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.

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.

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.

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.

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 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.

A randomised phase II trial of the Polo-like kinase inhibitor BI 2536 in chemo-naïve patients with unresectable exocrine adenocarcinoma of the pancreas - a study within the Central European Society Anticancer Drug Research (CESAR) collaborative network

BACKGROUND

BI 2536, a novel Polo-like kinase 1 inhibitor, was assessed in patients with unresectable advanced exocrine adenocarcinoma of the pancreas.

METHODS

The study employed a two-stage design. Randomised first-line patients received BI 2536 200 mg on day 1 (n=43) or 60 mg on days 1-3 (n=43) every 21 days. Recruitment of second-line patients was planned for a second stage dependent on an interim analysis demonstrating ≥ 2 responses in the first 18 evaluable patients following 12 weeks of treatment and/or tumour control ≥ 12 weeks in 5 patients per schedule. Primary end point was objective response rate (ORR).

RESULTS

By independent review, ORR was 2.3% (all partial) and 24.4% had stable disease as confirmed best response. The second stage was not initiated. Median overall and progression-free survivals were 149 (95% confidence interval (CI), 91-307) and 46 days (95% CI, 44-56). Most common drug-related adverse events were neutropenia (37.2%), leukopenia (29.1%), fatigue (29.1%) and nausea (22.1%); most common grade 3/4-related events were neutropenia (36.0%), leukopenia (27.9%) and thrombocytopenia (8.1%).

CONCLUSION

Given the low ORR and poor survival, further development of BI 2536 monotherapy is not warranted in this population.

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.

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).

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.

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.

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.

An open-label dose-escalation study of BIBF 1120 in patients with relapsed or refractory multiple myeloma

BACKGROUND

To determine the maximum tolerated dose (MTD) and dose-limiting toxicities (DLTs) of BIBF 1120, a triple angiokinase inhibitor administered once-daily in patients with advanced multiple myeloma.

PATIENTS AND METHODS

This Phase I study included 17 patients. Planned dose escalations of BIBF 1120 were 100, 200, 250 and 300 mg. Safety and pharmacokinetic (PK) assessments were performed.

RESULTS

Two DLTs (200 and 250 mg) occurred due to increased gamma-glutamyltransferase levels (CTC grade 3). The 250 mg dose was well tolerated; no dose escalation beyond 250 mg was made. The most common adverse events included diarrhoea, nausea and vomiting. No detectable deviation from dose linear PKs was observed. Regarding tumour control, two patients had stable disease for > or = 4 months.

CONCLUSION

BIBF 1120 was safe and well tolerated up to 250 mg/day. The MTD was not reached.

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 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.

An open label phase II trial of the Plk1 inhibitor BI 2536, in patients with sensitive relapse small cell lung cancer (SCLC)

8108

Background: BI 2536 is a potent, selective inhibitor of polo-like kinase 1 (Plk1), a regulator of mitotic progression. BI 2536 demonstrated favorable tolerability and antitumor activity in phase I trials. We investigated the antitumor efficacy, safety and PK of BI 2536 in patients (pts) with sensitive relapse SCLC. Methods: This open label single arm phase II study followed a Gehan two-stage design. Primary objective was to determine the antitumor efficacy of BI 2536 in SCLC pts with disease recurrence ≥60 days after completion of first-line chemotherapy. 18 pts had to complete 2 courses to be evaluable for stage 1 analysis. In case of ≥2 partial or complete antitumor responses (RECIST criteria), stage 2 accrual would continue until 40 pts were entered. Patients received 200 mg BI 2536 as a 1h i.v. infusion on Day 1 every 3 weeks. Dose escalation to 250 mg (cycle 3 onwards) was encouraged in pts with <Grade 2 drug related non-hematologic and <Grade 3 hematologic toxicity. Results: 23 pts (14 female, 9 male, 21 extensive disease, 2 limited disease), median age 60 yrs (range: 35–77) were treated. All patients had disease recurrence >60 days after completion of first-line therapy. Of 23 pts, no objective antitumor responses were observed, 7 had stable disease as best response, 14 had progression, 2 were not evaluable. A median of 2 courses were given, up to a maximum of 12 in 1 pt. The PFS rate at 3 months was 25%. Due to the lack of antitumor responses, trial accrual was terminated after stage 1. Overall, BI 2536 was well tolerated. Frequent AEs were neutropenia (48%), fatigue (39%), nausea (30%), anemia, vomiting, constipation (26% each), and thrombocytopenia (22%). Drug related grade 3/4 AEs were neutropenia (13%/26%), grade 3/4 thrombocytopenia (1 pt each), grade 3/4 anemia (1 pt each), grade 4 sepsis (1 pt), Grade 4 ARDS (1 pt) and Grade 3 fatigue (1 pt). PK analyses indicate that BI 2536 has high clearance (>1,000 mL/min) and quickly distributes in multiple compartments in a large volume of distribution (>1,000 L). Estimated elimination half-life was >25 h. Conclusions: BI 2536 was well tolerated in relapsed SCLC pts, but demonstrated no convincing antitumor efficacy after stage I of the study. Therefore, BI 2536 will not be assessed further as a single agent in SCLC.

