Phase II study of irinotecan plus capecitabine in anthracycline- and taxane- pretreated patients with metastatic breast cancer

A Retrospective Analysis of the Effect of Irinotecan-Based Regimens in Patients With Metastatic Breast Cancer Previously Treated With Anthracyclines and Taxanes

Background

At present, patients with metastatic breast cancer (MBC) have few treatment options after receiving anthracyclines and taxanes. Studies have shown that irinotecan has modest systemic activity in some patients previously treated with anthracyclines and taxanes. This study aimed to evaluate the efficacy of irinotecan-based chemotherapy for breast cancer patients in a metastatic setting.

Methods

We retrospectively collected the clinical information and survival data of 51 patients with MBC who received irinotecan at West China Hospital of Sichuan University. The primary endpoints were the progression free survival (PFS) and overall survival (OS), and the secondary endpoint was the objective response rate (ORR). To minimize potential confounding factors, we matched 51 patients who received third-line chemotherapy without irinotecan through propensity score matching (PSM) based on age, hormone receptor (HR), and human epidermal growth factor receptor 2 (HER2), compared their OS and PFS rates to those treated with irinotecan.

Results

From July 2012 to October 2020, 51 patients were treated with an irinotecan-containing regimen. The median number of previous treatment lines was 4, and a median of two previous chemotherapy cycles (ranging from 1–14 cycles) were given in a salvage line setting. The ORR was 15.7%, and the disease control rate (DCR) was 37.3%. For the irinotecan group, the median PFS was 3.2 months (95% CI 2.7–3.7), while the median OS was 33.1 months (95% CI 27.9–38.3). Univariate analysis results suggested that irinotecan could improve PFS in patients with visceral metastasis (P=0.031), which was 0.7 months longer than patients without visceral metastasis (3.5 months vs. 2.8 months). Compared to the patients who received third-line non-irinotecan chemotherapy, the irinotecan group showed a longer trend of PFS without statistical significance (3.2 months vs 2.1 months, P = 0.052). Similarly, the OS of the irinotecan group was longer than the third-line survival without irinotecan, but it was not statistically significant (33.1 months vs 18.0 months, P = 0.072).

Conclusions

For MBC patients who were previously treated with anthracyclines and/or taxanes, an irinotecan-containing regimen achieved moderate objective response and showed a trend of survival benefit, which deserves further study.

Chemotherapy Options beyond the First Line in HER-Negative Metastatic Breast Cancer

Despite the recent advances in the biological understanding of breast cancer (BC), chemotherapy still represents a key component in the armamentarium for this disease. Different agents are available as mono-chemotherapy options in patients with locally advanced or metastatic BC (MBC) who progress after a first- and second-line treatment with anthracyclines and taxanes. However, no clear indication exists on what the best option is in some populations, such as heavily pretreated, elderly patients, triple-negative BC (TNBC), and those who do not respond to the first-line therapy. In this article, we summarize available literature evidence on different chemotherapy agents used beyond the first-line, in locally advanced or MBC patients, including rechallenge with anthracyclines and taxanes, antimetabolite and antimicrotubule agents, such as vinorelbine, capecitabine, eribulin, ixabepilone, and the newest developed agents, such as vinflunine, irinotecan, and etirinotecan.

Phase I study of liposomal irinotecan in patients with metastatic breast cancer: findings from the expansion phase

Purpose

Metastatic breast cancer (mBC) remains incurable and is associated with low survival rates. This study assessed the efficacy and safety of liposomal irinotecan in heavily pretreated patients with mBC, with or without active brain metastases (BM).

Methods

Following the dose escalation phase and determination of recommended phase 2 dose, the expansion phase of this phase I, open-label, non-randomized study, assigned adult women to cohorts based on mBC subtype: cohort 1, hormone receptor +/human epidermal growth factor receptor 2−; cohort 2, triple-negative breast cancer; or cohort 3, any mBC subtype with active BM. Patients received liposomal irinotecan 50 or 70 mg/m² free base every 2 weeks. Here, we report secondary outcomes including best overall response (BOR), objective response rate (ORR), and treatment-emergent adverse events (TEAEs).

