Extended topoisomerase 1 inhibition through liposomal irinotecan results in improved efficacy over topotecan and irinotecan in models of small-cell lung cancer

Survival predictors in patients with pancreatic cancer on liposomal irinotecan plus fluorouracil/leucovorin: a multicenter observational study

Background

Approximately half of the patients with advanced pancreatic ductal adenocarcinoma (PDAC) receive subsequent lines of chemotherapy. Recently, the liposomal irinotecan (nal-IRI) plus 5-fluorouracil/leucovorin (5-FU/LV) regimen is recommended as subsequent lines of chemotherapy. However, little is known about the predictive factors for the nal-IRI + 5-FU/LV regimen, especially in patients with previous irinotecan (IRI) exposure.

Objectives

We investigated the predictive factors associated with nal-IRI + 5-FU/LV treatment in patients with PDAC.

Design

Multicenter, retrospective cohort study.

Methods

This study included patients with advanced PDAC who received the nal-IRI + 5-FU/LV regimen for palliative purposes.

Results

Overall, 268 patients were treated with nal-IRI + 5-FU/LV. The median overall survival (OS) was 7.9 months (95% confidence interval (CI): 7.0-8.8), while the median progression-free survival (PFS) was 2.6 months (95% CI: 1.9-3.2). An albumin level of<4.0 g/dL, neutrophil-to-lymphocyte ratio (NLR) of ⩾3.5, liver or peritoneal metastasis, and a history of >3 lines of palliative chemotherapy were associated with worse OS. An NLR of ⩾3.5 and liver metastasis were significant predictive factors for worse PFS. Previous exposure to IRI was not a significant predictor. Patients without prior IRI (no-IRI) treatment showed relatively longer OS and PFS compared to IRI responders and nonresponders, but these differences were not significant when compared specifically to the responders (OS: 8.8 vs 8.1 months, p = 0.388; PFS: 3.6 vs 2.6 months, p = 0.126).

Conclusion

An NLR of ⩾3.5 and liver metastasis were associated with worse PFS. Prior IRI exposure was not a significant predictive factor for OS and PFS, especially in IRI responders.

Minocycline and photodynamic priming significantly improve chemotherapy efficacy in heterotypic spheroids of pancreatic ductal adenocarcinoma

The prognosis for patients with advanced-stage pancreatic ductal adenocarcinoma (PDAC) remains dismal. It is generally accepted that combination cancer therapies offer the most promise, such as Folforinox, despite their associated high toxicity. This study addresses the issue of chemoresistance by introducing a complementary dual priming approach to attenuate the DNA repair mechanism and to improve the efficacy of a type 1 topoisomerase (Top1) inhibitor. The result is a regimen that integrates drug-repurposing and nanotechnology using 3 clinically relevant FDA-approved agents (1) Top1 inhibitor (irinotecan) at subcytotoxic doses (2) benzoporphyrin derivative (BPD) as a photoactive molecule for photodynamic priming (PDP) to improve the delivery of irinotecan within the cancer cell and (3) minocycline priming (MNP) to modulate DNA repair enzyme Tdp1 (tyrosyl-DNA phosphodiesterase) activity. We demonstrate in heterotypic 3D cancer models that incorporate cancer cells and pancreatic cancer-associated fibroblasts that simultaneous targeting of Tdp1 and Top1 were significantly more effective by employing MNP and photoactivatable multi-inhibitor liposomes encapsulating BPD and irinotecan compared to monotherapies or a cocktail of dual or triple-agents. These data are encouraging and warrant further work in appropriate animal models to evolve improved therapeutic regimens.

