Tumor-selective distribution of an active metabolite of the 9-aminoanthracycline amrubicin

Novel Anthracycline Utorubicin for Cancer Therapy

Novel anticancer compounds and their precision delivery systems are actively developed to create potent and well-tolerated anticancer therapeutics. Here, we report the synthesis of a novel anthracycline, Utorubicin (UTO), and its preclinical development as an anticancer payload for nanocarriers. Free UTO was significantly more toxic to cultured tumor cell lines than the clinically used anthracycline, doxorubicin. Nanoformulated UTO, encapsulated in polymeric nanovesicles (polymersomes, PS), reduced the viability of cultured malignant cells and this effect was potentiated by functionalization with a tumor-penetrating peptide (TPP). Systemic peptide-guided PS showed preferential accumulation in triple-negative breast tumor xenografts implanted in mice. At the same systemic UTO dose, the highest UTO accumulation in tumor tissue was seen for the TPP-targeted PS, followed by nontargeted PS, and free doxorubicin. Our study suggests potential applications for UTO in the treatment of malignant diseases and encourages further preclinical and clinical studies on UTO as a nanocarrier payload for precision cancer therapy.

Novel Anthracycline Utorubicin for Cancer Therapy

Novel anticancer compounds and their precision delivery systems are actively developed to create potent and well-tolerated anticancer therapeutics. Here, we report the synthesis of a novel anthracycline, Utorubicin (UTO), and its preclinical development as an anticancer payload for nanocarriers. Free UTO was significantly more toxic to cultured tumor cell lines than the clinically used anthracycline, doxorubicin. Nanoformulated UTO, encapsulated in polymeric nanovesicles (polymersomes, PS), reduced the viability of cultured malignant cells and this effect was potentiated by functionalization with a tumor-penetrating peptide (TPP). Systemic peptide-guided PS showed preferential accumulation in triple-negative breast tumor xenografts implanted in mice. At the same systemic UTO dose, the highest UTO accumulation in tumor tissue was seen for the TPP-targeted PS, followed by nontargeted PS, and free doxorubicin. Our study suggests potential applications for UTO in the treatment of malignant diseases and encourages further preclinical and clinical studies on UTO as a nanocarrier payload for precision cancer therapy.

Phase II study of amrubicin plus erlotinib in previously treated, advanced non-small cell lung cancer with wild-type epidermal growth factor receptor (TORG1320)

Background Amrubicin (AMR) is a completely synthetic 9-aminoanthracycline and clinically active against non-small cell lung cancer (NSCLC). We conducted a phase I study of AMR and erlotinib (ERL) combination therapy in previously treated patients with advanced NSCLC and have already reported the safety and effectiveness. Methods We conducted a multi-center, single-arm phase II trial to evaluate the efficacy of AMR and ERL combination therapy in patients with previously treated, advanced NSCLC harboring wild-type EGFR, PS 0-1 and < 75 years of age. Patients were treated at 3-week intervals with AMR plus ERL. The primary endpoint was the PFS, and the secondary endpoints were the response rate (RR), disease control rate (DCR), overall survival (OS) and toxicity. The trough ERL concentration (C_trough) was measured as an exploratory study to analyze the relationship between the efficacy/safety and pharmacokinetics. Results From June 2013 to July 2016, 25 patients were enrolled in this trial. The PFS according to the central test was 3.6 months (95% confidence interval 2.1-5.1). The RR and DCR were 24.0% and 64.0%, respectively. We had no treatment-related deaths in this study. Conclusions The PFS of AMR and ERL combination therapy was superior to that of AMR monotherapy in the historical setting, but the primary endpoint was not met in this trial. In our study, the pharmacokinetic analysis showed that the C_trough of ERL was elevated with combination therapy. This combination therapy might be a viable treatment for previously treated NSCLC patients without a driver oncogene mutation. Clinical trial information UMIN 000010582.

Systemic treatment in advanced soft tissue sarcoma: what is standard, what is new

For metastatic soft tissue sarcoma (STS) patients not eligible for surgery, systemic treatments, including standard chemotherapy and newer biological compounds, still play the most relevant role in the management of the disease. An anthracycline and alkylating agent combination has formed the cornerstone of chemotherapy in STS for more than 30 years, with its value over that of administration of anthracycline as a single agent still being debated. Efforts have been made to improve the activity and minimise the toxicity of the combination, as well as to explore the upfront efficacy of agents known to be active in sarcoma and to develop new biological compounds. Nevertheless, beyond the first line, evidence for medical treatment in STS is less robust and all the more driven by histology. Thus, the introduction of kinases and small molecule inhibitors in the treatment armamentarium for STS is a major achievement in this setting. Preliminary data on immunotherapy are also available and discussed in this review.

The ATS/ERS/JRS/ALAT statement "IPF by HRCT" could predict acute exacerbation of interstitial lung disease in non-small cell lung cancer

INTRODUCTION

Patients with non-small cell lung cancer (NSCLC) and interstitial lung disease (ILD) are at high risk of acute exacerbation of ILD (AE-ILD) when treated with systemic chemotherapy. Standard treatment for NSCLC complicated by ILD has not been established.

PURPOSE AND METHODS

To examine whether the type of ILD categorized by the official ATS/ERS/JRS/ALAT statement as "idiopathic pulmonary fibrosis (IPF) by high-resolution computed tomography (HRCT)" could predict chemotherapy-induced AE-ILD in NSCLC patients with ILD, we retrospectively reviewed all patients with NSCLC complicated by ILD who had received chemotherapy at our institute from January 2007 until December 2013. Patients' characteristics, pathology and clinical staging of lung cancer, chemotherapy, type of ILD and AE-ILD during chemotherapy were evaluated. ILD was classified according to the statement as follows: usual interstitial pneumonia (UIP), possible UIP, and inconsistent with a UIP pattern.