[Table: see text]

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

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.

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Key Words Collapse

MESH Headings

• Adult
• Aged
• Antineoplastic Agents/pharmacology
• Cell Cycle Proteins/antagonists & inhibitors
• Dose-Response Relationship, Drug
• Enzyme Inhibitors/pharmacology
• Female
• Humans
• Infusions, Intravenous
• Male
• Maximum Tolerated Dose
• Middle Aged
• Neoplasms/drug therapy
• Protein Serine-Threonine Kinases/antagonists & inhibitors
• Protein Structure, Tertiary
• Proto-Oncogene Proteins/antagonists & inhibitors
• Pteridines/pharmacology
• Polo-Like Kinase 1

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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, <or=500 nmol/L for 6 of 11, and <1,000 nmol/L for 10 of 11 leukemic cell lines, with one cell line being resistant in the dose range <1,000 nmol/L. BIBF1120 was less effective with 4 of 11 leukemic cell lines being resistant within the dose range <1,000 nmol/L. Testing of myeloid 32D cells transfected with empty vector, wild-type Flt3, or Flt3 carrying an internal tandem duplication mutation revealed higher resistance for the internal tandem duplication mutant. These effects of the compounds were associated with inhibition of tyrosine phosphorylation and the mitogen-activated protein kinase pathway. Furthermore, both compounds induced apoptosis in the sensitive cell lines. In Mono-Mac1 cells, the compounds had a direct proapoptotic effect that was increasing the proapoptotic effect of 1-beta-D-arabinofuranosylcytosine. The data provide a rationale for clinical evaluation of these tyrosine kinase inhibitors in AML.

A phase I repeated dose escalation study of the Polo-like kinase 1 inhibitor BI 2536 in patients with advanced solid tumours

2038

Background: BI 2536 is a novel highly potent and selective inhibitor of the serine-threonine kinase polo-like kinase 1 (Plk1), which is a key regulator of cell cycle progression. Objectives of this trial were the assessment of the maximum tolerated dose (MTD), overall safety, pharmacokinetics and efficacy of BI 2536 given intravenously. Methods: Sequential cohorts of 3 to 6 patients (pts) with pretreated advanced or metastatic solid tumours received intravenous infusions of BI 2536 on days 1 and 8 of a 3-week treatment course following a toxicity guided dose escalation design. Further treatment courses were administered to pts in the absence of disease progression and if toxicity after a 3-week treatment course had resolved. Results: A total of 42 pts was treated at doses of 25 mg (n=3), 50 mg (n=3), 100 mg (n=22), 125 mg (n=5), 150 mg (n=6) and 200 mg (n=3). Reversible CTCAE grade ≥ 3 neutropenia in 14/42 pts represented the main drug related toxicity with an incidence of 3/5 in the 125 mg cohort, 4/6 in the 150 mg and 2/2 in the 200 mg dose cohorts. Dose limiting toxicity (DLT) was defined as drug related toxicity prohibiting administration of the day 8 dose of BI 2536 (hematologic: CTCAE ≥ 3 grade, non-hematologic toxicity: CTCAE ≥ 2). No DLT other than d8 neutropenia was observed. The MTD was defined at 100 mg for the given day 1 and 8 schedule. Further related adverse events (AE’s) were of mild to moderate intensity (CTCAE grade ≤ 2). There were no related AEs resulting in study discontinuation. Preliminary PK analysis showed dose proportionality of Cmax and AUC0-∞ with a high clearance (∼ 1500 mL/min) and a high volume of distribution (∼ 2000 L). No accumulation from d1 to d8 occurred. Patients were treated for up to 8 courses without evidence of accumulating toxicity. No objective responses were observed according to RECIST criteria in this heavily pretreated patient population. Conclusions: In summary BI 2536 is a Plk1 inhibitor with a favorable PK and safety profile at the tested dose and schedule. Neutropenia as a mechanism-related toxicity indicates target inhibition in vivo.

