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

Impact of Amrubicin Monotherapy as Second-Line Chemotherapy on Outcomes in Elderly Patients with Relapsed Extensive-Disease Small-Cell Lung Cancer

Purpose

Amrubicin (AMR) is an anticancer drug for patients with relapsed small-cell lung cancer (SCLC). However, the efficacy of AMR in elderly patients with relapsed SCLC after chemotherapy by carboplatin plus etoposide (CE) has not been sufficiently evaluated.

Patients and Methods

The medical records of patients with relapsed SCLC who received AMR as second-line chemotherapy were retrospectively reviewed, and their treatment outcomes were evaluated.

Results

Forty-one patients with a median age of 76 years were analyzed. The overall response rate was 26.8%. Median progression-free survival (PFS) and overall survival (OS) were 3.5 and 8.1 months, respectively. While the median PFS of 4.7 and 2.8 months in the sensitive relapse and the refractory relapse group differed significantly (P=0.043), respectively, the median OS of 10.7 and 6.8 months in the respective relapse groups did not indicate a statistically significant difference (P=0.24). The median PFS in a group with a modified Glasgow prognostic score (mGPS) of 0 and a group with a mGPS 1 or 2 were 4.5 and 1.6 months (P=0.052), respectively, and the median OS in the respective mGPS groups were 10.7 and 4.4 months (P=0.034). Multivariate analysis identified good performance status, limited disease, and mGPS 0 as favorable independent predictors of PFS and OS of AMR monotherapy. Grade 3 or higher neutropenia was observed in 23 patients (56%), and febrile neutropenia was observed in nine patients (22%). Non-hematological toxic effects were relatively mild, and pneumonitis and treatment-related deaths were not observed.

Conclusion

AMR is an effective and feasible regimen for elderly patients with relapsed SCLC after CE therapy.

Individual optimal dose of amrubicin to prevent severe neutropenia in Japanese patients with lung cancer

This study determined individual optimal amrubicin doses for Japanese patients with lung cancer after platinum‐based treatment. We carried out population pharmacokinetic and pharmacodynamic modeling incorporating gene polymorphisms of metabolizing enzymes and transporters. Fifty patients with lung cancer, who were given 35‐40 mg/m² amrubicin on days 1‐3 every 3‐4 weeks, were enrolled. Mechanism‐based modeling described relationships between the pharmacokinetics of amrubicin and absolute neutrophil counts. A population pharmacokinetic and pharmacodynamic model was developed for amrubicin and amrubicinol (active metabolite), connected by a delay compartment. The final model incorporated body surface area as a covariate of amrubicin and amrubicinol clearance and distribution volume. SLC28A3 single nucleotide polymorphism (rs7853758) was also incorporated as a constant covariate of the delay compartment of amrubicinol. Performance status was considered a covariate of pharmacokinetic (amrubicinol clearance) and pharmacodynamic (mean maturation time) parameters. Twenty‐nine patients with grade 4 neutropenia showed higher amrubicinol area under the plasma concentration‐time curve from 0 to 72 hours (AUC_0‐72, P = .01) and shorter overall survival periods than other patients did (P = .01). Using the final population pharmacokinetic and pharmacodynamic model, median optimal dose to prevent grade 4 neutropenia aggravation was estimated at 22 (range, 8−40) mg/m² for these 29 patients. We clarified correlations between area under the plasma concentration‐time curve from 0 to 72 hours of amrubicinol and severity of neutropenia and survival of patients given amrubicin after platinum chemotherapy. This analysis revealed important amrubicin pharmacokinetic‐pharmacodynamic covariates and provided useful information to predict patients who would require prophylactic granulocyte colony stimulating factor.

Amrubicin monotherapy for elderly patients with relapsed extensive-disease small-cell lung cancer: A retrospective study

Background

Previous studies have shown amrubicin (AMR) to be an effective second‐line treatment option for small‐cell lung cancer (SCLC). However, the efficacy of AMR in elderly patients with relapsed SCLC has not been sufficiently evaluated.

Methods

The medical records of elderly patients with relapsed SCLC who received AMR as second‐line chemotherapy were retrospectively reviewed, and their treatment outcomes were evaluated.