RESULTS

A total of 46 patients had pre-existing ILD and received chemotherapy. The mean age was 73 years (range 46-83 years). Fifteen (32.6%) of 46 patients with ILD developed chemotherapy-induced AE-ILD, which was seen more frequently in patients with ILD with a UIP pattern or possible UIP pattern than in patients with a pattern inconsistent with UIP (80% versus 9.7%, p&lt;0.001). Multivariate analyses including age, sex, performance status and radiographic patterns of ILD showed that the presence of a UIP or possible UIP pattern was an independent risk factor for chemotherapy-induced AE-ILD.

CONCLUSIONS

ILD with a UIP pattern or possible UIP pattern by the classification could be a risk factor for AE-ILD in NSCLC patients with ILD.

The role of anthracyclines in small cell lung cancer

Small cell lung cancer (SCLC) represents the 15% of the totally of lung cancer. The percentage of cases in women is arising due to the differences in smoking patterns; it occurs almost exclusively in smokers and appears to be most common in heavy smokers. The stage of disease at presentation is the most important prognostic factor in patients with SCLC; for patients with extended stage disease, the median survival is around 10 months, and the five-year survival rate is 1 to 2 percent. The standard regimen for patients with extensive disease is cisplatin based chemotherapy. Second line chemotherapy is generally less effective than the initial treatment but it can provide significant palliation for many patients. We make a review here of the different options of second line chemotherapy and the role of anthracyclines in it.

Relapsed small cell lung cancer: treatment options and latest developments

According to recent analyses, there was a modest yet significant improvement in median survival time and 5-year survival rate of limited stage small cell lung cancer (SCLC) in North America, Europe, Japan and other countries over the last 30 years. The median survival time of limited stage SCLC is 15-20 months and 5-year survival rate is 15% or less. In terms of extensive stage SCLC, a median survival time of 9.4-12.8 months and 2-year survival of 5.2-19.5% are still disappointing. Despite being highly sensitive to first-line chemotherapy and radiotherapy treatments, most patients with SCLC experience relapse within 2 years and die from systemic metastasis. While several clinical trials of cytotoxic chemotherapies and molecular targeting agents have been investigated in the treatment of relapsed SCLC, none showed a significant clinical activity to be able to exceed topotecan as second-line chemotherapy. There are problematic issues to address for relapsed SCLC, such as standardizing the treatment for third-line chemotherapy. Topotecan alone was the first approved therapy for second-line treatment for relapsed SCLC. Amrubicin is a promising drug and a variety of trials evaluating its efficacy have been carried out. Amrubicin has shown superiority to topotecan in a Japanese population, but was not superior in a study of western patients. There are some controversial issues for relapsed SCLC, such as treatment for older patients, third-line chemotherapy and efficacy of molecular targeting therapy. This article reviews current standard treatment, recent clinical trials and other topics on relapsed SCLC.

Phase III Study Comparing Amrubicin Plus Cisplatin With Irinotecan Plus Cisplatin in the Treatment of Extensive-Disease Small-Cell Lung Cancer: JCOG 0509

Purpose

This randomized phase III trial was conducted to confirm noninferiority of amrubicin plus cisplatin (AP) compared with irinotecan plus cisplatin (IP) in terms of overall survival (OS) in chemotherapy-naive patients with extensive-disease (ED) small-cell lung cancer (SCLC).

Patients and Methods

Chemotherapy-naive patients with ED-SCLC were randomly assigned to receive IP, composed of irinotecan 60 mg/m2 on days 1, 8, and 15 and cisplatin 60 mg/m2 on day 1 every 4 weeks, or AP, composed of amrubicin 40 mg/m2 on days 1, 2, and 3 and cisplatin 60 mg/m2 on day 1 every 3 weeks.

Results

A total of 284 patients were randomly assigned to IP (n = 142) and AP (n = 142) arms. The point estimate of OS hazard ratio (HR) for AP to IP in the second interim analysis exceeded the noninferior margin (HR, 1.31), resulting in early publication because of futility. In updated analysis, median survival time was 17.7 (IP) versus 15.0 months (AP; HR, 1.43; 95% CI, 1.10 to 1.85), median progression-free survival was 5.6 (IP) versus 5.1 months (AP; HR, 1.42; 95% CI, 1.16 to 1.73), and response rate was 72.3% (IP) versus 77.9% (AP; P = .33). Adverse events observed in IP and AP arms were grade 4 neutropenia (22.5% v 79.3%), grade 3 to 4 febrile neutropenia (10.6% v 32.1%), and grade 3 to 4 diarrhea (7.7% v 1.4%).

Conclusion

AP proved inferior to IP in this trial, perhaps because the efficacy of amrubicin as a salvage therapy was differentially beneficial to IP. IP remains the standard treatment for extensive-stage SCLC in Japan.

C609T Polymorphism of NADPH Quinone Oxidoreductase 1 Correlates Clinical Hematological Toxicities in Lung Cancer Patients Treated with Amrubicin

Background:

Amrubicin hydrochloride (AMR) is a key agent for lung cancer. NADPH quinone oxidoreductase 1 (NQO1) metabolizes the quinone structures contained in both amrubicin (AMR) and amrubicinol (AMR-OH). We hypothesized that NQO1 C609T polymorphism may affect AMR-related pharmacokinetics and clinical outcomes.

Methods:

Patients received AMR doses of 30 or 40 mg/m²/day on days 1–3. Plasma sampling was performed 24 hours after the first and third AMR injections. Concentrations of AMR and AMR-OH were determined by HPLC and the NQO1 C609T polymorphism was assayed by RT-PCR.

