Clinical pharmacokinetics of irinotecan

Camptothecin and its derivatives: Advancements, mechanisms and clinical potential in cancer therapy

Camptothecin (CPT), an alkaloid isolated from the Camptotheca tree, has demonstrated significant anticancer properties in a range of malignancies. However, its therapeutic efficacy is limited by its hydrophobicity, poor bioavailability, and systemic toxicity. Derivatives, analogues, and nanoformulations of CPT have been synthesized to overcome these limitations. The aim of this review is to comprehensively analyze existing studies to evaluate the therapeutic efficacy, mechanistic aspects, and clinical potential of CPT and its modified forms, including derivatives, analogues, and nanoformulations, in cancer treatment. A comprehensive literature review was performed using PubMed/Medline, Scopus, and Web of Science databases; articles were selected based on specific inclusion criteria, and data were extracted on the pharmacological profile, clinical studies, and therapeutic efficacy of CPT and its different forms. Current evidence suggests that derivatives and analogues of CPT have improved water solubility, bioavailability, and reduced systemic toxicity compared to CPT. Nanoformulations further enhance targeted delivery and reduce off-target effects. Clinical trials indicate promising outcomes with enhanced survival rates and lower side effects. CPT and its modified forms hold significant promise as potent anticancer agents. Ongoing research and clinical trials are essential for establishing their long-term efficacy and safety; the evidence overwhelmingly supports further development and clinical testing of these compounds.

Sacituzumab govitecan for hormone receptor-positive HER2-negative advanced breast cancer

INTRODUCTION

Initial treatment for hormone-receptor positive (HR+)/human epidermal growth factor receptor 2 negative (HER2-) advanced breast cancer (ABC) typically involves endocrine therapy (ET) combined with different targeted agents. When hormonal therapies fail, until recently, the only option available was chemotherapy (ChT), presenting a significant therapeutic challenge. However, the recent introduction of antibody-drug conjugates (ADCs) has provided new treatment alternatives in this context. Sacituzumab govitecan (SG), a novel trophoblast cell-surface antigen 2 (Trop-2)-targeting ADC, has been evaluated following disease progression to ET and ChT in HR+/HER2- ABC.

AREAS COVERED

This review examines the latest clinical trials, including phase I/II and III studies and evaluates the impact of SG on HR+/HER2- ABC. The literature search focused on clinical outcomes, particularly regarding efficacy and safety, comparing them with traditional ChT.

EXPERT OPINION

SG has demonstrated to be an effective treatment for patients with HR+/HER2- ABC after progression to ET and cyclin-dependent kinase 4/6 inhibitors (CDKi) in any setting, and at least two ChT-containing regimens in the advanced setting. With a manageable toxicity profile, SG represents a significant advancement in the treatment landscape for this patient population. However, further research is essential to optimize its application and establish long-term benefits.

Irinotecan hydrochloride liposome HR070803 in combination with 5-fluorouracil and leucovorin in locally advanced or metastatic pancreatic ductal adenocarcinoma following prior gemcitabine-based therapy (PAN-HEROIC-1): a phase 3 trial

Liposomal irinotecan has shown promising antitumor activity in patients with advanced or metastatic pancreatic ductal adenocarcinoma (PDAC) who have undergone prior gemcitabine-based therapies. This randomized, double-blind, parallel-controlled, multicenter phase 3 study (NCT05074589) assessed the efficacy and safety of liposomal irinotecan HR070803 combined with 5-fluorouracil (5-FU) and leucovorin (LV) in this patient population. Patients with unresectable, locally advanced, or metastatic PDAC who had previously received gemcitabine-based therapies were randomized 1:1 to receive either HR070803 (60 mg/m2 anhydrous irinotecan hydrochloride, equal to 56.5 mg/m2 free base) or placebo, both in combination with 5-FU (2000 mg/m2) and LV (200 mg/m2), all given intravenously every two weeks. The primary endpoint of the study was overall survival (OS). A total of 298 patients were enrolled and received HR070803 plus 5-FU/LV (HR070803 group, n = 149) or placebo plus 5-FU/LV (placebo group, n = 149). Median OS was significantly improved in the HR070803 group compared to the placebo group (7.4 months [95% CI 6.1-8.4] versus 5.0 months [95% CI 4.3-6.0]; HR 0.63 [95% CI 0.48-0.84]; two-sided p = 0.0019). The most common grade ≥ 3 adverse events in the HR070803 group were increased gamma-glutamyltransferase (19.0% versus 11.6% in placebo group) and decreased neutrophil count (12.9% versus 0 in placebo group). No treatment-related deaths occurred in the HR070803 group, while the placebo group reported one treatment-related death (abdominal infection). HR070803 in combination with 5-FU/LV has shown promising efficacy and manageable safety in advanced or metastatic PDAC in the second-line setting, representing a potential option in this patient population.

Fecal SN-38 Content as a Surrogate Predictor of Intestinal SN-38 Exposure and Associated Irinotecan-induced Severe Delayed-Onset Diarrhea by a Novel Use of the Spectrofluorimetric Method

BACKGROUND

Irinotecan administration can lead to severe delayed-onset diarrhea (SDOD) in clinical practice. Currently, there is no reliable surrogate predictor of intestinal exposure to SN-38 and subsequent diarrhea incidence.