Results

Thirty‐one patients with a median age of 72 years (22 patients with sensitive relapse and 9 with refractory relapse) were analyzed. The median number of treatment cycles was four (range: 1–10), and the response rate was 29%. The median progression‐free survival (PFS) and overall survival (OS) were 5.4 and 11.6 months, respectively. The OS of 22 patients who received third‐line chemotherapy was 15.5 months. The PFS (6.2 vs. 3.2 months; P = 0.002) and OS (14.8 vs. 5.7 months; P = 0.004) were significantly longer in patients with sensitive relapse than those with refractory relapse. The frequency of grade 3 or higher neutropenia was high (n = 18, 58%), while febrile neutropenia was only observed in five patients (16%). Non‐hematological toxic effects were relatively mild, and pneumonitis and treatment‐related deaths were not observed.

Conclusion

AMR may be a feasible and effective regimen for elderly patients with relapsed SCLC.

Comparison of carboplatin plus etoposide with amrubicin monotherapy for extensive-disease small cell lung cancer in the elderly and patients with poor performance status

BACKGROUND

Carboplatin plus etoposide (CE) is a standard treatment for elderly patients with extensive-disease small cell lung cancer (ED-SCLC). However, amrubicin monotherapy (AMR) may be a feasible alternative. We compared the efficacies and safety profiles of CE and AMR for ED-SCLC in elderly patients and chemotherapy-naive patients with poor performance status (PS).

METHODS

The records of SCLC patients who received CE or AMR as first-line chemotherapy were retrospectively reviewed and their treatment outcomes evaluated.

RESULTS

Eighty-four patients (median age 72 years; 42 each received CR and AMR) were analyzed; 34 patients had a PS score of 2. There were no significant differences in patient characteristics between the treatment groups. The median progression-free survival rates of patients in the CE and AMR groups were 5.8 and 4.8 months, respectively (P = 0.04); overall survival was 14.0 and 8.5 months, respectively (P = 0.089). Twenty-three CE group patients received AMR as second-line chemotherapy; their median overall survival from first-line chemotherapy was 18.5 months. Grade 3 or higher neutropenia occurred more frequently in patients treated with AMR (64% vs. 40%; P = 0.02), as did febrile neutropenia (14% vs. 7%).

CONCLUSIONS

CE remains a suitable first-line treatment for ED-SCLC in elderly patients or those with poor PS in comparison with AMR.

A retrospective study of amrubicin monotherapy for the treatment of relapsed small cell lung cancer in elderly patients

Purpose

Amrubicin is one of the most active chemotherapeutic drugs for small cell lung cancer (SCLC). Previous studies reported its effectiveness and severe hematological toxicity. However, the efficacy of amrubicin monotherapy in elderly patients with SCLC has not been described. The objective of this study was to investigate the feasibility of amrubicin monotherapy in elderly patients and its efficacy for relapsed SCLC.

Methods

A retrospective cohort study design was used. We retrospectively evaluated the clinical effects and adverse events of amrubicin treatment in elderly (≥70 years) SCLC patients with relapsed SCLC.

Results

Between November 2003 and September 2015, 86 patients (aged ≥70 years) received amrubicin monotherapy for relapsed SCLC at four institutions. There were 42 cases of sensitive relapse (S) and 44 of refractory relapse (R). S cases with median age of 75 years (range 70–85 years) and R cases with median age of 74 years (range 70–84 years) were included in our analysis. The median number of treatment cycles was three (range 1–9), and the response rate was 33.7% (40.5% in the S and 27.2% in the R cases). Median progression-free survival time was 4.0 months in the S and 2.7 months in the R patients (p = 0.013). Median survival time from the start of amrubicin therapy was 7.6 months in the S and 5.5 months in the R cases (p = 0.26). The frequencies of grade ≥3 hematological toxicities were as follows: leukopenia, 60.4%; neutropenia, 74.4%; anemia, 11.6%; thrombocytopenia, 16.2%; and febrile neutropenia, 17.4%. Treatment-related death was observed in one patient.

Conclusion

Although hematological toxicities, particularly neutropenia, were severe, amrubicin showed favorable efficacy, not only in the S but also in the R cases, as shown in previous studies. Amrubicin could be a preferable standard treatment in elderly patients with relapsed SCLC. These results warrant further evaluation of amrubicin in elderly patients with relapsed SCLC by a prospective trial.

Electronic supplementary material

The online version of this article (doi:10.1007/s00280-017-3403-9) contains supplementary material, which is available to authorized users.

