Metronomic administration of pegylated liposomal-doxorubicin in extensively pre-treated metastatic breast cancer patients: A mono-institutional case-series report

Nanoparticle-mediated metronomic chemotherapy in cancer: A paradigm of precision and persistence

Current methods of cancer therapy have demonstrated enormous potential in tumor inhibition. However, a high dosage regimen of chemotherapy results in various complications which affect the normal body cells. Tumor cells also develop resistance against the prescribed drugs in the whole treatment regimen increasing the risk of cancer relapse. Metronomic chemotherapy is a modern treatment method that involves administering drugs at low doses continuously, allowing the drug sufficient time to take its effect. This method ensures that the toxicity of the drugs is to a minimum in comparison to conventional chemotherapy. Nanoparticles have shown efficacy in delivering drugs to the tumor cells in various cancer therapies. Combining nanoparticles with metronomic chemotherapy can yield better treatment results. This combination stimulates the immune system, improving cancer cells recognition by immune cells. Evidence from clinical and pre-clinical trials supports the use of metronomic delivery for drug-loaded nanoparticles. This review focuses on the functionalization of nanoparticles for improved drug delivery and inhibition of tumor growth. It emphasizes the mechanisms of metronomic chemotherapy and its conjunction with nanotechnology. Additionally, it explores tumor progression and the current methods of chemotherapy. The challenges associated with nano-based metronomic chemotherapy are outlined, paving the way for prospects in this dynamic field.

A propensity score-weighted study comparing a two- versus four-weekly pegylated liposomal doxorubicin regimen in metastatic breast cancer

PURPOSE

A 4-weekly schedule of pegylated liposomal doxorubicin (PLD) has been approved for the treatment of metastatic breast cancer (MBC). Phase II trials have suggested interest in a 2-weekly regimen. This study aimed to compare the efficacy and safety of these two schedules.

METHODS

Data from MBC patients treated with PLD between 2011 and 2021 were retrospectively collected. The objective was to demonstrate the noninferiority of the 2-weekly versus the 4-weekly schedule in terms of 6-month progression-free survival (PFS). The prespecified noninferiority margin was calculated as 1.20. A propensity score to receive either schedule was estimated using a gradient boosting algorithm. Survival analyses using Cox regression models weighted by the propensity score were performed to compare the schedules.

RESULTS

Among the 192 patients included, 96 (50%) underwent each schedule. The median number of previous systemic therapies was 4 (IQR, 3 to 6). Anthracyclines were previously given in early breast cancer in 63.9% of patients. The median follow-up was 10.0 months (IQR, 5.0 to 20.1). A comparable distribution of adverse events was observed. The median PFS was 3.2 months (95% CI, 2.9 to 3.9), and the median overall survival was 12.1 months (95% CI, 10.8 to 14.9). The weighted hazard ratio for PFS was 1.12 (90% CI, 0.82 to 1.54), including the noninferiority boundaries.

CONCLUSION

PLD appeared to be a well-tolerated drug in this heavily pretreated MBC population. The efficacy and safety of the 2-weekly schedule did not provide any advantage, suggesting no interest in changing the registered regimen.

A novel oral metronomic chemotherapy provokes tumor specific immunity resulting in colon cancer eradication in combination with anti-PD-1 therapy

In this study, we investigated the immune-modulating effects of a novel metronomic chemotherapy (MCT) featuring combined oral oxaliplatin (OXA) and pemetrexed (PMX) for colon cancer. OXA and PMX were ionically complexed with lysine derivative of deoxycholic acid (DCK), and incorporated into nanoemulsions or colloidal dispersions, yielding OXA/DCK-NE and PMX/DCK-OP, respectively, to improve their oral bioavailabilities. MCT was not associated with significant lymphotoxicity whereas the maximum tolerated dose (MTD) afforded systemic immunosuppression. MCT was associated with more immunogenic cell death and tumor cell MHC-class I expression than was MTD. MCT improved the tumor antigen presentation of dendritic cells and increased the number of functional T cells in the tumor. MCT also helped to enhance antigen-specific memory responses both locally and systemically. By combining MCT with anti-programmed cell death protein-1 (αPD-1) therapy, the tumor volume was suppressed by 97.85 ± 84.88% compared to the control, resulting in a 95% complete response rate. Upon re-challenge, all tumor-free mice rejected secondary tumors, indicating the induction of a tumor specific memory response. Thus, MCT using an OXA and PMX combination, together with αPD-1, successfully treated colon cancer by activating both innate and adaptive immune cells and elicited tumor-specific long-term immune memory while avoiding toxicity caused by MTD treatment.