Drug Stability and Minimized Acid-/Drug-Catalyzed Phospholipid Degradation in Liposomal Irinotecan

Therapeutics at or close to the nanoscale, such as liposomal irinotecan, offer significant promise for the treatment of solid tumors. Their potential advantage over the unencapsulated or free form of the drug is due in part to their altered biodistribution. For slow and sustained release, significant optimization of formulation is needed to achieve the required level of stability and allow long-term storage of the drug product. Gradient-based liposomal formulation of camptothecins such as irinotecan poses unique challenges owing to the camptothecin- and acid-catalyzed hydrolysis of phospholipid esters in the inner monolayer of the liposomal membrane. We demonstrated that a narrow set of conditions related to the external pH, temperature, intraliposomal concentration, identity of the drug-trapping agent, physical form of the drug inside the liposomes, and final drug load have a marked impact on the stability of the liposome phospholipid membrane. The physical form of the drug inside the liposome was shown to be an insoluble gel with an irinotecan-to-sulfate ratio approximating 1:1, reducing the potential for irinotecan-catalyzed phospholipid hydrolysis in the internal phospholipid monolayer. As a result of this work, a stable and active liposome formulation has been developed that maintains phospholipid chemical stability following long-term storage at 2-8°C.

A Multicenter Phase 1 Trial Evaluating Nanoliposomal Irinotecan for Heated Intraperitoneal Chemotherapy Combined with Cytoreductive Surgery for Patients with Peritoneal Surface Disease

BACKGROUND

Nanoliposomal irinotecan (nal-IRI) is a promising novel hyperthermic intraperitoneal chemotherapy (HIPEC) agent given its enhanced efficacy against gastrointestinal tumors, safety profile, thermo-synergy, and heat stability. This report describes the first in-human phase 1 clinical trial of nal-IRI during cytoreductive surgery (CRS) and HIPEC.

METHODS

Patients with peritoneal surface disease (PSD) from appendiceal and colorectal neoplasms were enrolled in a 3 + 3 dose-escalation trial using nal-IRI (70-280 mg/m²) during HIPEC for 30 min at 41 ± 1 °C. The primary outcome was safety. The secondary outcomes were pharmacokinetics (PK) and disease-free survival. Adverse events (AEs) categorized as grade 2 or higher were recorded. The serious AEs (SAEs) were mortality, grade ≥ 3 AEs, and dose-limiting toxicity (DLT). Irinotecan and active metabolite SN38 were measured in plasma and peritoneal washings.

RESULTS

The study enrolled 18 patients, who received nal-IRI during HIPEC at 70 mg/m² (n = 3), 140 mg/m² (n = 6), 210 mg/m² (n = 3), and 280 mg/m² (n = 6). No DLT or mortality occurred. The overall morbidity for CRS/HIPEC was 39% (n = 7). Although one patient experienced neutropenia, no AE (n = 131) or SAE (n = 3) was definitively attributable to nal-IRI. At 280 mg/m², plasma irinotecan and SN38 measurements showed maximum concentrations of 0.4 ± 0.6 µg/mL and 3.0 ± 2.4 ng/mL, a median time to maximum concentration of 24.5 and 26 h, and areas under the curve of 22.6 h*µg/mL and 168 h*ng/mL, respectively. At the 6-month follow-up visit, 83% (n = 15) of the patients remained disease-free.

CONCLUSIONS

In this phase 1 HIPEC trial (NCT04088786), nal-IRI was observed to be safe, and PK profiling showed low systemic absorption overall. These data support future studies testing the efficacy of nal-IRI in CRS/HIPEC.

The Development of Investigator-Initiated Clinical Trials in Surgical Oncology

Investigator-initiated trials (IITs) are designed by principal investigators who identify important, unaddressed clinical gaps and opportunities to answer these questions through clinical trials. Surgical oncologists are poised to lead IITs due to their multidisciplinary clinical practice and substantial research background. The process of developing, organizing, and implementing IITs is multifaceted and involves important steps including (but not limited to) navigating regulatory requirements, obtaining funding, and meeting enrollment targets. Here, the authors explore the steps, methodology, and barriers of IIT development by surgical oncologists and highlight the importance of IITs in oncology.