[Table: see text]

A phase I study of two administration schedules of the Polo-like kinase 1 inhibitor BI 2536 in patients with advanced solid tumors

3069

Background: BI 2536 is a novel highly potent and selective inhibitor of the serine-threonine Polo-like kinase 1 (Plk1), a key regulator of cell cycle progression. Objectives of this trial were the assessment of the maximum tolerated dose (MTD), overall safety, pharmacokinetics and preliminary efficacy of BI 2536 given intravenously. Methods: Sequential cohorts of 3–6 patients (pat) with advanced or metastatic solid tumors received infusions of BI 2536 following a toxicity guided dose escalation design. In the first part of the trial, a single administration was given every 21 days (d1). After completion of accrual BI 2536 was administered on three consecutive days (d1–3) in a dose intensified schedule in additional patient cohorts. Further treatment courses were given in the absence of disease progression and after recovery of toxicity after a 3-week observation period. Results: Of the 52 entered patients a total of 40 pts were treated at doses of 25 (n=3), 50 (n=3), 100 (n=3), 200 (n=25) and 250 mg (n=6) in the d1 schedule. The MTD for the d1 schedule was defined at 200 mg. Dose limiting toxicity (DLT) consisted of neutropenic infection and occurred in 2/6 patients at 250 mg. Reversible CTCAE grade ≥ 3 neutropenia represented the main drug related toxicity with an incidence of 13/25 in the 200 mg and 5/6 in the 250 mg dose cohorts. Alopecia was reported in 20% of pat. Further common drug related adverse events (AE’s) consisted of nausea (38%), anorexia (25%) fatigue (18%), vomiting (18%) and mucositis (12%) and were mostly of mild to moderate intensity (CTCAE grade ≤ 2). PK analysis showed dose proportionality of Cmax and AUC0-∞ with a high clearance (∼ 1400 mL/min) and a high volume of distribution (∼ 1200 L). A correlation between exposure and neutropenia was observed. Patients were treated for up to 10 courses without evidence of accumulating toxicity. One partial response was observed in a patient with metastatic squamous cell head and neck cancer treated at 250 mg. The DLT was determined at 3x70 mg in the dose intensified schedule with the MTD still pending. Conclusion: In summary BI 2536 is a Plk1 inhibitor with a favorable safety and PK profile. Neutropenia as a mechanism-related toxicity indicates target inhibition in vivo. First signs of antitumor activity were observed.

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Targeting receptor kinases by a novel indolinone derivative in multiple myeloma: abrogation of stroma-derived interleukin-6 secretion and induction of apoptosis in cytogenetically defined subgroups

In multiple myeloma (MM), both vascular endothelial (VEGF) and basic fibroblast growth factor (bFGF) promote tumor growth and survival. We have used the novel indolinone BIBF 1000 to study effects of simultaneous inhibition of VEGF, FGF and transforming growth factor-beta on MM cells and their interactions with bone marrow stroma cells (BMSCs). Both, in the absence and presence of myeloma-stroma cell contacts, BIBF 1000 abrogated BMSC-derived secretion of interleukin-6 (IL-6). In addition, BIBF 1000 directly induced apoptosis in t(4;14)-positive cell lines as well as in CD138+ marrow cells from patients with t(4;14) myeloma. To a similar extent, BIBF 1000 induced apoptosis in MM.1S and MM.1R cells carrying the translocation t(14;16). In case of MM.1S and other dexamethasone-sensitive t(14;16) cell lines, BIBF 1000 and dexamethasone had additive proapoptotic effects. Induction of apoptosis by BIBF 1000 was associated with inhibition of the mitogen-activated protein kinases (MAPK) pathway in t(4;14) and inhibition of the phosphatidyl-inositol-3 kinase/AKT pathway in t(14;16) cells. Apoptotic effects did not occur in t(4;14)-or t(14;16)-positive MM cells carrying n- or k-Ras mutations. The data provide the rationale for clinical evaluation of this class of targeted kinase inhibitors in MM with focus on defined cytogenetic subgroups.