Results:

A total of 35 patients were enrolled. At a dose of 40 mg/m², the T/T genotype exhibited a tendency toward a relationship with decrease concentrations of AMR-OH on days 2 and 4. The genotype also showed a significant decrease of hematological toxicities (P < 0.05).

Conclusions:

NQO1 C609T polymorphism had a tendency of correlation with the plasma concentrations of AMR-OH, and thereby had significant correlations with hematologic toxicities.

Risk factors for predicting severe neutropenia induced by amrubicin in patients with advanced lung cancer

BACKGROUND

Neutropenia is one of the most frequent and dose-limiting toxicities in amrubicin (AMR) therapy. However, the predictive factors for the development of severe neutropenia in AMR therapy remain unknown.

METHODS

The subjects were 61 advanced lung cancer patients treated with AMR monotherapy. All data were retrospectively collected from the electronic medical record system. A stepwise logistic regression analysis was performed to identify risk factors for grade 3-4 neutropenia.

RESULTS

Of a total 61 patients, 50 were male and 11 were female. The median dose of AMR was 35.0 mg/m(2). The incidence of grade 3-4 neutropenia during the first course was 62%. In multivariate analysis, female gender (OR = 6.68; 95% CI 1.01-134.15; p = 0.049), higher AMR doses (40 mg/m(2) or more) (OR = 5.98; 95% CI 1.77-23.74; p = 0.003), and lower hematocrit values (OR = 2.04 per 5% decrease; 95% CI 1.04-4.38; p = 0.036) were significantly associated with severe neutropenia induced by AMR.

CONCLUSION

The present results suggest that female gender, higher doses of AMR, and lower baseline hematocrit values are predictive factors associated with severe neutropenia induced by AMR in patients with advanced lung cancer. Patients who have these predictive factors should be monitored carefully and considered for early granulocyte colony-stimulating factor support.

Pharmacokinetic characterization of amrubicin cardiac safety in an ex vivo human myocardial strip model. II. Amrubicin shows metabolic advantages over doxorubicin and epirubicin

Anthracycline-related cardiotoxicity correlates with cardiac anthracycline accumulation and bioactivation to secondary alcohol metabolites or reactive oxygen species (ROS), such as superoxide anion (O₂·⁻) and hydrogen peroxide H₂O₂). We reported that in an ex vivo human myocardial strip model, 3 or 10 μM amrubicin [(7S,9S)-9-acetyl-9-amino-7-[(2-deoxy-β-D-erythro-pentopyranosyl)oxy]-7,8,9,10-tetrahydro-6,11-dihydroxy-5,12-napthacenedione hydrochloride] accumulated to a lower level compared with equimolar doxorubicin or epirubicin (J Pharmacol Exp Ther 341:464-473, 2012). We have characterized how amrubicin converted to ROS or secondary alcohol metabolite in comparison with doxorubicin (that formed both toxic species) or epirubicin (that lacked ROS formation and showed an impaired conversion to alcohol metabolite). Amrubicin and doxorubicin partitioned to mitochondria and caused similar elevations of H₂O₂, but the mechanisms of H₂O₂ formation were different. Amrubicin produced H₂O₂ by enzymatic reduction-oxidation of its quinone moiety, whereas doxorubicin acted by inducing mitochondrial uncoupling. Moreover, mitochondrial aconitase assays showed that 3 μM amrubicin caused an O₂·⁻-dependent reversible inactivation, whereas doxorubicin always caused an irreversible inactivation. Low concentrations of amrubicin therefore proved similar to epirubicin in sparing mitochondrial aconitase from irreversible inactivation. The soluble fraction of human myocardial strips converted doxorubicin and epirubicin to secondary alcohol metabolites that irreversibly inactivated cytoplasmic aconitase; in contrast, strips exposed to amrubicin failed to generate its secondary alcohol metabolite, amrubicinol, and only occasionally exhibited an irreversible inactivation of cytoplasmic aconitase. This was caused by competing pathways that favored formation and complete or near-to-complete elimination of 9-deaminoamrubicinol. These results characterize amrubicin metabolic advantages over doxorubicin and epirubicin, which may correlate with amrubicin cardiac safety in preclinical or clinical settings.

C609T polymorphism of NAD(P)H quinone oxidoreductase 1 as a predictive biomarker for response to amrubicin

INTRODUCTION

Amrubicin is a promising agent in the treatment of lung cancer, but predictive biomarkers have not yet been described. NAD(P)H:quinone oxidoreductase 1 (NQO1) is an enzyme known to metabolize amrubicinol, the active metabolite of amrubicin, to an inactive compound. We examined the relationship between NQO1 and amrubicinol cytotoxicity.

METHODS

Gene and protein expression of NQO1, amrubicinol cytotoxicity, and C609T single-nucleotide polymorphism of NQO1 were evaluated in 29 lung cancer cell lines: 14 small cell lung cancer (SCLC) and 15 non-SCLC (NSCLC). The involvement of NQO1 in amrubicinol cytotoxicity was evaluated by small interfering RNA against NQO1.

RESULTS

A significant inverse relationship between both gene and protein expression of NQO1 and amrubicinol cytotoxicity was found in all cell lines. Treatment with NQO1 small interfering RNA increased amrubicinol cytotoxicity and decreased NQO1 expression in both NSCLC and SCLC cells. Furthermore, cell lines genotyped homozygous for the 609T allele showed significantly lower NQO1 protein expression and higher sensitivity for amrubicinol than those with the other genotypes in both NSCLC and SCLC cells.

CONCLUSIONS

NQO1 expression is one of the major determinants for amrubicinol cytotoxicity, and C609T single-nucleotide polymorphism of NQO1 could be a predictive biomarker for response to amrubicin treatment.