Results

For non-central nervous system (non-CNS) disease across all cohorts (intent-to-treat population, N = 29), the ORR was 34.5% (95% confidence interval: 17.94–54.33), with a BOR of partial response in 10 patients (34.5%), stable disease in five (17.2%), progressive disease in 10 (34.5%); four patients were unevaluable (13.8%). The ORR for the CNS cohort was 30.0% (95% confidence interval: 6.67–65.25) using modified Response Evaluation Criteria in Solid Tumors. Common grade 3 or higher TEAEs were diarrhea (27.6%), nausea (17.2%), fatigue (13.8%), asthenia (10.3%), and hypokalemia (10.3%). Serious treatment-related TEAEs were reported in six patients (20.7%). No treatment-related TEAEs resulted in death.

Conclusions

Liposomal irinotecan monotherapy demonstrated antitumor activity in heavily pretreated patients with mBC, with or without BM. The observed safety profile was consistent with that in previous studies.

Clinical trial registration: Trial registration ID NCT01770353.

Electronic supplementary material

The online version of this article (10.1007/s10549-020-05995-7) contains supplementary material, which is available to authorized users.

An open label phase 1 study evaluation safety, tolerability, and maximum tolerated dose of oral administration of irinotecan in combination with capecitabine

PURPOSE

Oral administration of chemotherapy offers several advantages in comparison with intravenous administration. Previously, data on a new oral formulation of irinotecan have been published. The aim of the present study was to evaluate the safety, tolerability, and Maximum Tolerated Dose (MTD) of the new oral irinotecan formulation in combination with oral capecitabine.

METHODS

The study was an open label, phase 1, single center, extension part in which oral irinotecan was investigated in combination with capecitabine. The MTD of irinotecan in combination with capecitabine was 17.5 mg/m² once daily for 14 consecutive days in combination with capecitabine 800 mg/m² twice daily. Eligible patients were adults with metastatic or unresectable solid tumors for which no standard curative or palliative therapies existed.

RESULTS

14 patients were included in the extension part. No grade 3 or 4 hematologic toxicities were observed. Non-hematological toxicities included grade 1 and 2 diarrhea, fatigue, cholinergic syndrome, vomiting, and weight loss. Totally, 3 grade 3 toxicities and no grade 4 event were reported. No objective responses were observed. Five patients had stable disease lasting median 14 weeks.

CONCLUSIONS

Capecitabine in combination with oral irinotecan could be a new treatment option offering a more convenient and patient friendly treatment strategy compared to intravenous irinotecan. The combination is fairly tolerated; however, further investigations are needed to assess the efficacy of this regimen.

Change in Topoisomerase 1-Positive Circulating Tumor Cells Affects Overall Survival in Patients with Advanced Breast Cancer after Treatment with Etirinotecan Pegol