METHODS

The relationship between fecal 7-ethyl-10-hydroxycamptothecin (SN-38) content and SDOD was investigated in Fisher 344 rats using a novel spectrofluorimetric method. Additionally, a pharmacokinetic study of irinotecan was performed to evaluate the biodistribution of SN-38 to establish the relationship between tissue and fecal SN-38 exposure.

RESULTS

The spectrofluorimetric method was successfully employed to measure fecal SN-38 and CPT-11 content from Day 3 to Day 6 post-irinotecan administration. Only fecal SN-38 content on Day 3 exhibited a significantly positive correlation with SDOD incidence on Days 4 and 5. A cutoff value of SN-38 ≥ 0.066 mg/g in feces was identified, predicting severe diarrhea incidence with 81% accuracy and 80% specificity. The positive correlation between fecal SN-38 content and SN-38 exposure in the ileum on Day 3 was also reflected in the changes of indicators during intestinal injury, such as prostaglandin E2 level and antioxidant activity.

CONCLUSION

Fecal SN-38 content proves to be representative of intestinal exposure to SN-38, indicative of intestinal injury, and predictive of SDOD incidence in rats, while the spectrofluorimetric method demonstrates the translational potential.

Rapid detection of the irinotecan-related UGT1A1 & 5-fluorouracil related DPYD polymorphism by asymmetric polymerase chain reaction melting curve analysis

BACKGROUND

Determination of DPYD and UGT1A1 polymorphisms prior to 5-fluorouracil and irinotecan therapy is crucial for avoiding severe adverse drug effects. Hence, there is a pressing need for accurate and reliable genotyping methods for the most common DPYD and UGT1A1 polymorphisms. In this study, we introduce a novel polymerase chain reaction (PCR) melting curve analysis method for discriminating DPYD c.1236G > A, c.1679 T > G, c.2846A > T, IVS14 + 1G > A and UGT1A1*1, *28, *6 (G71R) genotypes.

METHODS

Following protocol optimization, this technique was employed to genotype 28 patients, recruited between March 2023 and October 2023, at the First Affiliated Hospital of Xiamen University. These patients included 20 with UGT1A1 *1/*1, 8 with UGT1A1 *1/*28, 4 with UGT1A1 *28/*28, 22 with UGT1A1*6 G/G, 6 with UGT1A1*6 G/A, 4 with UGT1A1*6 A/A, 27 with DPYD(c.1236) G/G, 3 with DPYD(c.1236) G/A, 2 with DPYD(c.1236) A/A, 27 with DPYD(c.1679) T/T, 2 with DPYD(c.1679) T/G, 3 with DPYD(c.1679) G/G, 28 with DPYD(c.2846A/T) A/A, 2 with DPYD(c.2846A/T) A/T, 2 with DPYD(c.2846A/T) T/T, 28 with DPYD(c.IVS14 + 1) G/G, 2 with DPYD(c.IVS14 + 1) G/G, and 2 with DPYD(c.IVS14 + 1) G/G, as well as 3 plasmid standards. Method accuracy was assessed by comparing results with those from Sanger sequencing or Multiplex quantitative PCR(qPCR). Intra- and inter-run precision of melting temperatures (Tms) were calculated to evaluate reliability, and sensitivity was assessed through limit of detection examination.

RESULTS

The new method accurately identified all genotypes and exhibited higher accuracy than Multiplex qPCR. Intra- and inter-run coefficients of variation for Tms were both ≤1.97 %, with standard deviations ≤0.95 °C. The limit of detection was 0.09 ng/μL of input genomic DNA.

CONCLUSION

Our developed PCR melting curve analysis offers accurate, reliable, rapid, simple, and cost-effective detection of DPYD and UGT1A1 polymorphisms. Its application can be easily extended to clinical laboratories equipped with a fluorescent PCR platform.

Population pharmacokinetics of intraperitoneal irinotecan and SN-38 in patients with peritoneal metastases from colorectal origin

Peritoneal metastases (PM) are common in patients with colorectal cancer. Patients with PM have a poor prognosis, and for those who are not eligible for cytoreductive surgery (CRS) with or without hyperthermic intraperitoneal chemotherapy (HIPEC), palliative chemotherapy is currently the only option. Recently, we conducted a phase I trial (INTERACT) in which irinotecan was administered intraperitoneally (IP) to 18 patients ineligible for CRS-HIPEC. The primary objective was to evaluate covariates influencing the PK profile of irinotecan and SN-38 after IP administration. Secondly, a population PK model was developed to support the further development of IP irinotecan by improving dosing in patients with PM. Patients were treated with IP irinotecan every 2 weeks in combination with systemic FOLFOX-bevacizumab. Irinotecan and SN-38 were measured in plasma (588 samples) and SN-38 was measured in peritoneal fluid (267 samples). Concentration-Time data were log-transformed and analyzed using NONMEM version 7.5 using FOCE+I estimation. An additive error model described the residual error, with inter-individual variability in PK parameters modeled exponentially. The final structural model consisted of five compartments. Weight was identified as a covariate influencing the SN-38 plasma volume of distribution and GGT was found to influence the SN-38 plasma clearance. This population PK model adequately described the irinotecan and SN-38 in plasma after IP administration, with weight and GGT as predictive factors. Irinotecan is converted intraperitoneal to SN-38 by carboxylesterases and the plasma bioavailability of irinotecan is low. This model will be used for the further clinical development of IP irinotecan by providing dosing strategies.