Augmenting Experimental Gastric Cancer Activity of Irinotecan through Liposomal Formulation and Antiangiogenic Combination Therapy

Gastric adenocarcinoma (GAC) is the third most common cause of cancer-related deaths worldwide. Combination chemotherapy remains the standard treatment for advanced GAC. Liposomal irinotecan (nal-IRI) has improved pharmacokinetics (PK) and drug biodistribution compared with irinotecan (IRI, CPT-11). Angiogenesis plays a crucial role in the progression and metastasis of GAC. We evaluated the antitumor efficacy of nal-IRI in combination with novel antiangiogenic agents in GAC mouse models. Animal survival studies were performed in peritoneal dissemination xenografts. Tumor growth and PK studies were performed in subcutaneous xenografts. Compared with controls, extension in animal survival by nal-IRI and IRI was >156% and >94%, respectively. The addition of nintedanib or DC101 extended nal-IRI response by 13% and 15%, and IRI response by 37% and 31% (MKN-45 xenografts); nal-IRI response by 11% and 3%, and IRI response by 16% and 40% (KATO-III xenografts). Retardation of tumor growth was greater with nal-IRI (92%) than IRI (71%). Nintedanib and DC101 addition tend to augment nal-IRI or IRI response in this model. The addition of antiangiogenic agents enhanced tumor cell proliferation inhibition effects of nal-IRI or IRI. The tumor vasculature was decreased by nintedanib (65%) and DC101 (58%), while nal-IRI and IRI alone showed no effect. PK characterization in GAC xenografts demonstrated that compared with IRI, nal-IRI treatment groups had higher retention, circulation time, and tumor levels of CPT-11 and its active metabolite SN-38. These findings indicate that nal-IRI, alone and in combination with antiangiogenic agents, has the potential for improving clinical GAC therapy.

Liposomal irinotecan (Onivyde): Exemplifying the benefits of nanotherapeutic drugs

Irinotecan is a topoisomerase inhibitor, widely used in treatment of malignancies including pancreatic ductal adenocarcinoma (PDAC) as part of the FOLFIRINOX regimen prescribed as a first-line treatment in several countries. However, irinotecan has not been successfully introduced as a second-line treatment for pancreatic cancer and few randomized clinical studies have evaluated its added value. Efficacy of liposomal irinotecan (nal-IRI) combined with 5-fluorouracil and leucovorin (5-FU/LV) was reported in the phase III NAPOLI-1 trial in metastatic PDAC following failure of gemcitabine-based therapy. Several features of nal-IRI pharmacokinetics (PK) could result in better outcomes versus nonliposomal irinotecan. Irinotecan is a prodrug that is converted to active SN-38 by carboxylesterase enzymes and inactivated by cytochrome P450 3A4/3A5. SN-38 is inactivated by UGT1A1 enzymes. Individual variations in their expression and activity could influence enhanced localized irinotecan activity and toxicity. Liposomal irinotecan exploits the enhanced permeability and retention effect in cancer, accumulating in tumor tissues. Liposomal irinotecan also has a longer half-life and higher area under the concentration-time curve (0-∞) than nonliposomal irinotecan, as the liposomal formulation protects cargo from premature metabolism in the plasma. This results in irinotecan activation in tumor tissue, leading to enhanced cytotoxicity. Importantly, despite the longer exposure, overall toxicity for nal-IRI is no worse than nonliposomal irinotecan. Liposomal irinotecan exemplifies how liposomal encapsulation of a chemotherapeutic agent can alter its PK properties, improving clinical outcomes for patients. Liposomal irinotecan is currently under investigation in other malignancies including biliary tract cancer (amongst other gastrointestinal cancers), brain tumors, and small-cell lung cancer.