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.

CD44v6: a target for antibody-based cancer therapy

The human CD44 gene encodes type 1 transmembrane glycoproteins involved in cell-cell and cell-matrix interactions. The structural heterogeneity of the gene products is caused primarily by alternative splicing of at least 10 out of 20 exons. Certain CD44 variant isoforms, in particular those containing CD44 variant domain 6 (CD44v6), have been implicated in tumourigenesis, tumour cell invasion and metastasis. Here we will give an overview of immunohistochemically determined CD44v6 expression in human malignancies (primary epithelial and nonepithelial tumours as well as metastases) and normal tissues, and review several examples of the clinical use of CD44v6-specific antibodies. In nonmalignant tissues, CD44v6 expression is essentially restricted to a subset of epithelia. Intense and homogeneous expression of CD44v6 was reported for the majority of squamous cell carcinomas and a proportion of adenocarcinomas of differing origin, but was rarely seen in nonepithelial tumours. This expression pattern has made CD44v6 an attractive target for antibody-guided therapy of various types of epithelium-derived cancers.

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

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.

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.

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.

Tumor necrosis factor receptor-associated factor 1 gene overexpression in B-cell chronic lymphocytic leukemia: analysis of NF-kappa B/Rel-regulated inhibitors of apoptosis

B-cell chronic lymphocytic leukemia (B-CLL) is characterized by a resistance toward apoptosis-inducing agents. Nuclear factor-kappaB (NF-kappaB)/Rel has been shown to regulate the expression of antiapoptotic genes, such as members of the inhibitor of apoptosis protein (IAP) and tumor necrosis factor receptor-associated factor (TRAF) gene families. Expression and regulation of NF-kappaB/Rel-dependent inhibitors of apoptosis have not been collectively studied in B-CLL. We examined expression of known NF-kappaB/Rel-regulated antiapoptotic genes by RNAse protection assay, real-time polymerase chain reaction, and immunoblotting in patients with B-CLL. TRAF1 and to a lesser extent TRAF2 were overexpressed in B-CLL lymphocytes as compared with normal CD19(+) B cells. TRAF1 overexpression did not correlate with markers of disease progression or overall survival. Furthermore, we found high constitutive expression of the IAP genes c-IAP-1, c-IAP-2, and XIAP both in normal and B-CLL lymphocytes. Focusing on the regulation of TRAF1, NF-kappaB/Rel activity in B-CLL nuclear extracts was shown to bind to TRAF1 promoter elements. However, IkappaB kinase (IKK) activity was not increased in CLL lymphocytes as compared with normal CD19(+) B cells. The known IKK inhibitor sulfasalazine did not compromise TRAF1 expression. Thus, although our study revealed a common expression pattern of NF-kappaB/Rel-regulated inhibitors of apoptosis, our findings indicate an IKK-independent regulation of TRAF1 in B-CLL.

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).

Leading prognostic relevance of the BCR-ABL translocation in adult acute B-lineage lymphoblastic leukemia: a prospective study of the German Multicenter Trial Group and confirmed polymerase chain reaction analysis