Randomised phase II study of amrubicin as single agent or in combination with cisplatin versus cisplatin etoposide as first-line treatment in patients with extensive stage small cell lung cancer - EORTC 08062

PURPOSE

The EORTC 08062 phase II randomised trial investigated the activity and safety of single agent amrubicin, cisplatin combined with amrubicin, and cisplatin combined with etoposide as first line treatment in extensive disease (ED) small cell lung cancer (SCLC).

PATIENTS AND METHODS

Eligible patients with previously untreated ED-SCLC, WHO performance status (PS) 0-2 and measurable disease were randomised to 3 weekly cycles of either amrubicin alone 45mg/m(2) i.v. day(d) 1-3 (A), cisplatin 60mg/m(2) i.v. d1 and amrubicin 40mg/m(2) i.v. d1-3 (PA), or cisplatin 75mg/m(2) i.v. d1 and etoposide 100mg/m(2) d1, d2-3 i.v./po (PE). The primary end-point was overall response rate (ORR) as assessed by local investigators (RECIST1.0 criteria). Secondary end-points were treatment toxicity, progression-free survival and overall survival.

RESULTS

The number of randomised/eligible patients who started treatment was 33/28 in A, 33/30 in PA and 33/30 in PE, respectively. Grade (G) ⩾3 haematological toxicity in A, PA and PE was neutropenia (73%, 73%, 69%); thrombocytopenia (17%, 15%, 9.4%), anaemia (10%, 15%, 3.1%) and febrile neutropenia (13%, 18%, 6%). Early deaths, including treatment related, occurred in 1, 3 and 3 patients in A, PA and PE arms, respectively. Cardiac toxicity did not differ among the 3 arms. Out of 88 eligible patients who started treatment, ORR was 61%, (90% 1-sided confidence intervals [CI] 47-100%), 77% (CI 64-100%) and 63%, (CI 50-100%) for A, PA and PE respectively.

CONCLUSION

All regimens were active and PA met the criteria for further investigation, despite slightly higher haematological toxicity.

Review of the management of relapsed small-cell lung cancer with amrubicin hydrochloride

Lung cancer is the leading cause of cancer death, and approximately 15% of all lung cancer patients have small-cell lung cancer (SCLC). Although second-line chemotherapy can produce tumor regression, the prognosis is poor. Amrubicin hydrochloride (AMR) is a synthetic anthracycline anticancer agent and a potent topoisomerase II inhibitor. Here, we discuss the features of SCLC, the chemistry, pharmacokinetics, and pharmacodynamics of AMR, the results of in vitro and in vivo studies, and the efficacy and safety of AMR monotherapy and combination therapy in clinical trials. With its predictable and manageable toxicities, AMR is one of the most attractive agents for the treatment of chemotherapy-sensitive and -refractory relapsed SCLC. Numerous studies are ongoing to define the applicability of AMR therapy for patients with SCLC. These clinical trials, including phase III studies, will clarify the status of AMR in the treatment of SCLC.

Recent Pharmacological Advances: Focus on Small-cell Lung Cancer

Small cell lung cancer (SCLC) represents approximately 15% of all lung cancers, and is the most aggressive form of lung cancer. Left untreated, the time from diagnosis to death is 2–3 months. With current treatment, expected survival is 7–20 months, depending on the stage of disease. A new drug, amrubicin, is approved in Japan for lung cancer and has demonstrated efficacy in U.S. and European phase II trials of SCLC patients with either untreated disease or relapsed refractory illness. In a phase II study of amrubicin in previously untreated patients, response rates reached 75% with a median survival time of almost 1 year. Amrubicin is a fully synthetic 9-aminoanthracycline, and an analog of doxorubicin and epirubicin. The major mechanism of action of amrubicin is inhibition of topoisomerase II. Unlike doxorubicin, however, it exhibits little or no cardiotoxicity in clinical studies and preclinical models. In preclinical rodent tumor models, it is selectively distributed to tumour tissue and is not detected in the heart when compared with doxorubicin, which is distributed equivalently to these sites. The primary metabolite of amrubicin, amrubicinol, is up to 100 times more cytotoxic in vitro than the parent compound. This review describes the mechanisms of action of amrubicin as well as clinical studies which demonstrate the potential of this drug in future SCLC treatment. The review also puts forward hypothetical considerations for the use of other drugs such as lenalidomide, an immunomodulatory drug acting on multiple signalling pathways, or histone deacetylase inhibitors, in combination with amrubicin in SCLC.

Efficacy of combination treatment and influence of schedule with irinotecan and amrubicin in human lung carcinoma cells in vivo and in vitro

The aim of this study was to elucidate the efficacy of combination therapy with irinotecan and amrubicin for lung cancer and the influence of administration schedule in a xenograft mouse model and human cancer cell culture. We investigated the antitumor activity of irinotecan and amrubicin on human small cell lung cancer cell line LX-1 inoculated in mice in vivo and the cytotoxic effect of SN-38 and amrubicinol on human lung cancer cell lines A549 and PC-6 in vitro. Combined administration of irinotecan and amrubicin in divided doses inhibited tumor growth by approximately 90%, with complete recovery observed in one case. Furthermore, combined administration in divided doses induced little loss of body weight. Combination index analysis revealed that the cell growth inhibitory effect of SN-38 combined with amrubicinol was additive, regardless of schedule or cell line. The effect of combination treatment with SN-38 and amrubicinol on cell cycle was investigated. Cell cycle showed arrest at both the S and G2/M phases. The results indicate that combination therapy with irinotecan and amrubicin can be expected to yield improved outcomes, including less toxicity, especially with divided administration.