Pegylated Liposomal Doxorubicin (Caelyx®) as Adjuvant Treatment in Early-Stage Luminal B-like Breast Cancer: A Feasibility Phase II Trial

Background: Adjuvant chemotherapy for Luminal B-like breast cancers usually includes anthracycline-based regimens. However, some patients are reluctant to receive chemotherapy because of side-effects, especially alopecia, and ask for a “less intensive” or personalized approach. Patients and methods: We conducted a phase II feasibility trial to evaluate pegylated liposomal doxorubicin (PLD, Caelyx^®) as adjuvant chemotherapy. Patients who received surgery for pT1–3, any N, and luminal B-like early-stage breast cancer (EBC) candidates for adjuvant chemotherapy were included. PLD was administered intravenously at 20 mg/m² biweekly for eight courses. Endocrine therapy was given according to menopausal status. Trastuzumab was administered in HER2-positive disease. The primary endpoint was to evaluate the feasibility of this regimen, defined as the ability of a patient to achieve a relative dose intensity (RDI) of at least 85% of the eight cycles of treatment. Secondary endpoints included adverse events (AEs), tolerability, breast cancer-free survival, disease-free survival, and overall survival. Results: From March 2016 to July 2018, 63 patients were included in the trial. Median age was 49 years (range: 33–76), with mostly pre- and peri-menopausal (65%) and stage I–II (94%). Only 5% of patients had HER2-positive EBC. Median RDI was 100% (range: 12.5–100%; interquartile range, IQR: 87.5–100%). The proportion of patients meeting the primary endpoint was 84% (95% confidence interval, CI: 73–92%). Overall, 55 out of 63 enrolled patients completed treatment (87%, 95% CI: 77–94%). Most common AEs were palmar-plantar erythrodysesthesia (12.2%), fatigue (10.4%), and mucositis (8.5%). Only 13% of patients had G3 AEs. None had alopecia. After a median follow-up of 3.9 years (range: 0.3–4.7) two distant events were observed, and all patients were alive at the date of last visit. Conclusions: The trial successfully met its primary endpoint: the regimen was feasible and well tolerated and could be considered for further evaluation as a treatment option for patients with contraindications to standard anthracyclines or requiring a personalized, less intensive approach.

A Rationally Designed ICAM1 Antibody Drug Conjugate for Pancreatic Cancer

Outcomes for pancreatic cancer (PC) patients remain strikingly poor with a 5-year survival of less than 8% due to the lack of effective treatment modalities. Here, a novel precision medicine approach for PC treatment is developed, which is composed of a rationally designed tumor-targeting ICAM1 antibody-drug conjugate (ADC) with optimized chemical linker and cytotoxic payload, complemented with a magnetic resonance imaging (MRI)-based molecular imaging approach to noninvasively evaluate the efficiency of ICAM1 ADC therapy. It is shown that ICAM1 is differentially overexpressed on the surface of human PC cells with restricted expression in normal tissues, enabling ICAM1 antibody to selectively recognize and target PC tumors in vivo. It is further demonstrated that the developed ICAM1 ADC induces potent and durable tumor regression in an orthotopic PC mouse model. To build a precision medicine, an MRI-based molecular imaging approach is developed that noninvasively maps the tumoral ICAM1 expression that can be potentially used to identify ICAM1-overexpressing PC patients. Collectively, this study establishes a strong foundation for the development of a promising ADC to address the critical need in the PC patient care.

Metronomic chemotherapy of cyclophosphamide plus methotrexate for advanced breast cancer: Real-world data analyses and experience of one center

Background

Real‐world data of the CM regimen [cyclophosphamide (CTX) plus methotrexate (MTX)] in metronomic pattern for advanced breast cancer is limited to small‐sample or retrospective studies. This study was aimed to determine the effectiveness and safety of CM regimen in treating advanced breast cancer and to identify which patients are most likely to benefit from metronomic CM regimen.