Phase II study of Amrubicin monotherapy in elderly or poor-risk patients with extensive disease of small cell lung cancer

Background Previous study indicated that an optional anti-cancer drug for the treatment of small-cell lung cancer (SCLC) is amrubicin. However, no prospective studies have evaluated amrubicin in chemo-naive elderly or poor-risk patients with SCLC. Therefore, this study aimed to evaluate the efficacy of amrubicin as first-line chemotherapy for elderly or poor-risk patients with extensive-disease SCLC (ES-SCLC). Methods Patients with chemotherapy-naive ES-SCLC received multiple cycles of 40 mg/m² amrubicin for 3 consecutive days every 21 days. The primary endpoint was the overall response rate (ORR), and the secondary endpoints were progression-free survival (PFS), overall survival (OS), and safety. Results Between March 2011 and August 2015, 36 patients were enrolled in this study. Each patient received a median of four treatment cycles (range, 1-6 cycles). ORR was 52.8% [95% confidence interval (CI), 37-69%]. The median PFS and OS periods were 5.0 months (95% CI, 3.4-6.6 months) and 9.4 months (95% CI, 5.2-13.6 months), respectively. Neutropenia was the most common grade 3 or 4 adverse event (69.4%), with febrile neutropenia developing in 13.9% of patients. No treatment-related death occurred. At the time of starting second-line chemotherapy, 19 of 22 patients (86%) had significantly improved or maintained their performance status (PS) relative to their PS at the time of starting amrubicin monotherapy as first-line chemotherapy (P = 0.027). Conclusions The results of the present study suggest that amrubicin could be considered as a viable treatment option for chemotherapy-naive elderly or poor-risk patients with ES-SCLC (Clinical trial registration number: UMIN000011055 www.clinicaltrials.gov ).

Simultaneous optimization of limited sampling points for pharmacokinetic analysis of amrubicin and amrubicinol in cancer patients

AIM

Limited sampling points for both amrubicin (AMR) and its active metabolite amrubicinol (AMR-OH) were simultaneously optimized using Akaike's information criterion (AIC) calculated by pharmacokinetic modeling.

METHODS

In this pharmacokinetic study, 40 mg/m(2) of AMR was administered as a 5-min infusion on three consecutive days to 21 Japanese lung cancer patients. Blood samples were taken at 0, 0.08, 0.25, 0.5, 1, 2, 4, 8 and 24 h after drug infusion, and AMR and AMR-OH concentrations in plasma were quantitated using a high-performance liquid chromatography. The pharmacokinetic profile of AMR was characterized using a three-compartment model and that of AMR-OH using a one-compartment model following a first-order absorption process. These pharmacokinetic profiles were then integrated into one pharmacokinetic model for simultaneous fitting of AMR and AMR-OH. After fitting to the pharmacokinetic model, 65 combinations of four sampling points from the concentration profiles were evaluated for their AICs. Stepwise regression analysis was applied to select the sampling points for AMR and AMR-OH to predict the area under the concentration-time curves (AUCs) at best.

RESULTS

Of the three combinations that yielded favorable AIC values, 0.25, 2, 4 and 8 h yielded the best AUC prediction for both AMR (R(2) = 0.977) and AMR-OH (R(2) = 0.886). The prediction error for AUC was less than 15%.

CONCLUSION

The optimal limited sampling points of AMR and AMR-OH after AMR infusion were found to be 0.25, 2, 4 and 8 h, enabling less frequent blood sampling in further expanded pharmacokinetic studies for both AMR and AMR-OH.

Dose escalation and pharmacokinetic study of carboplatin plus pemetrexed for elderly patients with advanced nonsquamous non-small-cell lung cancer: Kumamoto thoracic oncology study group trial 1002

OBJECTIVES

This study was designed to determine the recommended dose of carboplatin and pemetrexed for elderly (≥70-year-old) chemotherapy-naïve patients with advanced nonsquamous non-small-cell lung cancer (NSCLC) and to investigate the pharmacokinetics of pemetrexed.

METHODS

The patients were treated with 4-6 cycles of carboplatin plus a fixed dose of pemetrexed (500 mg/m(2)) every 3 weeks; the dose of carboplatin was escalated [from area under the curve (AUC) 4 to AUC 6]. To examine the pharmacokinetics of pemetrexed, blood samples were collected before and after pemetrexed infusion, and the blood levels of pemetrexed were measured by liquid chromatography-mass spectrometry.

RESULTS

Grade 3 infection as a dose-limiting toxicity was observed at a carboplatin dose of AUC 6. We therefore determined a carboplatin dose of AUC 5 and a pemetrexed dose of 500 mg/m(2) as the recommended doses from this study. The pharmacokinetic study showed a significant inverse correlation between the AUC of pemetrexed and the creatinine clearance.