The BCR-ABL fusion, the molecular equivalent of the Philadelphia translocation, gains importance for treatment stratification in adult acute lymphoblastic leukemia (ALL). In this prospective study, samples from 478 patients with CD10(+) B-cell precursor ALL (c-ALL and pre-B ALL) underwent BCR-ABL reverse transcription-polymerase chain reaction (RT-PCR) analysis with double testing of positive samples. Patients were stratified according to the PCR result and treated in 2 German Multicenter Trials of Adult ALL. The outcome was followed and the prognostic impact of BCR-ABL was compared to clinical risk features. Of the 478 samples, 432 had an evaluable BCR-ABL result. Thirty-seven percent of the c-ALL and pre-B ALL patients were BCR-ABL(+) (p190, 77%; p210, 20%; simultaneous p190/p210, 3%). BCR-ABL positivity was associated with the high-risk features of older age (45 years versus 30 years median age; P =.0001) and higher white blood cell counts (23 500/microL versus 11 550/microL; P =.0001). Univariate and multivariate analyses revealed BCR-ABL as the leading factor for a poor prognosis (P =.0001) in comparison to clinical risk criteria. Irrespective of the breakpoint, presence of any BCR-ABL transcript predicted a lower chance of initial treatment response (68.4% versus 84.6%; P =.001) and a lower probability of disease-free survival at 3 years (0.13 versus 0.47; P =.0001). This bad outcome was not influenced by postinduction high-dose treatment stratifications. The results show a high prevalence of BCR-ABL fusion transcripts with predominance of p190. BCR-ABL RT-PCR is confirmed as a sensitive, rapid method to diagnose t(9;22), and p190 and p210 are unequivocally demonstrated as the most important predictors of poor long-term survival despite intensified chemotherapy.

Rhenium 188-labeled anti-CD66 (a, b, c, e) monoclonal antibody to intensify the conditioning regimen prior to stem cell transplantation for patients with high-risk acute myeloid leukemia or myelodysplastic syndrome: results of a phase I-II study

The conditioning regimen prior to stem cell transplantation in 36 patients with high-risk acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS) was intensified by treating patients with a rhenium 188-labeled anti-CD66 monoclonal antibody. Dosimetry was performed prior to therapy, and a favorable dosimetry was observed in all cases. Radioimmunotherapy with the labeled antibody provided a mean of 15.3 Gy of additional radiation to the marrow; the kidney was the normal organ receiving the highest dose of supplemental radiation (mean 7.4 Gy). Radioimmunotherapy was followed by standard full-dose conditioning with total body irradiation (12 Gy) or busulfan and high-dose cyclophosphamide with or without thiotepa. Patients subsequently received a T-cell-depleted allogeneic graft from a HLA-identical family donor (n = 15) or an alternative donor (n = 17). In 4 patients without an allogeneic donor, an unmanipulated autologous graft was used. Infusion-related toxicity due to the labeled antibody was minimal, and no increase in treatment-related mortality due to the radioimmunoconjugate was observed. Day +30 and day +100 mortalities were 3% and 6%, respectively, and after a median follow-up of 18 months treatment-related mortality was 22%. Late renal toxicity was observed in 17% of patients. The relapse rate of 15 patients undergoing transplantation in first CR (complete remission) or second CR was 20%; 21 patients not in remission at the time of transplantation had a 30% relapse rate. (Blood. 2001;98:565-572)

Normal structure of NFKB2, C-REL and BCL-3 gene loci in lymphoproliferative and myeloproliferative disorders

NF-kappaB/rel transcription factors are crucial regulators of development, differentiation and apoptosis of both lymphoid and myeloid lineages. There is increasing evidence for an involvement of NF-kappaB/rel proteins in lymphomagenesis and resistance of lymphoid tumors to the induction of apoptosis. Structural alterations of the NF-kappaB/rel genes NFkappaB2, c-rel and bcl-3 have been shown to result in increased NF-kappaB/rel activity. Because we observed strong constitutive NF-kappaB/rel binding activity in chronic lymphocytic leukemia of the B-cell type (B-CLL) which may contribute to resistance against cytotoxic drugs we studied the genomic organisation of NFkappaB2, c-rel and bcl-3 gene loci in a panel of lymphoproliferative disorders (n=81) with an emphasis on B-CLL (n=47). The method of genomic Southern blotting using cDNAs of the respective genes was used. In spite of the role of NF-kappaB/rel in myeloid maturation there is no data available as to the occurrence of NF-kappaB/rel rearrangements in chronic myeloproliferative syndromes (cMPS). For this reason we included a small panel of cMPS patients (n=16). Southern Blotting revealed a germline configuration of NFkappaB2, c-rel and bcl-3 loci in all NHL and cMPS patients examined. Our results demonstrate that structural alterations of NFkappaB2, c-rel and bcl-3 genes at the Southern Blotting level are rare events that do not contribute to lymphoid or myeloid transformation in the majority of NHL or cMPS patients.