Methods

Patients with advanced breast cancer who received the metronomic CM regimen at least once between January 2009 and February 2019 in Sun Yat‐sen University Cancer Center were included. Clinicopathological characteristics were collected. Overall survival (OS) and progression‐free survival (PFS) were assessed using Kaplan‐Meier estimates. Characteristics between patients with PFS < 6 months and ≥6 months were compared using the Chi‐square test. Univariate and multivariate Cox regression model was used to estimate the prognostic factors for PFS and OS.

Results

A total of 186 patients were included. The median age and follow‐up were 49 years and 13.3 months, respectively. Over 50% of the patients were estrogen receptor/progesterone receptor‐positive, and 60.8% had been heavily treated (≥3 lines). The objective response rate was 3.8%, the disease control rate at 12 weeks was 41.4%, and the clinical benefit rate at 24 weeks was 31.2% (58/186). The median PFS was 4.0 months [95% confidence interval (CI): 3.6‐4.7 months], the median duration of clinical benefit was 9.5 months (95% CI: 8.2‐10.8 months), and the median OS was 26.8 months (95% CI: 20.9‐37.7 months). Multivariate analysis for PFS revealed the CM regimen as maintenance therapy and no liver metastasis as favorable prognostic factors. Furthermore, patients without liver metastasis were more likely to have a PFS over 6 months than those with liver involvement (P = 0.022). Liver, lymph node, and brain metastases were unfavorable prognostic factors for OS. The CM regimen was well‐tolerated without newly reported adverse events.

Conclusions

The CM regimen was effective in selected patients. In clinical practice, it would be better used as maintenance therapy and in patients without liver metastasis. Further follow‐up investigation should be performed to examine its effect when used in combination with other treatments and determine predictive biomarkers.

Potentiation of Low-Dose Doxorubicin Cytotoxicity by Affecting P-Glycoprotein through Caryophyllane Sesquiterpenes in HepG2 Cells: an in Vitro and in Silico Study

Doxorubicin represents a valuable choice for different cancers, although the severe side effects occurring at the high effective dose limits its clinical use. In the present study, potential strategies to potentiate low-dose doxorubicin efficacy, including a metronomic schedule, characterized by a short and repeated exposure to the anticancer drug, and the combination with the natural chemosensitizing sesquiterpenes β-caryophyllene and β-caryophyllene oxide, were assessed in human hepatoma HepG2 cells. The involvement of P-glycoprotein (P-gp) in the HepG2–chemosensitization to doxorubicin was evaluated. Also, the direct interaction of caryophyllene sesquiterpenes with P-gp was characterized by molecular docking and dynamic simulation studies. A metronomic schedule allowed us to enhance the low-dose doxorubicin cytotoxicity and the combination with caryophyllane sesquiterpenes further potentiated this effect. Also, an increased intracellular accumulation of doxorubicin and rhodamine 123 induced by caryophyllane sesquiterpenes was found, thus suggesting their interference with P-gp function. A lowered expression of P-gp induced by the combinations, with respect to doxorubicin alone, was observed too. Docking studies found that the binding site of caryophyllane sesquiterpene was next to the ATP binding domain of P-gp and that β-caryophyllene possessed the stronger binding affinity and higher inhibition potential calculated by MM-PBSA. Present findings strengthen our hypothesis about the potential chemosensitizing power of caryophyllane sesquiterpenes and suggest that combining a chemosensitizer and a metronomic schedule can represent a suitable strategy to overcome drawbacks of doxorubicin chemotherapy while exploiting its powerful activity.

Treatment of advanced breast cancer with a metronomic schedule of oral vinorelbine: what is the opinion of Italian oncologists?

BACKGROUND

The aim of this study was to record the opinions of Italian oncologists about the use of oral vinorelbine administered metronomically in patients with advanced breast cancer.

METHODS

A series of meetings were held throughout Italy, and participants were asked how much they agreed with each of the several statements.

RESULTS

The majority of oncologists agreed that the concept of the minimum biologically effective dose should be used for drugs administered metronomically. Over 50% agreed that metronomic vinorelbine is an option in first-line chemotherapy for patients with advanced breast cancer, including those with a terminal illness and the elderly, as well as in young and fit patients. Just over one-third of experts agreed that a combination of two chemotherapy agents instead of one is not desirable in metastatic breast cancer because of increased toxicity. Most experts agreed that the main aim of a first-line therapy is to control the disease over time and to preserve quality of life.