CONCLUSIONS

For elderly chemotherapy-naïve patients with advanced nonsquamous NSCLC, the combination of carboplatin AUC 5 plus pemetrexed 500 mg/m(2) is recommended as a promising regimen; however, a reduction of the pemetrexed dose may be required for patients with renal dysfunction because of the high risk of hematotoxicities.

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.

A phase I/II trial of irinotecan plus amrubicin supported with G-CSF for extended small-cell lung cancer

OBJECTIVE

This study reports the findings of a Phase I/II, cohort, dose-escalation trial of amrubicin and irinotecan with the support of granulocyte colony-stimulation factor. This study aimed to determine the dose-limiting toxicity of the combination and to define the maximum-tolerated dose, as a recommended dose for Phase II trials. We also sought to obtain preliminary data on the efficacy of this combination as a frontline therapy for extensive-disease small-cell lung cancer.

METHODS

We included 23 chemo-naïve patients with extensive-disease small-cell lung cancer in the trial. The amrubicin dose was escalated from 35 to 40 mg/m(2) (Levels 1 and 2, respectively) to determine the dose-limiting toxicity, with an unchanged dose of irinotecan at 50 mg/m(2).

RESULTS

Of nine patients, three experienced dose-limiting toxicities at Level 1 of prolonged Grade 4 neutropenia, Grade 3 febrile neutropenia and Grade 3 febrile neutropenia with Grade 3 diarrhea. At Level 2, two patients experienced dose-limiting toxicities of Grade 4 neutropenia and Grade 3 neutropenia with Grade 4 diarrhea. The maximum-tolerated doses and recommended doses for amrubicin and irinotecan were therefore determined to be 35 and 50 mg/m(2), respectively. The Level 1 trial was then expanded to 21 patients, 14 (70%) of whom showed partial responses to the recommended dose. The median progression-free and overall survival times were 6.37 and 15.21 months, respectively.

CONCLUSIONS

The combination of amrubicin and irinotecan with the support of granulocyte colony-stimulation factor produced a potent effect in chemo-naïve extensive-disease small-cell lung cancer patients. The use of biomarkers for this regimen may identify patients who are likely to suffer from treatment-ending severe adverse effects.

Amrubicin: potential in combination with cisplatin or carboplatin to treat small-cell lung cancer

Small-cell lung cancer (SCLC) is the most aggressive form of lung cancer characterized by early metastasis and high mortality. In recent years, monotherapy and combination therapy of amrubicin with cisplatin or carboplatin has been actively studied and shown promise for the treatment of extensive disease SCLC (ED-SCLC). In this article, we summarize clinical trials of both monotherapy and combination therapy with amrubicin conducted in Japan, the USA, and the European Union. The results suggest that the clinical outcome of amrubicin therapy may be associated with genetic variations in patients. Further study of combination regimens in patients of different ethnicities is warranted.

A phase II study of amrubicin as a third-line or fourth-line chemotherapy for patients with non-small cell lung cancer: Hokkaido Lung Cancer Clinical Study Group Trial (HOT) 0901

Amrubicin, a third-generation synthetic anthracycline agent, has favorable clinical activity and acceptable toxicity for the treatment of patients with non-small cell lung cancer (NSCLC) and small cell lung cancer. We conducted this study to evaluate the efficacy and safety of amrubicin for advanced NSCLC patients as a third- or fourth-line therapy. Eligible patients had recurrent or refractory advanced NSCLC after second- or third-line therapy. Patients received amrubicin, 35 mg/m(2) i.v. on days 1-3 every 3 weeks. The primary endpoint was the disease control rate (DCR). Secondary endpoints were the overall survival (OS) time, progression-free survival (PFS) time, response rate, and toxicity profile. Of the 41 patients enrolled, 26 received amrubicin as a third-line and 15 received it as a fourth-line therapy. The median number of treatment cycles was two (range, 1-9). Objective responses were complete response (n = 0), partial response (n = 4), stable disease (n = 21), progressive disease (n = 15), and not evaluable (n = 1), resulting in a DCR of 61.0% (95% confidence interval, 46.0%-75.9%). The overall response rate was 9.8% (95% confidence interval, 0.6%-18.8%). The median PFS interval was 3.0 months, median OS time was 12.6 months, and 1-year survival rate was 53.7%. Grade 3 or 4 hematological toxicities were neutropenia (68%), anemia (12%), thrombocytopenia (12%), and febrile neutropenia (17%). Nonhematological toxicities were mild and reversible. No treatment-related deaths were observed. Amrubicin showed significant clinical activity with manageable toxicities as a third- or fourth-line therapy for patients with advanced NSCLC. This study provides relevant data for routine practice and future prospective trials evaluating third- or fourth-line treatment strategies for patients with advanced NSCLC.