Phase II trial of amrubicin for second-line treatment of advanced non-small cell lung cancer: results of the West Japan Thoracic Oncology Group trial (WJTOG0401)

BACKGROUND

Amrubicin is a synthetic anthracycline drug that is a potent inhibitor of topoisomerase II. We have performed a multicenter phase II trial to evaluate the efficacy and safety of amrubicin for patients with previously treated non-small cell lung cancer (NSCLC).

METHODS

Patients with advanced NSCLC who experienced disease recurrence after one platinum-based chemotherapy regimen were eligible for enrollment in the study. Amrubicin was administered by intravenous injection at a dose of 40 mg/m2 on 3 consecutive days every 3 weeks.

RESULTS

Sixty-one enrolled patients received a total of 192 treatment cycles (median, 2; range, 1-15). Response was as follows: complete response, 0; partial response, seven (11.5%); stable disease, 20 (32.8%); and progressive disease, 34 (55.7%). Median progression-free survival was 1.8 months, whereas median overall survival was 8.5 months, and the 1-year survival rate was 32%. Hematologic toxicities of grade 3 or 4 included neutropenia (82.0%), leukopenia (73.8%), thrombocytopenia (24.6%), and anemia (27.9%). Febrile neutropenia occurred in 18 patients (29.5%). One treatment-related death due to infection was observed. Nonhematologic toxicities were mild.

CONCLUSIONS

Amrubicin is a possible alternative for second-line treatment of advanced NSCLC, although a relevant hematological toxicity is significant, especially with a febrile neutropenia.

Plasma concentration of amrubicinol in plateau phase in patients treated for 3 days with amrubicin is correlated with hematological toxicities

Amrubicinol (AMR-OH) is an active metabolite of amrubicin (AMR), a novel synthetic 9-aminoanthracycline derivative. The time-concentration profile of AMR-OH exhibits a continuous long plateau slope in the terminal phase. To determine the relationships between the steady-state plasma concentration of AMR-OH and treatment effects and toxicities associated with AMR therapy, we carried out a pharmacokinetic/pharmacodynamic study in patients treated with AMR alone or the combination of AMR+cisplatin (CDDP). AMR was given at a dose of 30 or 40 mg/m(2) on days 1-3. Plasma samples were collected 24 h after the third injection (day 4). Plasma concentrations of AMR-OH or total CDDP were determined by a high-performance liquid chromatography or an atomic absorption spectrometry. Percent change in neutrophil count (dANC) and the plasma concentration of AMR-OH were evaluated using a sigmoid E(max) model. A total of 35 patients were enrolled. Significant relationships were observed between AMR-OH on day 4 and the toxicity grades of leukopenia, neutropenia, and anemia (P=0.018, P=0.012, and P=0.025, respectively). Thrombocytopenia grade exhibited a tendency toward relationship with AMR-OH on day 4 (P=0.081). The plasma concentration of AMR-OH on day 4 was positively correlated with dANC in the group of all patients, as well as in patients treated with AMR alone and in patients coadministered with CDDP. In conclusion, the plasma concentration of AMR-OH on day 4 was correlated with hematological toxicities in patients treated with AMR. The assessment of plasma concentration of AMR-OH at one timepoint might enable the prediction of hematological toxicities.

Simple and sensitive HPLC method for determination of amrubicin and amrubicinol in human plasma: application to a clinical pharmacokinetic study

A simple and sensitive high-performance liquid chromatographic (HPLC) method was developed for determination of amrubicin and its metabolite amrubicinol in human plasma. After protein precipitation with methanol without evaporation procedure, large volume samples were injected and separated by two monolithic columns with a guard column. The mobile phase consisted of tetrahydrofuran-dioxane-water (containing 2.3 mM acetic acid and 4 mM sodium 1-octanesulfonate; 2:6:15, v/v/v). Wavelengths of fluorescence detection were set at 480 nm for excitation and 550 nm for detection. Under these conditions, linearity was confirmed in the 2.5-5000 ng/mL concentration range of both compounds. The intra- and inter-day precision and intra- and inter-day accuracy for both compounds were less than 10%. The method was successfully applied to a clinical pharmacokinetic study of amrubicin and amrubicinol in cancer patients.

Retrospective analysis of efficacy and safety of amrubicin in refractory and relapsed small-cell lung cancer

BACKGROUND

Amrubicin, a totally synthetic 9-aminoanthracycline, was evaluated retrospectively for the treatment of refractory and relapsed small-cell lung cancer (SCLC).

METHODS

Retrospective analysis was performed in 32 patients. Amrubicin was infused over 5 min on days 1-3, with courses repeated at 3- or 4-week intervals. Amrubicin was given at a dose of 45 mg/m(2) per day, 40 mg/m(2) per day, 35 mg/m(2) per day, 30 mg/m(2) per day, or 25 mg/m(2) per day depending on medical conditions (patients' age and performance status [PS]), and the dose was modulated according to myelosuppression.

RESULTS

The median number of treatment cycles was 3 (range, 1-6). Seventeen patients (53.1%) had a partial response. Median progression-free survival time for all patients was 96 days, and median survival time was 166 days. Grade 3 or 4 hematologic toxicities comprised neutropenia (78.1%), anemia (65.6%), and thrombocytopenia (50.0%). Febrile neutropenia was observed in 8 patients (25.0%). Nonhematologic toxicities were mild. Treatment-related death was observed in 1 patient.

CONCLUSION

Treatment with amrubicin appeared effective in SCLC patients previously treated with chemotherapy, although it was not necessarily safe, because of myelosuppression. Further research is warranted to investigate amrubicin treatment for patients with SCLC.