Population Pharmacokinetics of Sacituzumab Govitecan in Patients with Metastatic Triple-Negative Breast Cancer and Other Solid Tumors

BACKGROUND AND OBJECTIVE

Sacituzumab govitecan (SG) is an antibody-drug conjugate composed of an antibody with affinity for Trop-2 coupled to SN-38 via hydrolyzable linker. SG is approved for patients with metastatic triple-negative breast cancer (mTNBC) who have received two or more prior chemotherapies (at least one in a metastatic setting) and for patients with pretreated hormone receptor positive (HR+)/human epidermal growth factor receptor 2 negative (HER2-) metastatic breast cancer.

METHODS

In these analyses, the pharmacokinetics of SG, free SN-38, and total antibody (tAB) were characterized using data from 529 patients with mTNBC or other solid tumors across two large clinical trials (NCT01631552; ASCENT, NCT02574455). Three population pharmacokinetic models were constructed using non-linear mixed-effects modeling; clinically relevant covariates were evaluated to assess their impact on exposure. Models for SG and tAB were developed independently whereas free SN-38 was sequentially generated via a first-order release process from SG.

RESULTS

Pharmacokinetics of the three analytes were each described by a two-compartment model with estimated body weight-based scaling exponents for clearance and volume. Typical parameter estimates for clearance and steady-state volume of distribution were 0.133 L/h and 3.68 L for SG and 0.0164 L/h and 4.26 L for tAB, respectively. Mild-to-moderate renal impairment, mild hepatic impairment, age, sex, baseline albumin level, tumor type, UGT1A1 genotype, or Trop-2 expression did not have a clinically relevant impact on exposure for any of the three analytes.

CONCLUSIONS

These analyses support the approved SG dosing regimen of 10 mg/kg as intravenous infusion on days 1 and 8 of 21-day cycles and did not identify a need for dose adjustment based on evaluated covariates or disease characteristics.

Translational Pharmacokinetic/Pharmacodynamic Modeling and Simulation of Oxaliplatin and Irinotecan in Colorectal Cancer

Despite the recent advances in this field, there are limited methods for translating organoid-based study results to clinical response. The goal of this study was to develop a pharmacokinetic/pharmacodynamic (PK/PD) model to facilitate the translation, using oxaliplatin and irinotecan treatments with colorectal cancer (CRC) as examples. The PK models were developed using qualified oxaliplatin and irinotecan PK data from the literature. The PD models were developed based on antitumor efficacy data of SN-38 and oxaliplatin evaluated in vitro using tumor organoids. To predict the clinical response, translational scaling of the models was established by incorporating predicted ultrafiltration platinum in plasma or SN-38 in tumors to PD models as the driver of efficacy. The final PK/PD model can predict PK profiles and responses following treatments with oxaliplatin or irinotecan. After generation of virtual patient cohorts, this model simulated their tumor shrinkages following treatments, which were used in analyzing the efficacies of the two treatments. Consistent with the published clinical trials, the model simulation suggested similar patient responses following the treatments of oxaliplatin and irinotecan with regards to the probabilities of progression-free survival (HR = 1.05, 95%CI [0.97;1.15]) and the objective response rate (OR = 1.15, 95%CI [1.00;1.32]). This proposed translational PK/PD modeling approach provides a significant tool for predicting clinical responses of different agents, which may help decision-making in drug development and guide clinical trial design.

Evaluation of UGT1A1 and CYP3A Genotyping and Single-Point Irinotecan and Metabolite Concentrations as Predictors of the Occurrence of Adverse Events in Cancer Treatment

PURPOSE

The variability on irinotecan (IRI) pharmacokinetics and toxicity has been attributed mostly to genetic variations in the UGT1A1 gene, responsible for conjugation of the active metabolite SN-38. Also, CYP3A mediates the formation of inactive oxidative metabolites of IRI. The association between the occurrence of severe adverse events, pharmacokinetics parameters, and UGT1A1 and CYP3A4 predicted phenotypes was evaluated, as the evaluation of [SN-38]/IRI dose ratio as predictor of severe adverse events.

METHODS

Forty-one patients undergoing IRI therapy were enrolled in the study. Blood samples were collected 15 min after the end of drug the infusion, for IRI, SN-38, SN-38G, bilirubin concentrations measurements, and UGT1A1 and CYP3A genotype estimation. Data on adverse event was reported.

RESULTS

Fifteen patients (36.5%) developed grade 3/4 adverse events. A total of 9.8% (n = 4) of the patients had UGT1A1 reduced activity phenotype, and 48.7% (n = 20) had UGT1A1 and 63.4% (n = 26) CYP3A intermediary phenotypes. Severe neutropenia and diarrhea were more prevalent in patients with reduced UGT1A1 in comparison with functional metabolism (50% and 75% versus 0% and 13%, respectively). SN-38 levels and its concentrations adjusted by IRI dose were significantly correlated to toxicity (rs = 0.31 (p = 0.05) and rs = 0.425 (p < 0.01)). The [SN-38]/IRI dose ratio had a ROC curve of 0.823 (95% CI 0.69-0.956) to detect any severe adverse event and 0.833 (95% CI 0.694-0.973) to detect severe diarrhea. The cut-off of 0.075 ng mL-1 mg-1 had 100% sensitivity and 65.7% specificity to predict severe diarrhea.

CONCLUSION

Our data confirmed the relevance of the pre-emptive genotypic information of UGT1A1. The [SN-38]/IRI ratio, measured 15 min after the end of the IRI infusion, was a strong predictor of severe toxicity and could be applied to minimize the burden of patients after IRI administration.