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.

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.

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.

Phase II trial of amrubicin and carboplatin in patients with sensitive or refractory relapsed small-cell lung cancer

Amrubicin is a novel, totally synthesized anthracycline derivative, and has antitumor activity against several human tumor xenografts. The combination of amrubicin with platinum derivative showed additive effect against a human small-cell lung cancer (SCLC) cell line. Until now, the combination of amrubicin plus carboplatin has not been studied in patients with previously treated SCLC. Therefore, we examined the safety and efficacy of the combination of amrubicin plus carboplatin in patients with sensitive or refractory relapsed SCLC. Patients with previously treated SCLC were eligible if they had a performance status of 2 or less, were 75 years or younger, and had adequate organ function. Twenty-five patients were enrolled (21 men and 4 women; median age, 65 years; age range 55-73 years). Patients received the combination of amrubicin (30 mg/m(2) on days 1-3) plus carboplatin (with a target area under the concentration-versus-time curve of 4 mg min/ml using the Calvert formula on day 1) every 3 weeks. The overall response rate was 36.0% (95% confidence interval [CI], 18.0-57.5%). Response rates differed significantly between patients with sensitive relapse (58.3%; 95% CI, 27.7-84.8%) and those with refractory relapse (15.4%; 95% CI, 1.9-15.4%; p=0.03). The median survival time (MST) from the start of this treatment was 7 months (range: 1-42 months); the MST of patients with sensitive relapse (10 months) was significantly longer than that of patients with refractory relapse (5 months: p=0.004). The median progression-free survival (PFS) time was 3 months (range: 1-14 months): the median PFS time of patients with sensitive relapse (5 months) was significantly longer than that of patients with refractory relapse (2 months; p=0.01). The most frequent grade 3-4 toxicity was myelosuppression, especially neutropenia, which developed in 88% of patients. Grade 3-4 thrombocytopenia developed in 44% of patients, and anemia developed in 56%. Nonhematologic toxicities were generally mild to moderately severe and temporary. None of the patients had cardiotoxicity. In conclusion, this therapy is effective and well tolerated for previously treated 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.

Amrubicin for the treatment of advanced lung cancer

Although the advancement of the chemotherapy of non-small cell lung cancer and small cell lung cancer is remarkable in recent years, it is still unsatisfactory. Therefore, some new agents or a new treatment strategy for lung cancer is required. Amrubicin is a totally synthetic anthracycline anticancer drug that acts as a potent topoisomerase II inhibitor. Recently, amrubicin has been approved in Japan for the treatment of small- and non-small cell lung cancers and some clinical trials about amrubicin were conducted in Japan, and promising results have been reported for the treatment of small cell lung cancer in particular. The preclinical, pharmacology and clinical data of amrubicin for the treatment of advanced lung cancer are reviewed.

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.

Amrubicin monotherapy for elderly patients with previously treated lung cancer

OBJECTIVE

The novel anthracycline agent amrubicin, has been approved in Japan to treat small and non-small cell lung cancers (SCLC and NSCLC). The present study evaluates the toxicity and effect of amrubicin especially in elderly patients with previously treated lung cancer.

PATIENTS AND METHODS

This retrospective study analyzed data from 51 patients (<70 years of age, n=29; > oor =70 years of age, n=22) with lung cancer (NSCLC, n=21; SCLC, n=30) who were treated with amrubicin at our hospital, between July 2003 and October 2009. All patients had recurrent or refractory lung cancer after one or more chemotherapy regimens. We compared the outcomes of patients younger and older than 70 years of age. Amrubicin (30-40 mg/m(2)/day) was infused depending on patient performance status and laboratory data over a period of 5 minutes on days 1-3, with courses repeated at intervals of at least 3 weeks. The dose was modified according to myelosuppression.