Characterization of the enzymes involved in thein vitrometabolism of amrubicin hydrochloride

The in vitro metabolism of amrubicin by rat and human liver microsomes and cytosol was examined. The main metabolic routes in both species were reductive deglycosylation and carbonyl group reduction in the side-chain. In vitro metabolism of amrubicinol by rat and human liver microsomes and cytosol was also examined and the main metabolic route of this active metabolite was reductive deglycosylation. Metabolism of amrubicin in human liver microsomes was inhibited by TlCl(3) and that in human liver cytosol was inhibited by dicumarol and quercetin. Generation of amrubicinol was inhibited only by quercetin. The results indicate that metabolism of amrubicin is mediated by NADPH-cytochrome P450 reductase, NADPH:quinone oxidoreductase and carbonyl reductase. In addition, generation of amrubicinol is mediated by carbonyl reductase. Metabolism of amrubicinol in human liver microsomes was inhibited by TlCl(3) and that in human liver cytosol was inhibited by dicumarol. The results indicate that metabolism of amrubicinol is mediated by NADPH-cytochrome P450 reductase and NADPH:quinone oxidoreductase. To investigate the influence of cisplatin on the metabolism of amrubicin and amrubicinol, human liver microsomes and cytosol were pre-incubated with cisplatin. This did not change the rates of amrubicin and amrubicinol metabolism in either human liver microsomes or cytosol.

Dose escalation study of amrubicin in combination with fixed-dose irinotecan in patients with extensive small-cell lung cancer

BACKGROUND

The combination of amrubicin (Am) and irinotecan (CPT) shows appreciable activity against small-cell lung cancer (SCLC) in vitro.

PATIENTS AND METHODS

We conducted a dose escalation study of Am in combination with CPT to determine the qualitative and quantitative toxicities and efficacy against extensive (ED) SCLC.

RESULTS

Thirteen previously untreated patients with ED-SCLC were treated with CPT at 60 mg/m(2) on day 1 and dose-escalated Am on days 1-3 with prophylactic granulocyte colony-stimulating factor subcutaneously on days 5-9 every 2-3 weeks. At level 3 (40 mg/m(2)/day Am), 3 of 4 registered patients experienced dose-limiting toxicity such as grade 4 neutropenic fever, and therefore, this was defined as the maximum tolerated dose. A total of 31 courses was administered at dose level 2 (35 mg/m(2)/day) in 6 patients, and grade 4 neutropenia was observed during 5 courses (16.1%). Non-hematological toxicities, except 1 course of grade 3 transfusion of red blood cells and 1 course of grade 3 transaminase elevation, were mild. Thus, dose level 2 of Am was recommended for further study. One patient achieved complete remission and 12 achieved partial remission, and the overall response rate was 100%. The median survival time was 17.4 months, and the 1-year survival rate was 76.9%.

CONCLUSIONS

CPT at 60 mg/m(2) on day 1 and Am at 35 mg/m(2)/day on days 1-3 with granulocyte colony-stimulating factor support every 3 weeks is recommended for Japanese patients with ED-SCLC.

Hematological aspects of a novel 9-aminoanthracycline, amrubicin

Our previous study showed that the myelosuppression induced by a single-bolus intravenous injection of amrubicin into mice was more severe, even at half the maximum tolerated dose (MTD), than that induced by adriamycin (ADR) at the MTD, but that the recovery was more rapid than that after ADR. The present study shows that the administration of amrubicin significantly decreased the number of colony-forming units of granulocytes and monocytes (CFU-GM) from day 1, but that the CFU-GM numbers recovered by day 3. In contrast, the administration of ADR induced a continuous decrease in the numbers of CFU-GM until day 10. The early myelosuppression and rapid recovery of white blood cells (WBC) induced by amrubicin may depend upon the early decrease in the number of CFU-GM and the rapid recovery of CFU-GM. These data suggest that the toxic effects on the peripheral blood and bone marrow induced by amrubicin are more reversible and more controllable than those induced by ADR.

Amrubicin, a novel 9-aminoanthracycline, enhances the antitumor activity of chemotherapeutic agents against human cancer cells in vitro and in vivo

Amrubicin, a completely synthetic 9-aminoanthracycline derivative, is an active agent in the treatment of untreated extensive disease-small-cell lung cancer and advanced non-small-cell lung cancer. Amrubicin administered intravenously at 25 mg/kg substantially prevented the growth of five of six human lung cancer xenografts established in athymic nude mice, confirming that amrubicin as a single agent was active in human lung tumors. To survey which antitumor agent available for clinical use produces a synergistic interaction with amrubicin, we examined the effects in combinations with amrubicinol, an active metabolite of amrubicin, of several chemotherapeutic agents in vitro using five human cancer cell lines using the combination index (CI) method of Chou and Talalay. Synergistic effects were obtained on the simultaneous use of amrubicinol with cisplatin, irinotecan, gefitinib and trastuzumab, with CI values after 3 days of exposure being <1. Additive effect was observed with the combination containing vinorelbine with CI values indistinguishable from 1, while the combination of amrubicinol with gemcitabine was antagonistic. All combinations tested in vivo were well tolerated. The combinations of cisplatin, irinotecan, vinorelbine, trastuzumab, tegafur/uracil, and to a lesser extent, gemcitabine with amrubicin caused significant growth inhibition of human tumor xenografts without pronouncedly enhancing body weight loss, compared with treatment using amrubicin alone at the maximum tolerated dose. Growth inhibition of tumors by gefitinib was not antagonized by amrubicin. These results suggest that amrubicin appears to be a possible candidate for combined use with cisplatin, irinotecan, vinorelbine, gemcitabine, tegafur/uracil or trastuzumab.