Transporter and metabolic enzyme-mediated intra-enteric circulation of SN-38, an active metabolite of irinotecan: A new concept

SN-38, an active metabolite of irinotecan (CPT-11), is thought to circulate enterohepatically via organic anion-transporting polypeptides (OATPs), UDP-glucuronyl transferases (UGTs), multidrug resistance-related protein 2 (MRP2), and breast cancer resistance protein (BCRP). These transporters and enzymes are expressed in not only hepatocytes but also enterocytes. Therefore, we hypothesized that SN-38 circulates between the intestinal lumen and the enterocytes via these transporters and metabolic enzymes. To test this hypothesis, metabolic and transport studies of SN-38 and its glucuronide (SN-38G) were conducted in Caco-2 cells. The mRNA levels of UGTs, MRP2, BCRP, and OATP2B1 were confirmed in Caco-2 cells. SN-38 was converted to SN-38G in Caco-2 cells. The efflux of intracellularly generated SN-38G across the apical (digestive tract) membranes was significantly higher than the efflux across the basolateral (blood, portal vein) membranes of Caco-2 cells cultured on polycarbonate membranes. SN-38G efflux to the apical side was significantly reduced in the presence of MRP2 and BCRP inhibitors, suggesting that SN-38G is transported across the apical membrane by MRP2 and BCRP. Treatment of Caco-2 cells with OATP2B1 siRNA increased the SN-38 residue on the apical side, confirming that OATP2B1 is involved in the uptake of SN-38 into enterocytes. No SN-38 was detected on the basolateral side with or without siRNA treatment, suggesting that the enterohepatic circulation of SN-38 is limited, contrary to previous reports. These results suggest that SN-38 is absorbed into the enterocytes via OATP2B1, glucuronidated by UGTs to SN-38G, and excreted into the digestive tract lumen by MRP2 and BCRP. SN-38G can be deconjugated by β-glucuronidase from intestinal bacteria in the digestive tract lumen to regenerate SN-38. We named this new concept of local drug circulation "intra-enteric circulation." This mechanism may allow SN-38 to circulate in the intestine and cause the development of delayed diarrhea, a serious side effect of CPT-11.

Novel disulfide bond bridged 7-ethyl-10-hydroxyl camptothecin-undecanoic acid conjugate/human serum albumin nanoparticles for breast cancer therapy

7-Ethyl-10-hydroxyl camptothecin (SN38), a semisynthetic derivative of camptothecin, exhibited extreme pharmacological activities in treating a range of cancers. However, its poor aqueous solubility and low stability hinder its clinical applications. Hence, a redox-responsive SN38 prodrug encapsulated human serum albumin (HSA) nanoparticle is developed to realize its potential in the clinic. First, a disulfide bond bridged 7-ethyl-10-hydroxyl camptothecin-undecanoic acid conjugate (SN38-SS-COOH) was synthesized and characterized structurally. After that, SN38-SS-COOH/HSA nanoparticles (SNH NPs) were prepared by the desolvation method. The SNH NPs with a feed molar ratio of 9 : 1 of SN38-SS-COOH : HSA showed a spherical structure with a diameter range of approximately 120-150 nm revealed by dynamic light scattering (DLS) and transmission electron microscopy (TEM). Fluorescence quenching confirmed the formation of SNH NP complexes by dual hydrophobic force and electrostatic interaction. The SNH NPs have a high drug loading of 10.44% and an encapsulation efficiency of 89.59% with good stability. Moreover, the redox responsiveness was validated by glutathione (GSH)-triggered accelerated release of parent drug SN38. In an in vivo pharmacokinetic study, the SNH NPs exhibited a significantly prolonged circulation time (t_1/2, 3.77-fold) compared with free SN38. Finally, the in vivo antitumor efficacy and systemic toxicity of SNH NPs in a breast xenograft model were thoroughly evaluated. The inhibition rate of tumor growth induced by the SNH NPs reached 70.1%, while only 50.1% was achieved for irinotecan at an equivalent SN38 dosage of 10 mg kg^-1. More importantly, the SNH NPs achieved a higher level of tumor growth inhibition (85.3%) by increasing the dosage to 60 mg kg^-1 SN38 without obvious adverse effects. Taken together, the use of redox-responsive SN38 prodrug/HSA NPs could be a promising strategy to deliver highly active SN38 for breast cancer chemotherapy.

Reactive oxygen species as mediators of disease progression and therapeutic response in colorectal cancer

Significance Reactive oxygen species (ROS) are critical to normal cellular function with redox homeostasis achieved by balancing ROS production with removal through detoxification mechanisms. Many of the conventional chemotherapies used to treat colorectal cancer (CRC) derive a proportion of their cytotoxicity from ROS generation and resistance to chemotherapy is associated with elevated detoxification mechanisms. Furthermore, cancer stem cells demonstrate elevated detoxification mechanisms making definitive treatment with existing chemotherapy challenging. In this article we review the roles of ROS in normal and malignant colonic cell biology and how existing and emerging therapies might harness ROS for therapeutic benefit. Recent advances Recent publications have elucidated the contribution of ROS to the cytotoxicity of conventional chemotherapy alongside the emerging approaches of photodynamic therapy (PDT), sonodynamic therapy (SDT) and radiodynamic therapy (RDT) in which ROS are generated in response to excitatory light, sound or X-ray stimuli to promote cancer cell apoptosis. Critical issues The majority of patients with metastatic CRC have a very poor prognosis with 5-year survival of approximately 13% making the need for new or more effective treatments an imperative. Future Directions Modulation of ROS through a combination of new and emerging therapies may improve the efficacy of current chemotherapy providing novel approaches to treat otherwise resistant disease.