Purpose: Preplanned exploratory analyses were performed to identify biomarkers in circulating tumor cells (CTC) predictive of response to the topoisomerase 1 inhibitor etirinotecan pegol (EP).Experimental Design: The BEACON trial treated patients with metastatic breast cancer (MBC) with EP or treatment of physician's choice (TPC). Blood from 656 of 852 patients (77%) was processed with ApoStream to enrich for CTCs. A multiplex immunofluorescence assay measured expression of candidate response biomarkers [topoisomerase 1 (Top1), topoisomerase 2 (Top2), Ki67, RAD51, ABCG2, γH2AX, and terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL)] in CTCs. Patients were classified as Top1 low (Top1Lo) or Top1 high (Top1Hi) based on median CTC Top1 expression. Correlation of CTC biomarker expression at baseline, cycle 2 day 1 (C2D1), and cycle 4 day 1 with overall survival (OS) was investigated using Cox regression and Kaplan-Meier analyses.Results: Overall, 98% of samples were successfully processed, of which 97% had detectable CTCs (median, 47-63 CTCs/mL; range, 0-2,020 CTCs/mL). Top1, Top2, and TUNEL expression was detected in 52% to 90% of samples; no significant associations with OS were observed in pretreatment samples for either group. EP-treated patients with low C2D1Top1⁺ CTCs had improved OS compared with those with higher positivity (14.1 months vs. 11.0 months, respectively; HR, 0.7; P = 0.02); this difference was not seen in TPC-treated patients (HR, 1.12; P = 0.48). Patients whose CTCs decreased from Top1Hi to Top1Lo at C2D1 had the greatest OS benefit from EP (HR, 0.57; P = 0.01).Conclusions: CTC Top1 expression following EP treatment may identify patients with MBC most likely to have an OS benefit. Clin Cancer Res; 24(14); 3348-57. ©2018 AACR.

Randomized Open Label Phase III Trial of Irinotecan Plus Capecitabine versus Capecitabine Monotherapy in Patients with Metastatic Breast Cancer Previously Treated with Anthracycline and Taxane: PROCEED Trial (KCSG BR 11-01)

Purpose

We investigated whether irinotecan plus capecitabine improved progression-free survival (PFS) compared with capecitabine alone in patients with human epidermal growth factor 2 (HER2) negative and anthracycline and taxane pretreated metastatic breast cancer (MBC).

Materials and Methods

A total of 221 patients were randomly assigned to irinotecan (80 mg/m², days 1 and 8) and capecitabine (1,000 mg/m² twice a day, days 1-14) or capecitabine alone (1,250 mg/m² twice a day, days 1-14) every 3 weeks. The primary endpoint was PFS.

Results

There was no significant difference in PFS between the combination and monotherapy arm (median, 6.4 months vs. 4.7 months; hazard ratio [HR], 0.84; 95% confidence interval [CI], 0.63 to 1.11; p=0.84). In patients with triple-negative breast cancer (TNBC, n=90), the combination significantly improved PFS (median, 4.7 months vs. 2.5 months; HR, 0.58; 95% CI, 0.37 to 0.91; p=0.02). Objective response rate was numerically higher in the combination arm, though it failed to reach statistical significance (44.4% vs. 33.3%, p=0.30). Overall survival did not differ between arms (median, 20.4 months vs. 24.0 months; p=0.63). While grade 3 or 4 neutropenia was more common in the combination arm (39.6% vs. 9.0%), hand-foot syndrome was more often observed in capecitabine arm. Quality of life measurements in global health status was similar. However, patients in the combination arm showed significantly worse symptom scales especially in nausea/vomiting and diarrhea.

Conclusion

Irinotecan plus capecitabine did not prove clinically superior to single-agent capecitabine in anthracycline- and taxane-pretreated HER2 negative MBC patients. Toxicity profiles of the two groups differed but were manageable. The role of added irinotecan in patients with TNBC remains to be elucidated.

A meta-analysis of combination therapy versus single-agent therapy in anthracycline- and taxane-pretreated metastatic breast cancer: results from nine randomized Phase III trials