Amrubicin induces apoptosis in human tumor cells mediated by the activation of caspase-3/7 preceding a loss of mitochondrial membrane potential

Amrubicin, a completely synthetic 9-aminoanthracycline derivative, inhibits cell growth by stabilizing a topoisomerase II-DNA complex. This study was designed to examine the apoptosis induced in human leukemia U937 cells by amrubicin and its active metabolite amrubicinol. Amrubicin, amrubicinol and other antitumor agents, such as daunorubicin and etoposide, induced typical apoptosis with characteristic nuclear morphological change and DNA fragmentation. Measuring the population of sub-G(1) phase cells, it was found that under conditions where cell growth was inhibited by either amrubicin or amrubicinol, U937 cells underwent apoptotic cell death in a dose-dependent manner accompanied by an arrest of the cell cycle at G(2)/M. Furthermore, amrubicin- and amrubicinol-induced apoptosis was mediated by the activation of caspase-3/7, but not caspase-1, preceding a loss of mitochondrial membrane potential. These results indicate that both a reduction in mitochondrial membrane potential and the activation of caspase-3/7 are key events in the apoptosis induced by amrubicin and amrubicinol as well as the other antitumor agents. In addition, studies with oligomycin suggested that the apoptosis induced by amrubicin and amrubicinol involved substantially different pathways from that triggered by daunorubicin and etoposide. Oligomycin blocked the etoposide-induced increase in the number of sub-G(1) phase cells without preventing the activation of caspase-3/7, and had no inhibitory effect on the expansion of the sub-G(1) population in daunorubicin-treated cells, whereas apoptosis-related changes caused by amrubicin and amrubicinol were suppressed in the presence of oligomycin.

Phase I and pharmacologic study of irinotecan and amrubicin in advanced non-small cell lung cancer

PURPOSE

We conducted a Phase I trial of irinotecan (CPT-11), a topoisomerase I inhibitor, combined with amrubicin, a topoisomerase II inhibitor. The aim was to determine the maximum tolerated dose (MTD) of amrubicin combined with a fixed dose of CPT-11 as well as the dose-limiting toxicities (DLT) of this combination in patients with advanced non-small cell lung cancer.

PATIENTS AND METHODS

Eleven patients with stage IIIB or IV disease were treated at 3-week intervals with amrubicin (5-min intravenous injection on days 1-3) plus 60 mg/m2 of CPT-11 (90-min intravenous infusion on days 1 and 8). The starting dose of amrubicin was 25 mg/m2, and it was escalated in 5 mg/m2 increments until the maximum tolerated dose was reached.

RESULTS

The 30 mg/m2 of amrubicin dose was one dose level above the MTD, since three of the five patients experienced DLT during the first cycle of treatment at this dose level. Diarrhea and leukopenia were the DLT, while thrombocytopenia was only a moderate problem. Amrubicin did not affect the pharmacokinetics of CPT-11, SN-38 or SN-38 glucuronide. Except for one patient, the biliary index on day-1 correlated well with the percentage decrease of neutrophils in a sigmoid Emax model. There were five partial responses among 11 patients for an overall response rate of 45%.

CONCLUSION

The combination of amrubicin and CPT-11 seems to be active against non-small cell lung cancer with acceptable toxicity. The recommended dose for Phase II studies is 60 mg/m2 of CPT-11 (days 1 and 8) and 25 mg/m2 of amrubicin (days 1-3) administered every 21 days.

Pharmacokinetics of Amrubicin and Its Active Metabolite Amrubicinol in Lung Cancer Patients

Amrubicin, a synthetic 9-aminoanthracycline agent, was recently approved in Japan for treatment of small-cell lung cancer and non-small-cell lung cancer. Amrubicin is converted enzymatically to the C-13 hydroxy metabolite amrubicinol, which is active and possesses a cytotoxicity 10 to 100 times that of the parent drug. The purpose of this study was to characterize the pharmacokinetics of amrubicin and its active metabolite amrubicinol. Amrubicin was administered on days 1-3 in 16 patients with advanced lung cancer. The pharmacokinetics analysis of amrubicin and amrubicinol was performed by high-performance liquid chromatography. When 45 mg/m amrubicin was administered in a bolus injection once every 24 hours for 3 consecutive days, the areas under the curves (0 to 72 hours) for amrubicin and amrubicinol were 13,490 and 2585 ng . h/mL, respectively. The apparent total clearance (CLapp) of amrubicin was 15.4 L/h. The area-under-the-curve ratio of amrubicinol to amrubicin was 15.1 +/- 4.6% (mean +/- SD) at doses ranging from 30 to 45 mg/m. Interindividual variability in the enzymatic conversion of amrubicin to amrubicinol was small. In contrast, a large interindividual variability in the CLapp of amrubicin was observed (CV = 49.8%). The areas under the curves of amrubicin and amrubicinol seemed to be associated with the severity of hematologic toxicities. There is a possibility that monitoring of the plasma concentrations of amrubicin and amrubicinol may provide an efficient tool for establishing the optimal dosage of amrubicin in each patient.