CONCLUSION

Metronomically administered oral vinorelbine, either as monotherapy or in combination with other drugs, is effective in the long-term treatment of patients with advanced breast cancer. The clinical profiles of patients should be carefully considered to determine the appropriate treatment strategy.

Metronomics in the neoadjuvant and adjuvant treatment of breast cancer

The concept of metronomic chemotherapy (MC) has evolved from a descriptive preclinical phenomenon encompassing inhibition of angiogenesis to a clinically validated treatment concept involving multiple potential mechanisms of action. Clinicians are progressively more incline to consider MC as a component of mainstream medical oncology practice in advanced breast cancer. However, more recently MC has been tested even in the adjuvant/neoadjuvant setting, taking the opportunity to obtain tumor specimens and blood samples, in order to identify tumor-specific or patient-specific biomarkers for personalizing treatments. In addition, the antiangiogenic and pro-immune nature of metronomic chemotherapy made triple negative breast cancer (TNBC) a good candidate for exploring low-dose maintenance treatment in the adjuvant setting or in combination with immunomodulatory drugs. The potential development of MC in breast cancer pass through the research to identify biomarkers and individual tumor characteristics that can better address the use of this treatment strategy in the future. Finally, the subjective attitude of patients represents one of the major factors that influence the choice and acceptance of a therapeutic program. Personal preference and considerations about quality of life should guide the treatment choice eventually prioritizing the use of MC. Nevertheless, more robust data from randomized phase III trials are needed in the future, in order to make clinicians more confident in using metronomic strategies.

Metronomic chemotherapy and nanocarrier platforms

The therapeutic concept of administering chemotherapeutic agents continuously at lower doses, relative to the maximum tolerated dose (MTD) without drug-free breaks over extended periods -known as "metronomic chemotherapy"- is a promising approach for anti-angiogenic cancer therapy. In comparison with MTD chemotherapy regimens, metronomic chemotherapy has demonstrated reduced toxicity. However, as a monotherapy, metronomic chemotherapy has failed to provide convincing results in clinical trials. Therapeutic approaches including combining the anti-angiogenic "metronomic" therapy with conventional radio-/chemo-therapy and/or targeted delivery of chemotherapeutic agents to tumor tissues via their encapsulation with nanocarrier-based platforms have proven to potentiate the overall therapeutic outcomes. In this review, therefore, we focused on the mutual contribution made by nanoscale drug delivery platforms to the therapeutic efficacy of metronomic-based chemotherapy. In addition, the influence that the dosing schedule has on the overall therapeutic efficacy of metronomic chemotherapy is discussed.

Biweekly Pegylated Liposomal Doxorubicin (Caelyx) in Heavily Pretreated Metastatic Breast Cancer: A Phase 2 Study

BACKGROUND

Pegylated liposomal doxorubicin (PLD) has shown to be as effective as conventional doxorubicin in the treatment of metastatic breast cancer but provides a lower risk of cardiotoxicity. This phase 2 study in heavily pretreated patients with metastatic breast cancer was initiated to evaluate a biweekly instead of a 4-week schedule of PLD in order to obtain a more flexible and tolerable regimen.

PATIENTS AND METHODS

A total of 25 patients with 2 or more prior lines of chemotherapy for metastatic disease were treated with PLD (25 mg/m²) at 2-week intervals for a maximum of 12 courses. Pretreatment with anthracyclines was allowed as long as the cumulative doxorubicin dose at study entry was below 400 mg/m². Most patients were pretreated with anthracyclines, taxanes, vinorelbine, alkylating agents, and capecitabine.

RESULTS

The clinical benefit rate, ie, objective response or stable disease, for at least 6 months was 22.7% for all patients and 22.2% in anthracycline- and taxane-pretreated patients, respectively. Median duration of clinical benefit and median time to progression were 12.5 months (95% confidence interval [CI], 10.1-32.3) and 7 weeks (95% CI, 5.4-8.6), respectively. Median overall survival was 9.6 months (95% CI, 5.4-13.9). One- and 2-year survival rates were 38% and 4%, respectively. Myelosuppression was low, with no grade 3 or 4 neutropenia or thrombocytopenia. Most common nonhematologic toxicities were nausea, alopecia, asthenia, and hand-foot syndrome. The low rate of hematologic toxicity and hand-foot syndrome is clinically noteworthy.