Nowadays, the philosophy of treating metastatic breast cancer (MBC) is slowly evolving. Especially for the anthracycline- and taxane-pretreated MBC patients, no standard therapy exists in this setting. Whether to choose doublet agents or single agent as salvage treatment remains fiercely debated. Thus, we conducted a meta-analysis to resolve this problem. Databases including PubMed, EMBASE, and Cochrane library were searched for Phase III randomized clinical trials (published before August 2015) comparing the efficacy and adverse effects between the combination therapy and single-agent therapy in anthracycline- and taxane-pretreated MBC patients. The primary end point was the overall survival (OS), and the secondary end points were the progression-free survival (PFS), overall response rate (ORR), and grade 3 or 4 toxicities. The pooled hazard ratio (HR) and pooled risk ratio (RR) were used to evaluate the efficacy. Analyses were also performed to estimate the side effects and safety of both groups. In all, nine eligible randomized clinical trials were included in this meta-analysis. Improvements were proven in the doublet agents group on OS (HR 0.90, 95% confidence interval [CI] 0.84–0.96, P=0.002), PFS (HR 0.81, 95% CI 0.76–0.88, P<0.001), and ORR (RR 1.72, 95% CI 1.34–2.21, P<0.001). Notably, subgroup analysis failed to favor the targeted agent-based combination in terms of OS (HR 1.08, 95% CI 0.89–1.31, P=0.365), PFS (HR 1.09, 95% CI 0.88–1.35, P=0.433), and ORR (RR 1.60, 95% CI 0.69–3.71, P=0.278) compared with single agent. In addition, although more hematological and gastrointestinal toxicities were observed in the doublet agents group, they were acceptable and manageable. Taken together, when compared with single-agent therapy, doublet agents should be considered a treatment option because of the superior efficacy and the manageable safety profile for the prior anthracycline- and taxane-treated MBC patients.

Irinotecan and capecitabine combination chemotherapy in a patient with triple-negative breast cancer relapsed after adjuvant chemotherapy with anthracycline and taxane

The most effective regimen for taxane- and anthracycline-refractory triple-negative breast cancer (TNBC) has not yet been established. Capecitabine was approved by the US Food and Drug Administration for the treatment of advanced breast cancer and has shown efficacy in advanced breast cancer refractory to anthracyclines and taxanes. Irinotecan has synergism with 5-fluorouracil and shows efficacy in advanced breast cancer. Here we report on a patient with TNBC who relapsed with widespread bone and lung metastases shortly after adjuvant anthracycline followed by taxane chemotherapy. She achieved a metabolic complete response with irinotecan and capecitabine combination therapy and had 10 months' progression-free survival and 22 months' overall survival. She relapsed with and died of brain metastasis without any definite signs of progression of the lung and bone lesions she had had before the irinotecan and capecitabine combination therapy. To validate this favorable result, larger clinical trials are warranted in patients with metastatic or relapsed TNBC.

Molecular insights into microbial β-glucuronidase inhibition to abrogate CPT-11 toxicity

Bacterial β-glucuronidases expressed by the symbiotic intestinal microbiota appear to play important roles in drug-induced epithelial cell toxicity in the gastrointestinal (GI) tract. For the anticancer drug CPT-11 (irinotecan) and the nonsteroidal anti-inflammatory drug diclofenac, it has been shown that removal of the glucuronide moieties from drug metabolites by bacterial β-glucuronidases in the GI lumen can significantly damage the intestinal epithelium. Furthermore, selective disruption of bacterial β-glucuronidases by small molecule inhibitors alleviates these side effects, which, for CPT-11 {7-ethyl-10-[4-(1-piperidino)-1-piperidino]}, can be dose limiting. Here we characterize novel microbial β-glucuronidase inhibitors that inhibit Escherichia coli β-glucuronidase in vitro with Ki values between 180 nM and 2 μM, and disrupt the enzyme in E. coli cells, with EC50 values as low as 300 nM. All compounds are selective for E. coli β-glucuronidase without inhibiting purified mammalian β-glucuronidase, and they do not impact the survival of either bacterial or mammalian cells. The 2.8 Å resolution crystal structure of one inhibitor bound to E. coli β-glucuronidase demonstrates that it contacts and orders only a portion of the "bacterial loop" present in microbial, but not mammalian, β-glucuronidases. The most potent compound examined in this group was found to protect mice against CPT-11-induced diarrhea. Taken together, these data advance our understanding of the chemical and structural basis of selective microbial β-glucuronidase inhibition, which may improve human drug efficacy and toxicity.