possibility to reduce the cycle duration without increasing neutropenia substantially, and (c) the impact of the initial absolute neutrophil count (ANC) on the degree of neutropenia for different doses. EXPERIMENTAL DESIGN: BI 2536 was administered as intravenous infusion over 60 min in the dose range from 25 to 250 mg. Three different administration schedules were explored: (a) day 1, (b) days 1, 2, and 3 or (c) days 1 and 8 within a 3 week treatment cycle. BI 2536 plasma concentrations and ANC obtained during the first treatment cycle from 104 patients were analysed using the population approach with NONMEM VI. RESULTS: Neutropenia was described by a semi-mechanistic model resembling proliferation at the stem cell compartment, maturation, degradation, and homeostatic regulation. BI 2536 acts decreasing proliferation rate. Simulations showed that (1) all MTD doses showed an acceptable risk of neutropenia, (2) when BI 2536 is given as 200 mg single administration, cycle duration can be reduced from 3 to 2 weeks, and (3) baseline ANC might be considered to individualise the dose of BI 2536. CONCLUSIONS: A semi-mechanistic population model was applied to describe the neutropenic effects of BI 2536. The model was used for simulations to support further clinical development.

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.