A novel NCI-H69V small cell lung cancer functional mini-tumor model for future treatment screening applications

Small cell lung cancer (SCLC) is aggressive and despite multiple clinical trials, its standard of care is unchanged for the past three decades. In vitro cancer models are crucial in chemotherapy development, and three-dimensional (3D) models aim to bridge the gap between two-dimensional (2D) flat cultures and in vivo testing. Functional 3D spheroids can better represent the in vivo situation and tumor characteristics than 2D models. An NCI-H69V SCLC mini-tumor model was developed in a clinostat-based rotating bioreactor system. Spheroid growth and viability were characterized for 30 days, and the ideal experimental window with mature and metabolically stable spheroids was determined. Application of the model for anticancer treatment screening was validated with the standard chemotherapeutic drug irinotecan, for an exposure period of 72 h. The following parameters were measured: soluble protein content, planar surface area measurements, intracellular adenosine triphosphate and extracellular adenylate kinase levels, and glucose consumption. Histological morphology of the spheroids was observed. The established model proved viable and stable, while treatment with irinotecan caused a decrease in cell growth, viability, and glucose consumption demonstrating reactivity of the model to chemotherapy. Therefore, this NCI-H69V SCLC functional spheroid model could be used for future anticancer compound screening.

Topoisomerase 1 inhibition modulates pyroptosis to improve recovery after spinal cord injury

Excessive neuroinflammation and neuronal loss contribute to mechanisms of spinal cord injury (SCI). Accumulating evidence has suggested that topoisomerase 1 (Top1) inhibition can suppress exacerbated immune responses and protect against lethal inflammation. Pyroptosis is a recently identified pro-inflammatory programmed mode of cell death. However, the effects and underlying mechanisms of Top1 inhibition in SCI remains unclear. Locomotor functional recovery in mice was evaluated through Basso Mouse Scale (BMS). Neuronal loss was evaluated by immunochemistry staining of NeuN. Pyroptosis was determined by immunofluorescence staining, western blot, flow cytometry, cell viability, and cytotoxicity assays. In the present study, we estimated the effects of chemical inhibition of Top1 in an SCI model. Administration of Top1 inhibitor camptothecin (CPT) to mice significantly improved locomotor functional recovery after SCI. Moreover, CPT reduced Top1 level, inhibited nucleotide-binding oligomerization domain-like receptor 3 (NLRP3) inflammasome activation and pyroptosis, attenuated proinflammatory cytokines levels, diminished the number of neutrophil and neuronal loss in mice. Furthermore, CPT in oxygen-glucose deprivation neurons down-regulated Top1 level, attenuated NLRP3 inflammasome activation, and suppressed pyroptosis and inflammatory response. Together, our findings indicate that inhibition of Top1 with CPT can inhibit pyroptosis, control neuroinflammation, and improve functional recovery after SCI.

Nanoliposomal irinotecan in combination with leucovorin and 5‑fluorouracil in advanced biliary tract cancers

Biliary tract cancers (BTC) are rare but aggressive. Due to limited anti-tumor effects of current second- and later-line treatment regimens, novel treatment options are required. Nanoliposomal irinotecan in combination with leucovorin and 5-fluorouracil (FOLFnal-IRI) achieved promising results as a second-line treatment in patients with pancreatic cancer, warranting further investigation in BTC. In the present study, a retrospective analysis of patients receiving FOLFnal-IRI after initial platinum-based chemotherapy for advanced BTC between January 2016 and August 2020 at the University Hospital Cologne (Cologne, Germany) was performed. A total of 11 patients were identified who met the inclusion criteria. A total of 4 patients (36.4%) were female and the median age was 54 years. The proportion of patients suffering from gallbladder carcinoma, intrahepatic and extrahepatic cholangiocarcinoma was 18.2, 63.6 and 9.1%, respectively. Furthermore, 7 patients (63.6%) received FOLFnal-IRI as their second-, 3 (27.3%) as third- and one (9.1%) as their fourth-line therapy. The disease control rate was 54.5% and 3 grade III toxicities were recorded. Progression-free survival and overall survival (OS) after initiation of FOLFnal-IRI was 5.1 and 12.4 months, respectively. OS after initial diagnosis was 24.7 months. FOLFnal-IRI demonstrated promising antitumor potential with an acceptable safety profile as a subsequent therapy regimen in advanced biliary tract malignancies. Further randomized controlled trials of its value as a treatment option for BTC appear justified.