RESULTS

The mean number of treatment cycles, mean dose and mean interval of amrubicin administration did not significantly differ between patients aged <70 and > or =70 years. The rate of hematological toxicities (> or = Grade 3) also did not significantly differ between the two age groups (leukopenia, 48.3% and 59.1% for age <70 and > or =70 years, p=0.573; neutropenia, 65.5% vs. 77.3%, p=0.536; anemia, 20.7% vs. 22.7%, p=1.000; thrombocytopenia, 13.8% vs. 31.8%, p=0.173). The incidence of grade 2-4 non-hematological toxicities also did not significantly differ between the groups. The response rate of SCLC and disease control rate of NSCLC were similar in the younger and older groups.

CONCLUSION

Amrubicin monotherapy might be equally tolerated by elderly and younger patients. Further studies are needed to investigate the benefit of amrubicin monotherapy among elderly patients with previously treated lung cancer.

A phase II study of amrubicin, a synthetic 9-aminoanthracycline, in patients with previously treated lung cancer

PURPOSE

This study was designed to confirm the efficacy and safety of amrubicin, a new anthracycline agent, in patients with previously treated non-small cell lung cancer (NSCLC) and small cell lung cancer (SCLC).

METHODS

Eligible patients were required to have recurrent or refractory NSCLC and SCLC after one or two previous chemotherapy regimens. All patients received intravenous amrubicin 35 mg/m(2) on days 1-3 every 3 weeks. Overall response rate (ORR), progression-free survival (PFS), and overall survival (OS) were evaluated.

RESULTS

Sixty-six patients (37 NSCLC and 29 SCLC) were assessable for efficacy and safety evaluation. Grade 3 or 4 neutropenia was observed in 39.4% of all patients (NSCLC, 37.8%; SCLC, 41.4%). Nonhematological toxicities were mild. No treatment-related death was observed. The ORRs were 13.5% (95% CI, 4.5-28.8%) in NSCLC and 44.8% (95% CI, 26.4-64.3%) in SCLC. In SCLC, ORRs were 60.0% in the sensitive relapse and 36.8% in the refractory relapse (p=0.2332). In NSCLC, the PFS, OS, and 1-year survival were 3.3 months, 12.0 months, and 35.3%, respectively. In SCLC, the PFS, OS, and 1-year survival were 4.0 months, 12.0 months, and 46.7%, respectively.

CONCLUSIONS

Amrubicin is an active and well-tolerated regimen in patients with previously treated lung cancer. Amrubicin 35 mg/m(2) seems to achieve similar efficacy with less toxicity than amrubicin 40 mg/m(2) in this patient population. These results warrant further evaluation in previously treated lung cancer.

Amrubicin for non-small-cell lung cancer and small-cell lung cancer

Amrubicin is a totally synthetic anthracycline anticancer drug and a potent topoisomerase II inhibitor. Recently, amrubicin was approved in Japan for the treatment of small- and non-small-cell lung cancers (SCLC and NSCLC). Here, we review the efficacy and toxicities of amrubicin monotherapy and amrubicin in combination with cisplatin for extensive-disease SCLC (ED-SCLC), and of amrubicin monotherapy for advanced NSCLC, as observed in the clinical trials. Recommended dosage for previously untreated advanced NCSLC was 45 mg/m2/day by intravenous administration for 3 days. Dose-limiting toxicities were leucopenia, thrombocytopenia, and gastrointestinal disturbance. Response rate was 27.9% for advanced NSCLC, and 75.8% for ED-SCLC with a median survival time (MST) of 11.7 months. Recommended dosage of amrubicin was 40 mg/m2/day in combination with cisplatin at 60 mg/m2/day, with MST of 13.6 months and 1-year survival rate of 56.1%. In sensitive or refractory relapsed SCLC, response rate was 52 and 50%, progression-free survival was 4.2 and 2.6 months, overall survival was 11.6 and 10.3 months, and 1-year survival rate was 46 and 40%, respectively. These results are promising for the treatment of both NSCLC and SCLC. Further clinical trials will clarify the status of amrubicin in the treatment of lung cancer.

Experimental designs for phase I and phase I/II dose-finding studies

We review the rationale behind the statistical design of dose-finding studies as used in phase I and phase I/II clinical trials. We underline what the objectives of such dose-finding studies should be and why the widely used standard design fails to meet any of these objectives. The standard design is a "memoryless" design and we discuss how this impacts on practical behaviour. Designs introduced over the last two decades can be viewed as designs with memory and we discuss how these designs are superior to memoryless designs. By superior we mean that they require less patients overall, less patients to attain the maximum tolerated dose (MTD), and concentrate a higher percentage of patients at and near to the MTD. We reanalyse some recently published studies in order to provide support to our contention that markedly better results could have been achieved had a design with memory been used instead of a memoryless design.