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.

HROP68: A rare case of medullary pancreatic cancer-characterization and chemosensitivity of the first patient-derived cell line

Introduction

Medullary pancreatic carcinoma (MPC) is a rare subtype of pancreatic ductal adenocarcinoma. MPCs represent less than 1% of all pancreatic cancers, and, with only 26 cases in the literature, knowledge regarding drug response and treatment outcome is very limited.

Material and methods

We present the case of a 64-year-old male patient with MPC who was treated by left pancreatic resection and adjuvant chemotherapy. Due to local recurrence, the patient underwent intended curative reoperation. From both surgical specimens, patient-derived xenografts (PDXs) and, from the recurrence, a patient-derived cell line (PDCL) were established. We subsequently performed an in-depth characterization of this cell line including phenotypic characterization, surface protein expression, growth, and migratory performance as well as mutational analysis using whole-exome sequencing (WES). Additionally, in vitro drug sensitivity toward the standard-of-care chemotherapeutic regimen and selected targeted therapies was evaluated.

Results

The pathological and molecular properties of this rare MPC case observed in the patient's tumors are preserved in the corresponding PDX and the PDCL of HROP68Tu2. Despite displaying an "immunogenic phenotype" with marked T-cell infiltration and a high-level expression of HLA II and Programmed death-ligand 1 (PD-L1), molecular analysis revealed microsatellite stability but a multitude of mutations affecting KRAS, TP53, KAT6B, FOXG1, RUNX1, and GRIK2 among others. Furthermore, HROP68Tu2 cells were susceptible toward 5-FU, irinotecan, oxaliplatin, gemcitabine, paclitaxel, and erlotinib as single agents, but only a moderate synergistic response was seen to the drugs of the FOLFIRINOX regimen. Even worse, the drugs of the two combinations gemcitabine plus paclitaxel and gemcitabine plus erlotinib showed antagonistic effects. Moreover, lapatinib, PRIMA-Met1, and olaparib selected as targeted therapeutics according to the mutational profiles and protein expression inhibited HROP68Tu2 cells' growth.

Conclusion

This study illustrates the establishment of the first preclinical MPC models as well as the first in-depth characterization of an MPC PDCL. Since the scientific and clinical knowledge of this rare pancreatic cancer type is very limited, the presented models contribute to a better understanding of MPC and might be a valuable tool for the development of future treatment options.

Population pharmacokinetic analysis of TQ-B3203 following intravenous administration of TQ-B3203 liposome injection in Chinese patients with advanced solid tumors

Background: TQ-B3203 is a novel topoisomerase I inhibitor currently in development for the treatment of advanced solid tumors. Great differences in pharmacokinetic characteristics were found among individuals according to the phase I clinical trial following intravenous administration of TQ-B3203 liposome injection (TLI) in Chinese patients with advanced solid tumors. Thus, it is significant to establish a population pharmacokinetic model to find the key factors and recognize their effect on pharmacokinetic parameters in order to guide individualized administration. Methods: Non-linear mixed effect models were developed using the plasma concentrations obtained from the phase I clinical trial by implementing the Phoenix NLME program. Covariates that may be related to pharmacokinetics were screened using stepwise methods. The final model was validated by goodness-of-fit plots, visual predictive check, non-parametric bootstrap and a test of normalized prediction distribution errors. Results: A three-compartment model with first-order elimination was selected as the best structural model to describe TQ-B3203 disposition adequately. Direct bilirubin (DBIL) and body mass index (BMI) were the two most influential factors on clearance, while lean body weight (LBW) was considered to affect the apparent distribution volume of the central compartment. The population estimations of clearance and central volume were typical at 3.97 L/h and 4.81 L, respectively. Model-based simulations indicated that LBW had a great impact on C_max, BMI exerted a considerable influence on AUC_0-t, and the significance of DBIL on both AUC_0-t and C_max was similarly excellent. Conclusion: The first robust population pharmacokinetic model of TQ-B3203 was successfully generated following intravenous administration of TLI in Chinese patients with advanced solid tumors. BMI, LBW and DBIL were significant covariates that affected the pharmacokinetics of TQ-B3203. This model could provide references for the dose regimen in the future study of TLI.

Spatial Alignment of Organoids Tracking Subclonal Chemotherapy Resistance in Pancreatic and Ampullary Cancer