Nanoparticles from Gantrez-based conjugates for the oral delivery of camptothecin

Camptothecin (CPT) exhibits a number of challenges for its oral administration, including a low aqueous solubility, a lactone ring susceptible to hydrolysis, and an affinity to the intestinal P-gp. The aim of this work was to evaluate nanoparticles from Gantrez-based conjugates as carriers for the oral delivery of CPT. For this purpose two different conjugates (G-mPEG and G-HPCD), obtained by the covalent binding of either HP-β-CD or methoxy-PEG (m-PEG) to the polymer backbone of Gantrez™ AN, were synthetized and characterized. Both excipients (m-PEG and HPCD) were selected due to their reported abilities to stabilize the lactone ring of CPT and disturb the effect of intestinal P-gp. The resulting nanoparticles (G-mPEG-NP and G-HPCD-NP) presented a similar size (about 200 nm) and zeta potential (close to −35 mV); although, G-mPEG-NP presented a higher CPT payload than G-HPCD-NP. On the contrary, in rats, nanoparticles based on Gantrez conjugates appeared to be capable of crossing the protective mucus layer and reach the intestinal epithelium, whereas conventional Gantrez nanoparticles displayed a mucoadhesive profile. Finally, the pharmacokinetic study revealed that both formulations were able to enhance the relative oral bioavailability of CPT; although this value was found to be 2.6-times higher for G-mPEG-NP than for G-HPCD-NP.

A brain proteomic signature of incipient Alzheimer's disease in young APOE ε4 carriers identifies novel drug targets

Aptamer-based proteomics revealed differentially abundant proteins in Alzheimer’s disease (AD) brains in the Baltimore Longitudinal Study of Aging and Religious Orders Study (mean age, 89 ± 9 years). A subset of these proteins was also differentially abundant in the brains of young APOE ε4 carriers relative to noncarriers (mean age, 39 ± 6 years). Several of these proteins represent targets of approved and experimental drugs for other indications and were validated using orthogonal methods in independent human brain tissue samples as well as in transgenic AD models. Using cell culture–based phenotypic assays, we showed that drugs targeting the cytokine transducer STAT3 and the Src family tyrosine kinases, YES1 and FYN, rescued molecular phenotypes relevant to AD pathogenesis. Our findings may accelerate the development of effective interventions targeting the earliest molecular triggers of AD.

Current Strategies for Extensive Stage Small Cell Lung Cancer Beyond First-line Therapy

Extensive stage small cell lung cancer carries extremely poor prognosis and adding immune checkpoint inhibitor to platinum etoposide combination in first line only improved outcomes modestly. Once disease recurs, treatment response is only transient in nature. Various strategies that are being explored include dual checkpoint blockade, BiTE and CAR-T cell approaches. Immune checkpoint inhibitors are being combined with PARP inhibitors. Other approaches currently being investigated include liposomal irinotecan and combining known active agents for SCLC in relapsed setting such as newly approved lurbinectedin with doxorubicin, paclitaxel, irinotecan or topotecan with ATR inhibitor (Berzosertib). Temozolomide has also been tested in combination with a Parp inhibitor. New antibody or small molecule drug conjugates are being actively investigated, so is a biomarker based approach. Better understanding of small cell lung cancer disease biology via high through-put genomic, proteomic and methylation profiling offer glimpse of hope in our efforts to contain this deadly disease. A table of representative molecular targets under investigation is provided in the end.

Novel Cytotoxic Chemotherapies in Small Cell Lung Carcinoma

Small cell lung cancer (SCLC) is one of the deadliest thoracic neoplasms, in part due to its fast doubling time and early metastatic spread. Historically, cytotoxic chemotherapy consisting of platinum-etoposide or anthracycline-based regimens has demonstrated a high response rate, but early chemoresistance leads to a poor prognosis in advanced SCLC. Only a fraction of patients with limited-disease can be cured by chemo-radiotherapy. Given the disappointing survival rates in advanced SCLC, new cytotoxic agents are eagerly awaited. Unfortunately, few novel chemotherapy drugs have been developed in the latest decades. This review describes the results and potential application in the clinical practice of novel chemotherapy agents for SCLC.