Phase I and pharmacokinetic study of amrubicin, a synthetic 9-aminoanthracycline, in patients with refractory or relapsed lung cancer

Amrubicin is a novel synthetic 9-aminoanthracycline derivative and is converted enzymatically to its C-13 hydroxy metabolite, amrubicinol, whose cytotoxic activity is 10-100 times that of amrubicin. We aimed to determine the maximum tolerated dose (MTD) of amrubicin and to characterize the pharmacokinetics of amrubicin and amrubicinol in previously treated patients with refractory or relapsed lung cancer. The 15 patients were treated with amrubicin intravenously at doses of 30, 35, or 40 mg/m(2) on three consecutive days every 3 weeks for a total of 43 courses. Neutropenia was the major toxicity (grade 4, 67%). The MTD was 40 mg/m(2), with the specific dose-limiting toxicities being grade 4 neutropenia persisting for >4 days, febrile neutropenia, or grade 3 arrhythmia in the three patients treated at this dose. A patient with non-small-cell lung cancer showed a partial response, and ten individuals experienced a stable disease. The area under the plasma concentration versus time curve (AUC) for amrubicin and that for amrubicinol increased with amrubicin dose. The amrubicin AUC was significantly correlated with the amrubicinol AUC. The recommended phase II dose of amrubicin for patients with lung cancer refractory to standard chemotherapy is thus 35 mg/m(2) once a day for three consecutive days every 3 weeks.

Phase I–II study of amrubicin and cisplatin in previously untreated patients with extensive-stage small-cell lung cancer

BACKGROUND

Amrubicin, a totally synthetic 9-amino-anthracycline, demonstrated excellent single-agent activity for extensive-stage small-cell lung cancer (ED-SCLC). The aims of this trial were to determine the maximum-tolerated doses (MTD) of combination therapy with amrubicin and cisplatin, and to assess the efficacy and safety at their recommended doses (RD).

PATIENTS AND METHODS

Eligibility criteria were patients having histologically or cytologically proven measurable ED-SCLC, no previous systemic therapy, an Eastern Cooperative Oncology Group performance status of 0-2 and adequate organ function. Amrubicin was administered on days 1-3 and cisplatin on day 1, every 3 weeks.

RESULTS

Four patients were enrolled at dose level 1 (amrubicin 40 mg/m(2)/day and cisplatin 60 mg/m(2)) and three patients at level 2 (amrubicin 45 mg/m(2)/day and cisplatin 60 mg/m(2)). Consequently, the MTD and RD were determined to be at level 2 and level 1, respectively. The response rate at the RD was 87.8% (36/41). The median survival time (MST) was 13.6 months and the 1-year survival rate was 56.1%. Grade 3/4 neutropenia and leukopenia occurred in 95.1% and 65.9% of patients, respectively.

CONCLUSIONS

The combination of amrubicin and cisplatin has demonstrated an impressive response rate and MST in patients with previously untreated ED-SCLC.

[Profile of the anti-tumor effects of amrubicin, a completely synthetic anthracycline]

Amrubicin is a completely synthetic anthracycline derivative. In contrast, however, the anthracyclines used clinically thus far have been produced by fermentation or semisynthesis. Amrubicin is structurally distinguishable from other anthracyclines by the amino group at the 9-position and its unique sugar moiety. Amrubicinol, the C-13 hydroxy- metabolite of amrubicin, is associated with a 5 to 200 times greater cytotoxicity than amrubicin. Amrubicin exhibited superior in vivo antitumor activity to doxorubicin in the human tumor xenograft model. Using this model, the level of amrubicinol (active metabolite) was shown to be higher than that of doxorubicin in tumor tissues, but lower in normal tissues. These results suggest potent therapeutic activity for amrubicin because of the selective distribution of its highly active metabolite, amrubicinol, in tumors. These anti-tumor effects of amrubicin are considered to be induced by DNA topoisomeraseII inhibition. In clinical studies, amrubicin has demonstrated potent single agent activity as compared to a standard regimen in untreated patients with extensive small cell lung cancer. Its major toxicity was myelosuppression (especially neutropenia).

Uptake and intracellular distribution of amrubicin, a novel 9-amino-anthracycline, and its active metabolite amrubicinol in P388 murine leukemia cells

Amrubicin, a 9-aminoanthracycline anti-cancer drug, and its C-13 hydroxyl metabolite amrubicinol, were examined for growth-inhibitory activity as well as cellular uptake and distribution in P388 murine leukemia cells and doxorubicin-resistant P388 cells. Also discussed are the differences in the mechanisms of action among amrubicin, amrubicinol and doxorubicin in terms of their cellular pharmacokinetic character. In P388 cells, amrubicinol was about 80 times as potent as amrubicin, and about 2 times more potent than doxorubicin in a 1-h drug exposure growth-inhibition test. A clear cross-resistance was observed to both amrubicin and amrubicinol in doxorubicin-resistant P388 cells, though the resistance index was lower for amrubicin. The intracellular concentration of amrubicinol was about 6 times and 2 times higher than those of amrubicin and doxorubicin, respectively. Compared to doxorubicin, amrubicin and amrubicinol were released rapidly after removal of the drugs from the medium. A clear correlation was found between the growth-inhibiting activity and the cellular level of amrubicin and amrubicinol in P388 cells. About 10 to 20% of amrubicin or amrubicinol taken up by the cells was detected in the cell nuclear fraction, whereas 70 to 80% of doxorubicin was localized in this fraction. These results suggest that amrubicin and amrubicinol exert cytotoxic activity via a different mechanism from that of doxorubicin.

In vivo efficacy and tumor-selective metabolism of amrubicin to its active metabolite

The tissue distribution of a novel antitumor anthracycline antibiotic, amrubicin, was studied using seven human tumor xenografts implanted into nude mice, in order to identify the principal factors determining its therapeutic efficacy. We found a good correlation between the level of the metabolite amrubicinol in the tumor and the in vivo efficacy. High metabolic activity of amrubicin to amrubicinol was detected in tumor tissue homogenates, especially in cell lines highly sensitive to amrubicin in vivo. In contrast to amrubicin, the administration of amrubicinol showed less tumor-selective toxicity in these human tumor xenograft models. These data indicate that the tumor-selective metabolism of amrubicin to amrubicinol resulted in a tumor-selective disposition of amrubicinol, leading to good efficacy in in vivo experimental therapeutic models.