Pancreatic and ampullary cancers remain highly morbid diseases for which accurate clinical predictions are needed for precise therapeutic predictions. Patient-derived cancer organoids have been widely adopted; however, prior work has focused on well-level therapeutic sensitivity. To characterize individual oligoclonal units of therapeutic response, we introduce a low-volume screening assay, including an automated alignment algorithm. The oligoclonal growth response was compared against validated markers of response, including well-level viability and markers of single-cell viability. Line-specific sensitivities were compared with clinical outcomes. Automated alignment algorithms were generated to match organoids across time using coordinates across a single projection of Z-stacked images. After screening for baseline size (50 μm) and circularity (>0.4), the match efficiency was found to be optimized by accepting the diffusion thresholded with the root mean standard deviation of 75 μm. Validated well-level viability showed a limited correlation with the mean organoid size (R = 0.408), and a normalized growth assayed by normalized changes in area (R = 0.474) and area (R = 0.486). Subclonal populations were defined by both residual growth and the failure to induce apoptosis and necrosis. For a culture with clinical resistance to gemcitabine and nab-paclitaxel, while a therapeutic challenge induced a robust effect in inhibiting cell growth (GΔ = 1.53), residual oligoclonal populations were able to limit the effect on the ability to induce apoptosis (GΔ = 0.52) and cell necrosis (GΔ = 1.07). Bioengineered approaches are feasible to capture oligoclonal heterogeneity in organotypic cultures, integrating ongoing efforts for utilizing organoids across cancer types as integral biomarkers and in novel therapeutic development.

NEDDylated Cullin 3 mediates the adaptive response to topoisomerase 1 inhibitors

DNA topoisomerase 1 (TOP11) inhibitors are mainstays of anticancer therapy. These drugs trap TOP1 on DNA, stabilizing the TOP1-cleavage complex (TOP1-cc). The accumulation of TOP1-ccs perturbs DNA replication fork progression, leading to DNA breaks and cell death. By analyzing the genomic occupancy and activity of TOP1, we show that cells adapt to treatment with multiple doses of TOP1 inhibitor by promoting the degradation of TOP1-ccs, allowing cells to better tolerate subsequent doses of TOP1 inhibitor. The E3-RING Cullin 3 ligase in complex with the BTBD1 and BTBD2 adaptor proteins promotes TOP1-cc ubiquitination and subsequent proteasomal degradation. NEDDylation of Cullin 3 activates this pathway, and inhibition of protein NEDDylation or depletion of Cullin 3 sensitizes cancer cells to TOP1 inhibitors. Collectively, our data uncover a previously unidentified NEDD8-Cullin 3 pathway involved in the adaptive response to TOP1 inhibitors, which can be targeted to improve the efficacy of TOP1 drugs in cancer therapy.

Pulmonary delivery of liposomes co-loaded with SN38 prodrug and curcumin for the treatment of lung cancer

A co-delivery system of SN38 (7-ethyl-10-hydroxyl camptothecin) prodrug and CUR (curcumin) was designed for the treatment of lung cancer by pulmonary delivery. SN38 was linked to cell-penetrating peptide (CPP) TAT via a polyethylene glycol (PEG) linker to form the SN38 prodrug (TAT-PEG-SN38). Liposomes co-loaded with amphiphilic TAT-PEG-SN38 and curcumin (Lip-TAT-PEG-SN38/CUR) were successfully prepared by a microfluidic method for the treatment of lung cancer via pulmonary delivery. Lip-TAT-PEG-SN38/CUR showed nanometer-sized sphericity and a particle size of 171.21 nm. Besides, Lip-TAT-PEG-SN38/CUR exhibited enhanced antiproliferative effect, increased cell apoptosis induction and improved cell cycle arrest compared to the single agents in vitro. The combination induced significant tumor inhibition in a BALB/c mouse lung cancer model. These results indicated that our SN38 prodrug and curcumin co-delivery system was a promising candidate for lung cancer treatment.

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.

Orally delivered solid lipid nanoparticles of irinotecan coupled with chitosan surface modification to treat colon cancer: Preparation, in-vitro and in-vivo evaluations

Irinotecan-loaded solid lipid nanoparticles (IRI-SLNs) was formulated and tested for its potential activity against colon cancer. IRI-SLNs were prepared by applying the principles of DoE. Nanoparticles were further surface modified using chitosan. Characterizations such as size, poly-dispersity, surface charge, morphology, entrapment, drug release pattern, cytotoxicity were conducted. In-vivo studies in male Wistar rats were carried to ascertain distribution pattern of SLNs and their acute toxicity on various vital organs. Lastly, stability of the SLNs were evaluated. Particles had a size, polydispersity and zeta potential of 430.77 ± 8.69 nm, 0.36 ± 0.02 and -40.06 ± 0.61 mV, respectively. Entrapment of IRI was 62.24 ± 2.90% in IRI-SLNs. Sustained drug release was achieved at a colonic pH and long-term stability of NPs was seen. Cytotoxicity assay results showed that SLNs exhibited toxicity on HCT-116 cells. Biodistribution studies confirmed higher concentration of drug in the colon after surface modification. An acute toxicity study conducted for 7 days showed no severe toxic effects on major organs. Thus, we picture that the developed SLNs may benefit in delivering IRI to the tumour cells, therefore decreasing the dose and dose-associated toxicities.

Impact of low- and high-risk operators handling irinotecan on the blood contamination of health care workers in oncology day care units

INTRODUCTION

Health care workers handling antineoplastic drugs (ADs) are at risk of mutagenicity and adverse reproductive effects. Despite protective equipment and AD handling guidelines, AD levels are still detected in caregivers in oncology units. This study attempted to assess blood contamination by irinotecan and its metabolites in all health care workers in oncology day hospital units according to activities specific to each employment category.

METHODS

The study was performed at two different hospitals: a university hospital and a comprehensive cancer centre. Forty-four participants were categorized according to their daily activity as a high-risk operator (29 nurses/ward aides and 5 cleaning staff) and a low-risk operator (7 doctors and 3 secretaries). The collected blood samples were subjected to UHPLC-MS/MS. The plasma and red blood cell (RBC) levels of irinotecan and its metabolites (SN-38; APC) were determined using a validated analytical method detection test.