Recent Advancements in Liposome-Targeting Strategies for the Treatment of Gliomas: A Systematic Review

Malignant tumors represent some of the most intractable diseases that endanger human health. A glioma is a tumor of the central nervous system that is characterized by severe invasiveness, blurred boundaries between the tumor and surrounding normal tissue, difficult surgical removal, and high recurrence. Moreover, the blood-brain barrier (BBB) and multidrug resistance (MDR) are important factors that contribute to the lack of efficacy of chemotherapy in treating gliomas. A liposome is a biofilm-like drug delivery system with a unique phospholipid bilayer that exhibits high affinities with human tissues/organs (e.g., BBB). After more than five decades of development, classical and engineered liposomes consist of four distinct generations, each with different characteristics: (i) traditional liposomes, (ii) stealth liposomes, (iii) targeting liposomes, and (iv) biomimetic liposomes, which offer a promising approach to promote drugs across the BBB and to reverse MDR. Here, we review the history, preparatory methods, and physicochemical properties of liposomes. Furthermore, we discuss the mechanisms by which liposomes have assisted in the diagnosis and treatment of gliomas, including drug transport across the BBB, inhibition of efflux transporters, reversal of MDR, and induction of immune responses. Finally, we highlight ongoing and future clinical trials and applications toward further developing and testing the efficacies of liposomes in treating gliomas.

Applications and strategies in nanodiagnosis and nanotherapy in lung cancer

Lung cancer is the second most common cancer and the leading cause of death in both men and women in the world. Lung cancer is heterogeneous in nature and diagnosis is often at an advanced stage as it develops silently in the lung and is frequently associated with high mortality rates. Despite the advances made in understanding the biology of lung cancer, progress in early diagnosis, cancer therapy modalities and considering the mechanisms of drug resistance, the prognosis and outcome still remains low for many patients. Nanotechnology is one of the fastest growing areas of research that can solve many biological problems such as cancer. A growing number of therapies based on using nanoparticles (NPs) have successfully entered the clinic to treat pain, cancer, and infectious diseases. Recent progress in nanotechnology has been encouraging and directed to developing novel nanoparticles that can be one step ahead of the cancer reducing the possibility of multi-drug resistance. Nanomedicine using NPs is continuingly impacting cancer diagnosis and treatment. Chemotherapy is often associated with limited targeting to the tumor, side effects and low solubility that leads to insufficient drug reaching the tumor. Overcoming these drawbacks of chemotherapy by equipping NPs with theranostic capability which is leading to the development of novel strategies. This review provides a synopsis of current progress in theranostic applications for lung cancer diagnosis and therapy using NPs including liposome, polymeric NPs, quantum dots, gold NPs, dendrimers, carbon nanotubes and magnetic NPs.

Liposomal Irinotecan + 5-FU/LV in Metastatic Pancreatic Cancer: Subgroup Analyses of Patient, Tumor, and Previous Treatment Characteristics in the Pivotal NAPOLI-1 Trial

OBJECTIVES

The NAnoliPOsomaL Irinotecan (NAPOLI-1) study (NCT01494506) was the largest global phase 3 study in a post-gemcitabine metastatic pancreatic adenocarcinoma (mPAC) population (N = 417). The subanalyses reported here investigated the prognostic effect of tumor characteristics and disease stage, prior treatment characteristics, baseline patient characteristics on survival outcomes in NAPOLI-1, and whether liposomal irinotecan (nal-IRI) + 5-fluorouracil/leucovorin (5-FU/LV) benefited patients with mPAC across subgroups.

METHODS

Post hoc analyses were performed in the NAPOLI-1 population (4 across tumor characteristics and disease stage, 6 across prior treatment characteristics, and 4 across patient baseline characteristics). Survival outcomes were estimated by Kaplan-Meier analysis and patient safety data were evaluated.