CONCLUSION

Biweekly PLD is an easily manageable schedule with a favorable toxicity profile. Efficacy was moderate in heavily pretreated patients.

Dose-Dense Chemotherapy in Metastatic Breast Cancer: Shortening the Time Interval for a Better Therapeutic Index

Despite the advancement of targeted therapies in metastatic breast cancer, chemotherapy is still of pivotal importance. The concept of dose density is known to increase the efficacy of chemotherapy. In metastatic disease, preservation of the quality of life is equally important. Because of this, weekly regimens are a cornerstone in metastatic disease. Taxanes like paclitaxel or nab-paclitaxel as well as antracyclines are often used in palliative treatment. Further advances to increase dose density have led to the concept of daily metronomic schedules with oral chemotherapeutic drugs like cyclophosphamide, capecitabine, or vinorelbine. Metronomic chemotherapy affects tumor angiogenesis and also weakens immunosuppressive regulatory T cells, promoting better control of tumor progression. Weekly or daily dose-dense regimens are a reasonable compromise between efficacy and toxicity to improve the therapeutic index. This is most important for the treatment of chronic disease where palliation and preservation of quality of life are vital.

Two repeated low doses of doxorubicin are more effective than a single high dose against tumors overexpressing P-glycoprotein

Standard chemotherapeutic protocols, based on maximum tolerated doses, do not prevent nor overcome chemoresistance caused by the efflux transporter P-glycoprotein (Pgp). We compared the effects of two consecutive low doses versus a single high dose of doxorubicin in drug-sensitive Pgp-negative and drug-resistant Pgp-positive human and murine cancer cells. Two consecutive low doses were significantly more cytotoxic in vitro and in vivo against drug-resistant tumors, while a single high dose failed to do so. The greater efficacy of two consecutive low doses of doxorubicin could be linked to increased levels of intracellular reactive oxygen species. These levels were produced by high electron flux from complex I to complex III of the mitochondrial respiratory chain, unrelated to the synthesis of ATP. This process induced mitochondrial oxidative damage, loss of mitochondrial potential and activation of the cytochrome c/caspase 9/caspase 3 pro-apoptotic axis in drug-resistant cells. Our work shows that the "apparent" ineffectiveness of doxorubicin against drug-resistant tumors overexpressing Pgp can be overcome by changing the timing of its administration and its doses.

Metronomic chemotherapy from rationale to clinical studies: a dream or reality?

Metronomic chemotherapy (MC) refers to the close administration of a chemotherapeutic drug for a long time with no extended drug-free breaks. It was developed to overcome drug resistance, partly by shifting the therapeutic target from tumor cells to the tumor vasculature, with less toxicity. Because of this peculiar way of administration, MC can be viewed as a form of long-term 'maintenance' treatment, and can be integrated with standard and conventional chemotherapy in a "chemo-switching" strategy. Additional mechanisms are involved in its antitumor activity, such as activation of immunity, induction of tumor dormancy, chemotherapy-driven dependency of cancer cells, and the '4D effect'. In this paper we report the most important studies that have analyzed these processes. In fact, a number of preclinical and clinical studies in solid tumors as well as in multiple myeloma, have been reported regarding several chemotherapy drugs which have been proposed with a metronomic schedule: vinorelbine, cyclophosphamide, capecitabine, methotrexate, bevacizumab, etoposide, gemcitabine, sorafenib, everolimus and temozolomide. The results of these studies have been sometimes conflicting, highlighting the need to develop reliable tools for patient selection and stratification. However, a more precise evaluation of MC strategies with the ongoing randomized phase II/III clinical is fundamental, because of the strict correlation of this approach with translational research and target therapy. Moreover, because of the low toxicity of MC, these studies will also help to better evaluate the clinical benefit of this treatment, with a special focus on elderly and low performance status patients.