RESULTS

Two hundred sixty-four assay results were collected (132 plasma results and 132 RBC results). The comparison between low- and high-risk operator-contaminated workers was not significant (18.33% positive results in low-risk operators vs. 25.98% positive results in high-risk operators; P = 0.22). This homogeneity showed overall contamination within the unit. Positive results were obtained in 21.43% of physicians, 11.11% of secretaries, 25.86% of nurses/ward aides and 26.67% of cleaning staff. These results could be explained by the lack or failure of personal and collective protective equipment. A lack of protection and inadequate decontamination procedures can result in surface contamination.

CONCLUSIONS

This study evaluated blood contamination with irinotecan and its metabolites in health care workers from day hospital care units. Among the 24.24% of contaminations observed in care units, the difference between low- and high-risk operator contamination was not significant (P = 0.22). The impact on blood contamination found is the same between low- and high-risk caregivers. This implies that the protective precautions associated with the handling of anticancer drugs must therefore be followed by all staff, including those believed to be at low risk of exposure.

Exposure to Antineoplastic Drugs in Occupational Settings: A Systematic Review of Biological Monitoring Data

The high toxicity of antineoplastic drugs (ADs) makes them dangerous not only for patients, but also for exposed workers. Therefore, the aim of this review was to provide an updated overview of the biological monitoring of occupational AD exposure in order to extrapolate information useful to improve risk assessment and management strategies in workplaces. Several studies demonstrated that remarkable portions of healthcare workers may have traces of these substances or their metabolites in biological fluids, although with some conflicting results. Nurses, directly engaged in AD handling, were the occupational category at higher risk of contamination, although, in some cases, personnel not involved in AD-related tasks also showed quantifiable internal doses. Overall, further research carried out on greater sample sizes appears necessary to gain deeper insight into the variability retrieved in the reported results. This may be important to understand the impact of the extent of ADs use, different handling, procedures, and cleaning practices, spill occurrence, training of the workforce, as well as the adoption of adequate collective and personal protective equipment in affecting the occupational exposure levels. This may support the achievement of the greatest clinical efficiency of such therapies while assuring the health and safety of involved workers.

Inhibition of the HIF-1 Survival Pathway as a Strategy to Augment Photodynamic Therapy Efficacy

Photodynamic therapy (PDT) is a non-to-minimally invasive treatment modality that utilizes photoactivatable drugs called photosensitizers to disrupt tumors with locally photoproduced reactive oxygen species (ROS). Photosensitizer activation by light results in hyperoxidative stress and subsequent tumor cell death, vascular shutdown and hypoxia, and an antitumor immune response. However, sublethally afflicted tumor cells initiate several survival mechanisms that account for decreased PDT efficacy. The hypoxia inducible factor 1 (HIF-1) pathway is one of the most effective cell survival pathways that contributes to cell recovery from PDT-induced damage. Several hundred target genes of the HIF-1 heterodimeric complex collectively mediate processes that are involved in tumor cell survival directly and indirectly (e.g., vascularization, glucose metabolism, proliferation, and metastasis). The broad spectrum of biological ramifications culminating from the activation of HIF-1 target genes reflects the importance of HIF-1 in the context of therapeutic recalcitrance. This chapter elaborates on the involvement of HIF-1 in cancer biology, the hypoxic response mechanisms, and the role of HIF-1 in PDT. An overview of inhibitors that either directly or indirectly impede HIF-1-mediated survival signaling is provided. The inhibitors may be used as pharmacological adjuvants in combination with PDT to augment therapeutic efficacy.

Tumour-Derived Cell Lines and Their Potential for Therapy Prediction in Patients with Metastatic Colorectal Cancer

The prognosis of metastatic colorectal cancer (CRC) remains poor. Patients and physicians are in need of individual therapies and precise response predictions. We investigated the predictive capacity of primary tumour material for treatment response of metastases. Mutational landscapes of primary tumours and corresponding metastases of 10 CRC patients were compared. Cell line characteristics and chemosensitivity were investigated pairwise for primary and metastatic tumours of four patients. PDX models of one patient were treated in vivo for proof of concept. Driver mutations did not differ between primaries and metastases, while the latter accumulated additional mutations. In vitro chemosensitivity testing revealed no differences for responses to 5-FU and oxaliplatin between primary and metastatic cell lines. However, irinotecan response differed significantly: the majority of metastases-derived cell lines was less sensitive to irinotecan than their matching primary counterpart. Therapy recommendations based on these findings were compared to clinical treatment response and mostly in line with the predicted outcome. Therefore, primary tumour cell models seem to be a good tool for drug response testing and conclusion drawing for later metastases. With further data from tumour-derived cell models, such predictions could improve clinical treatment decisions, both recommending likely effective therapeutic options while excluding ineffective treatments.

Adverse Effects and Safety of Etirinotecan Pegol, a Novel Topoisomerase Inhibitor, in Cancer Treatment: A Systematic Review

Background:

Due to the increasing prevalence of cancer and the inadequacy of current therapies, the development of novel antitumor pharmaceutics with higher efficacies and lower adverse effects is considered a fundamental tenet of contemporary cancer management. Poly-Ethylene-Glycol (PEG) attachment is a novel pharmaceutical technology to improve the efficacy and safety of chemotherapies. Etirinotecan Pegol (EP), also known as NKTR-102, is the PEGylated form of Irinotecan (CPT-11), which causes cancer cell apoptosis by inhibiting the topoisomerase I enzyme.