RESULTS

Mortality and morbidity risk was lower on nal-IRI+5-FU/LV treatment across subgroups. Exceptions were patients who had received prior nonliposomal irinotecan and those who had undergone prior Whipple procedure (overall survival hazard ratio = 1.25 and 1.23, respectively). Decreased appetite, liver metastases, and number of measurable metastatic lesions seemed to be prognostic of survival in this population. Subgroup safety data were generally comparable with those in the overall NAPOLI-1 safety population.

CONCLUSIONS

A diverse population of patients with mPAC that progressed on gemcitabine-based therapy benefited from nal-IRI+5-FU/LV versus 5-FU/LV, potentially helping guide treatment decisions for challenging cases.

Potent Antitumor Activity of Liposomal Irinotecan in an Organoid- and CRISPR-Cas9-Based Murine Model of Gallbladder Cancer

Gallbladder cancer is associated with a dismal prognosis, and accurate in vivo models will be elemental to improve our understanding of this deadly disease and develop better treatment options. We have generated a transplantation-based murine model for gallbladder cancer that histologically mimics the human disease, including the development of distant metastasis. Murine gallbladder–derived organoids are genetically modified by either retroviral transduction or transfection with CRISPR/Cas9 encoding plasmids, thereby allowing the rapid generation of complex cancer genotypes. We characterize the model in the presence of two of the most frequent oncogenic drivers—Kras and ERBB2—and provide evidence that the tumor histology is highly dependent on the driver oncogene. Further, we demonstrate the utility of the model for the preclinical assessment of novel therapeutic approaches by showing that liposomal Irinotecan (Nal-IRI) is retained in tumor cells and significantly prolongs the survival of gallbladder cancer–bearing mice compared to conventional irinotecan.

Topoisomerase inhibitors: Pharmacology and emerging nanoscale delivery systems

Topoisomerase enzymes have shown unique roles in replication and transcription. These enzymes which were initially found in Escherichia coli have attracted considerable attention as target molecules for cancer therapy. Nowadays, there are several topoisomerase inhibitors in the market to treat or at least control the progression of cancer. However, significant toxicity, low solubility and poor pharmacokinetic properties have limited their wide application and these characteristics need to be improved. Nano-delivery systems have provided an opportunity to modify the intrinsic properties of molecules and also to transfer the toxic agent to the target tissues. These delivery systems leads to the re-introduction of existing molecules present in the market as novel therapeutic agents with different physicochemical and pharmacokinetic properties. This review focusses on a variety of nano-delivery vehicles used for the improvement of pharmacological properties of topoisomerase inhibitors and thus enabling their potential application as novel drugs in the market.

Irinotecan: 25 years of cancer treatment

Twenty-five years ago, the cytotoxic drug irinotecan (IRT) was first approved in Japan for the treatment of cancer. For more than two decades, the IRT prodrug has largely contributed to the treatment of solid tumors worldwide. Nowadays, this camptothecin derivative targeting topoisomerase 1 remains largely used in combination regimen, like FOLFIRI and FOLFIRINOX, to treat metastatic or advanced solid tumors, such as colon, gastric and pancreatic cancers and others. This review highlights recent discoveries in the field of IRT and its derivatives, including analogues of the active metabolite SN38 (such as FL118), the recently approved liposomal form Nal-IRI and SN38-based immuno-conjugates currently in development (such as sacituzumab govitecan). New information about the IRT mechanism of action are presented, including the discovery of a new protein target, the single-stranded DNA-binding protein FUBP1. Significant progress has been made also to better understand and manage the main limiting toxicities of IRT, chiefly neutropenia and diarrhea. The role of drug-induced inflammation and dysbiosis is underlined and strategies to limit the intestinal toxicity of IRT are discussed (use of β-glucuronidase inhibitors, plant extracts, probiotics). The detailed knowledge of the metabolism of IRT has enabled the identification of potential biomarkers to guide patient selection and to limit drug-induced toxicities, but no robust IRT-specific therapeutic biomarker has been approved yet. IRT is a versatile chemotherapeutic agent which combines well with a variety of anticancer drugs. It offers a large range of drug combinations with cytotoxic agents, targeted products and immuno-active biotherapeutics, to treat a variety of advanced solid carcinoma, sarcoma and cancers with progressive central nervous system diseases. A quarter of century after its first launch, IRT remains an essential anticancer drug, largely prescribed, useful to many patients and scientifically inspiring.