Metronomic therapy and breast cancer: a systematic review

Metronomic therapy (MT) refers to repetitive, low doses of chemotherapy drugs. MT exerts an effect not only on tumour cells, but also on their microenvironment. In particular, the low-dose schedule compromises the repairing process of endothelial cells, leading to an anti-angiogenic effect. In addition to the anti-angiogenic effect, MT could have an immunological action through the restoration of the anticancer effect of the immune system and induction of tumour dormancy. Consequently the association of targeted therapy with anti-angiogenic properties or specific immunologic drugs could enhance the efficacy of MT. During the past 15 years, several studies have been published evaluating the metronomic strategy in breast cancer. We conducted a systematic review of the results of phase I, II and III studies testing MT in breast cancer patients. The analyses included the efficacy and toxicity data of MT, and the future development of this strategy in breast cancer are also discussed. The systematic review presented here suggests that MT is a treatment option for breast cancer patients, has a low toxicity profile, efficacy in most patients and has potentially significant cost-effective advantages for public health.

Adjuvant pegylated liposomal doxorubicin for older women with endocrine nonresponsive breast cancer who are NOT suitable for a "standard chemotherapy regimen": the CASA randomized trial

There is no optimal treatment for breast cancers lacking estrogen (ER) and progesterone (PgR) receptors in elderly women with co-morbidities that prevent use of "standard chemotherapy regimens" such as AC or CMF. The CASA trial studied pegylated liposomal doxorubicin (PLD) and low dose, metronomic cyclophosphamide + methotrexate (CM) for older (>65), vulnerable women with operable, ER and PgR-negative breast cancer. After two years the trial closed early, due to slow and inadequate accrual, with 77 patients (38:PLD, 36:CM, 3:nil). Sixty-eight percent completed PLD; 83% completed CM (both 16 weeks). Patients on PLD reported worse quality of life, cognitive and physical functioning than non-PLD regimens (primarily CM). At a median follow-up of 42 months, 81% of randomized patients remained free of any breast cancer recurrence. Based on our limited experience, PLD and CM may be reasonable options for further study for elderly vulnerable patients with endocrine nonresponsive breast cancer.

Overcoming evasive resistance from vascular endothelial growth factor a inhibition in sarcomas by genetic or pharmacologic targeting of hypoxia-inducible factor 1α

Increased levels of hypoxia and hypoxia-inducible factor 1α (HIF-1α) in human sarcomas correlate with tumor progression and radiation resistance. Prolonged antiangiogenic therapy of tumors not only delays tumor growth but may also increase hypoxia and HIF-1α activity. In our recent clinical trial, treatment with the vascular endothelial growth factor A (VEGF-A) antibody, bevacizumab, followed by a combination of bevacizumab and radiation led to near complete necrosis in nearly half of sarcomas. Gene Set Enrichment Analysis of microarrays from pretreatment biopsies found that the Gene Ontology category “Response to hypoxia” was upregulated in poor responders and that the hierarchical clustering based on 140 hypoxia-responsive genes reliably separated poor responders from good responders. The most commonly used chemotherapeutic drug for sarcomas, doxorubicin (Dox), was recently found to block HIF-1α binding to DNA at low metronomic doses. In four sarcoma cell lines, HIF-1α shRNA or Dox at low concentrations blocked HIF-1α induction of VEGF-A by 84–97% and carbonic anhydrase 9 by 83–93%. HT1080 sarcoma xenografts had increased hypoxia and/or HIF-1α activity with increasing tumor size and with anti-VEGF receptor antibody (DC101) treatment. Combining DC101 with HIF-1α shRNA or metronomic Dox had a synergistic effect in suppressing growth of HT1080 xenografts, at least in part via induction of tumor endothelial cell apoptosis. In conclusion, sarcomas respond to increased hypoxia by expressing HIF-1α target genes that may promote resistance to antiangiogenic and other therapies. HIF-1α inhibition blocks this evasive resistance and augments destruction of the tumor vasculature.

Nanoparticle delivery strategies to target doxorubicin to tumor cells and reduce side effects

Doxorubicin (DOX) is one of the most active anticancer drugs, while its cumulative dose-dependent side effects compromise the anticancer efficacy. Nanoparticles, an emerging platform for cancer therapy, have been shown to increase intracellular uptake of DOX with reduced side effects compared with conventional DOX formulations. While large numbers of clinical and preclinical studies have been published, the purpose of this review is to draw attention to the developments of DOX-loaded nanoparticles for cancer therapy, with special a focus on enhanced intracellular uptake and reduced side-effects strategies.