The SH2-containing adapter protein GRB10 interacts with BCR-ABL

Bcr-Abl is an oncogenic tyrosine kinase expressed in tumor cells of CML and a subset of ALL which in its unregulated and activated state is thought to cause cell transformation and leukemia. Bcr-Abl contains several autophosphorylation sites which serve as potential docking sites for SH2-containing signaling molecules. Mutational analysis has indicated that these autophosphorylation sites play a critical role in the transforming capability of Bcr-Abl. It has been shown that the SH2-containing adapter protein Grb2 binds to the autophosphorylation site Tyr(p)177 whereby it couples Bcr-Abl to the Ras pathway. The biological consequences of this interaction, however, are presently unclear. A Tyr177-mutated Bcr-Abl which lacks the ability to interact with the Grb2-SH2 domain still transforms myeloid cells and generates tumors in nude mice. We performed a yeast two-hybrid screen to identify signaling proteins which bind to distinct Bcr-Abl autophosphorylation sites. Autophosphorylation of Bcr-Abl in yeast was accomplished by using the DNA binding protein LexA which permits dimerization and crossphosphorylation of the fused bait. Using a LexA-Bcr-Abl full length fusion protein as bait, we identified several SH2-containing proteins. Among them we confirmed molecules already shown by others to interact with Bcr-Abl, in vivo, including Grb2, PI-3-kinase and Crk indicating that dimerization in yeast leads to autophosphorylation of tyrosine residues crucial for Bcr-Abl signaling in vivo. More importantly, we identified the SH2-containing protein Grb10 as a new binding partner for Bcr-Abl. This binding occurs in a phosphotyrosine-dependent manner at Bcr sites of Bcr-Abl. Both Abl and Bcr alone, as well as a kinase-defective Bcr-Abl, failed to interact with Grb10 in yeast. Mutational analysis uncovered a new SH2 binding site in Bcr-Abl located between Bcr aa242-446, which is different from the Grb2 binding site. Binding could be demonstrated in vitro and also in vivo as shown by co-immunoprecipitation analysis in CML cells. Using a temperature sensitive Bcr-Abl stably overexpressed in hematopoetic cells, we demonstrated that complex formation of Grb10 with Bcr-Abl was kinase activation-dependent in vivo. Notably, a Bcr-Abl mutant protein (Bcr/1-242-Abl) which lacks the ability to interact with Grb10 partially alleviated IL-3 dependence of Ba/F3 cells, indicating that the Grb10/Bcr-Abl interaction is important for Bcr-Abl-induced IL-3 independence of Ba/F3 cells. In addition, the Bcr/1-242-Abl mutant has a reduced capacity to induce focus formation in fibroblasts.

Concomitant manifestation of systemic lupus erythematosus and low-grade non-Hodgkin's lymphoma

We describe a patient presenting with systemic lupus erythematosus (SLE) and concomitant low-grade (Ig) non-Hodgkin's lymphoma of the B cell type (B-NHL). Although the association of autoimmune disorder and lymphoma is well conceived, there is only scarce information available as to the simultaneous occurrence of both disease conditions in one patient. As in this patient diagnosis of Ig B-NHL was also based on the detection of a monoclonal population of CD5+ B lymphocytes, and given that the polyclonal expansion of CD5+ B cells has been previously reported in rheumatoid arthritis (RA), Sjogren's syndrome (SS) and single cases of SLE, the observations we made in this patient led us to discuss the role of the CD5+ population in the development of rheumatic disorders and concomitant lymphoid malignancy. Moreover, since impaired production rates of interleukin 3 (IL-3) and interleukin 4 (IL-4) have been associated with an abnormal expansion of CD5, lymphoma cells and seeing that soluble interleukin 2 receptor (sIL-2R) serum levels were found to be positively correlated with disease activity both in SLE and Ig B-NHL, these parameters were investigated and related to the patient's disease state throughout the entire clinical observation period.

Construction of a novel bifunctional biogenic amine receptor by two point mutations of the H2-histamine receptor

BACKGROUND

H2-histamine receptors mediate a wide range of physiological functions extending from stimulation of gastric acid secretion to induction of human promyelocyte differentiation. We have previously cloned the H2-histamine receptor gene and noted that only three amino acids on the receptor were sufficient to define its specificity and selectivity. Despite only modest overall amino acid homology (34% amino acid identity and 57.5% similarity) between the H2-histamine receptor and the receptor for another monoamine, the beta 2-adrenergic receptor, there is remarkable similarity at their critical ligand binding sites. We hypothesized that, if the specificity and selectivity of both receptors are invested in just three amino acids, it should be possible to convert one of the receptors into one that recognizes the ligand of the other by simple mutations at only one or two sites.