Preparation and Evaluation of Irinotecan Poly(Lactic-co-Glycolic Acid) Nanoparticles for Enhanced Anti-tumor Therapy

Irinotecan (IRT), the pro-drug of SN-38, has exhibited potent cytotoxicity against various tumors. In order to enhance the anti-tumor effect of IRT, we prepared IRT-loaded PLGA nanoparticles (IRT-PLGA-NPs) by emulsion-solvent evaporation method. Firstly, IRT-PLGA-NPs were characterized through drug loading (DL), entrapment efficiency (EE), particle size, zeta potential, transmission electron microscopy (TEM), and differential scanning calorimetry (DSC). We next studied the in vitro release characteristics of IRT-PLGA-NPs. Finally, the pharmacokinetics and pharmacodynamics profiles of IRT-PLGA-NPs were investigated. The results revealed that IRT-PLGA-NPs were spherical with an average size of (169.97 ± 6.29) nm and its EE and DL were (52.22 ± 2.41)% and (4.75 ± 0.22)%, respectively. IRT-PLGA-NPs could continuously release drug for 14 days in vitro. In pharmacokinetics studies, for pro-drug IRT, the t_1/2β of IRT-PLGA-NPs was extended from 0.483 to 3.327 h compared with irinotecan solution (IRT-Sol), and for its active metabolite SN-38, the t_1/2β was extended from 1.889 to 4.811 h, which indicated that IRT-PLGA-NPs could prolong the retention times of both IRT and SN-38. The pharmacodynamics results revealed that the tumor doubling time, growth inhibition rate, and specific growth rate of IRT-PLGA-NPs were 2.13-, 1.30-, and 0.47-fold those of IRT-Sol, respectively, which demonstrated that IRT-PLGA-NPs could significantly inhibit the growth of tumor. In summary, IRT-PLGA-NPs, which exhibited excellent therapeutic effect against tumors, might be used as a potential carrier for tumor treatment in clinic.

Simultaneous quantification of Gemcitabine and Irinotecan hydrochloride in rat plasma by using high performance liquid chromatography-diode array detector

In this manuscript we aimed at the simultaneous separation and quantification of Gemcitabine and Irinotecan hydrochloride (injected both as single components and in combination) from Sprague Dawley rat plasma by using a validated method obtained through the use of a High Performance Liquid Chromatography (HPLC)-diode array detector (DAD). Gemcitabine and Irinotecan hydrochloride were detected and quantified using a Zorbax Extend C-18 column (250 mm × 4.6 mm; 5 μm particle size) in gradient elution mode. The chromatographic analyses were carried out in 15 min. The analytical mode was calibrated and validated in the concentration range from 0.1 to 18 μg/mL both for Gemcitabine and Irinotecan hydrochloride. Sprague Dawley rat plasma was used to perform the analysis. 3-methylxanthine was the internal standard. The weighted-matrix matched standard curves of Gemcitabine and Irinotecan hydrochloride showed a good linearity up to 18 μg/mL. Parallelism tests were also performed to evaluate whether the over-range samples could be analyzed after dilution without affecting the analytical performance. The intra- and inter-day precision (RSD%) values of Gemcitabine and Irinotecan hydrochloride were ≤7.14% and ≤11.5%, respectively. The intra- and inter-day trueness (Bias%) values were in the range from -11.5% to 1.70% for both drugs. The analytical mode performance was further tested after collecting Sprague Dawley rat plasma following a single-dose administration of chemotherapeutics or their association. The validated HPLC-DAD method allowed the simultaneous quantification of Gemcitabine and Irinotecan hydrochloride in the rat plasma, besides the evaluation of the pharmacokinetic parameters and drug delivery.