MATERIAL AND METHODS

We explored the effect of two single mutations in the fifth transmembrane domain of the H2-histamine receptor, which encompasses the sites that determine H2 selectivity. The canine H2 receptor gene was mutated at Asp186 and Gly187 (Asp186 to Ala186 and Gly187 to Ser187) by oligonuceotide directed mutagenesis. The coding region of both the wild-type and mutated H2 receptors was subcloned into the eukaryotic expression vector, CMVneo, and stably transfected into Hepa cells and L cells. The biological activity of histamine and epinephrine on the expressed receptor was examined by measurement of cellular cAMP production and inositol trisphosphate formation.

RESULTS

Hepa cells transfected with the Ala186-Ser187 mutant H2 receptor demonstrated a biphasic rise in cAMP in response to epinephrine with an early phase (ED50 approximately 10(-11) M) that could be inhibited by both propranolol and cimetidine. Epinephrine also induced IP3 generation in the same cells, a biological response that is characteristic of activation of the wild-type H2 but not of the beta-adrenergic receptor. L cells transfected with the Ala186-Ser187 mutant H2 receptor also responded to epinephrine in a cimetidine and propranolol inhibitable manner.

CONCLUSIONS

We converted the H2-histamine receptor into a bifunctional one that has characteristics of both histamine and adrenergic receptors by two simple mutations. These results support the hypothesis that ligand specificity is determined by only a few key points on a receptor regardless of the structure of the remainder of the molecule. Our studies have important implications on the design of pharmacological agents targeted for action at physiological receptors.

Molecular cloning of a novel melanocortin receptor

Using the technique of the polymerase chain reaction primed with oligonucleotides based on the homologous transmembrane regions of seven transmembrane G protein-linked receptors, we isolated three full-length human genes that encode a novel subgroup of this receptor family. Recently, two of these receptors were identified as specific for alpha-melanocyte-stimulating hormone (alpha-MSH) and adrenocorticotropic hormone. We report the molecular cloning and pharmacologic characterization of a third member of this subgroup. The gene for this receptor encodes a protein of 361 amino acids in length. Its pharmacology characterizes it as an MSH receptor specific to the heptapeptide core common to adrenocorticotropic hormone and alpha-, beta-, and gamma-MSH. By Northern blot hybridization and polymerase chain reaction, it is expressed in brain, placental, and gut tissues but not in melanoma cells or in the adrenal gland. These findings may yield insight into the physiology of peptides derived from pro-opiomelanocortin post-translational processing.

Molecular basis for the interaction of histamine with the histamine H2 receptor

We undertook these studies to characterize the molecular basis of the interaction of histamine with the H2 receptor. Key areas of homology in the structures of the histamine H2 and beta 2 adrenergic receptor suggested specific transmembrane amino acids that might be important for binding of histamine. A third transmembrane aspartic acid of the histamine receptor (Asp98), thought to serve as a counter anion that interacts with the cationic amine moiety of histamine, was mutated to Asn98, and the mutated receptor was expressed in Hepa cells. Removal of the negatively charged amino acid abolished both binding of the H2 receptor antagonist [methyl-3H]tiotidine and histamine stimulated increases in cellular cAMP content. Mutation of a fifth transmembrane aspartic acid (Asp186) to Ala186 or Asn186 by itself or in conjunction with mutation of another fifth transmembrane amino acid (Thr190 to Ala190) resulted in a loss of [methyl-3H] tiotidine binding, although the generation of cAMP in response to histamine was maintained. The histamine receptor with only a Thr190 to Ala190 or Cys190 mutation retained the ability to bind [methyl-3H]tiotidine, but both the affinity and efficacy of binding were reduced. These data lead us to propose a model for histamine binding in which Asp98 is essential for histamine binding and action, Asp186 defines H2 selectivity, and Thr190 is important in establishing the kinetics of histamine binding, but is not essential for H2 selectivity.