Objectives:

The present study reviews and evaluates various reports of the EP’s anti-tumor activity in various cancers.

Data Sources:

Studies were identified using the Scopus database, with no exclusions. The search terms included Etirinotecan Pegol and NKTR-102, which yielded 125 articles (66 and 59 articles, respectively). In addition, the clinicaltrials.gov website was used to find ongoing studies, which resulted in the addition of two studies.

Study Eligibility Criteria:

Subsequently, we excluded studies that were published in languages other than English, duplicate articles, and studies with no data.

Results:

This systematic review clarifies that EP possesses numerous advantages over many other medications, such as safety, efficacy, increased half-life, increased health-related quality of life, increased overall survival, increased progression-free survival, and decreasing the adverse events in the treatment of various cancers.

Conclusion:

Therefore, Etirinotecan Pegol may represent a major contribution to the treatment of various cancers in the future.

Predicting potential small molecule-miRNA associations based on bounded nuclear norm regularization

Mounting evidence has demonstrated the significance of taking microRNAs (miRNAs) as the target of small molecule (SM) drugs for disease treatment. Given the fact that exploring new SM-miRNA associations through biological experiments is extremely expensive, several computing models have been constructed to reveal the possible SM-miRNA associations. Here, we built a computing model of Bounded Nuclear Norm Regularization for SM-miRNA Associations prediction (BNNRSMMA). Specifically, we first constructed a heterogeneous SM-miRNA network utilizing miRNA similarity, SM similarity, confirmed SM-miRNA associations and defined a matrix to represent the heterogeneous network. Then, we constructed a model to complete this matrix by minimizing its nuclear norm. The Alternating Direction Method of Multipliers was adopted to minimize the nuclear norm and obtain predicted scores. The main innovation lies in two aspects. During completion, we limited all elements of the matrix within the interval of (0,1) to make sure they have practical significance. Besides, instead of strictly fitting all known elements, a regularization term was incorporated to tolerate the noise in integrated similarities. Furthermore, four kinds of cross-validations on two datasets and two types of case studies were performed to evaluate the predictive performance of BNNRSMMA. Finally, BNNRSMMA attained areas under the curve of 0.9822 (0.8433), 0.9793 (0.8852), 0.8253 (0.7350) and 0.9758 ± 0.0029 (0.8759 ± 0.0041) under global leave-one-out cross-validation (LOOCV), miRNA-fixed LOOCV, SM-fixed LOOCV and 5-fold cross-validation based on Dataset 1(Dataset 2), respectively. With regard to case studies, plenty of predicted associations have been verified by experimental literatures. All these results confirmed that BNNRSMMA is a reliable tool for inferring associations.

Establishment of Pancreatobiliary Cancer Zebrafish Avatars for Chemotherapy Screening

Background: Cancers of the pancreas and biliary tree remain one of the most aggressive oncological malignancies, with most patients relying on systemic chemotherapy. However, effective biomarkers to predict the best therapy option for each patient are still lacking. In this context, an assay able to evaluate individual responses prior to treatment would be of great value for clinical decisions. Here we aimed to develop such a model using zebrafish xenografts to directly challenge pancreatic cancer cells to the available chemotherapies. Methods: Zebrafish xenografts were generated from a Panc-1 cell line to optimize the pancreatic setting. Pancreatic surgical resected samples, without in vitro expansion, were used to establish zebrafish patient-derived xenografts (zAvatars). Upon chemotherapy exposure, zAvatars were analyzed by single-cell confocal microscopy. Results: We show that Panc-1 zebrafish xenografts are able to reveal tumor responses to both FOLFIRINOX and gemcitabine plus nanoparticle albumin-bound (nab)-paclitaxel in just 4 days. Moreover, we established pancreatic and ampullary zAvatars with patient-derived tumors representative of different histological types. Conclusion: Altogether, we provide a short report showing the feasibility of generating and analyzing with single-cell resolution zAvatars from pancreatic and ampullary cancers, with potential use for future preclinical studies and personalized treatment.

Alleviation of Abdominal Pain due to Irinotecan-Induced Cholinergic Syndrome Using Loperamide: A Case Report

Irinotecan hydrochloride (irinotecan) is a chemotherapeutic agent used in the treatment of solid tumors. In addition to severe neutropenia and delayed diarrhea, irinotecan causes cholinergic syndrome, characterized by abdominal pain and acute diarrhea. The latter symptoms are frequently observed during and after irinotecan treatment. Here, we have discussed the case of a patient who completely recovered from abdominal pain following the administration of loperamide hydrochloride (loperamide) at a dose of 2 mg, before infusing irinotecan. In contrast, anticholinergic drugs were not as effective in alleviating symptoms. A 28-year-old man with stage IV rectal cancer with peritoneal metastasis was prescribed with fluorouracil, irinotecan, and levofolinate calcium (FOLFIRI), in addition to cetuximab. Anticholinergic drugs, such as scopolamine butylbromide (scopolamine) or atropine sulfate (atropine), were administered to treat abdominal pain that was considered as irinotecan-induced cholinergic syndrome, but monotherapy was not effective. Thereafter, oral loperamide (2 mg) with atropine (0.25 mg) was prescribed before irinotecan infusion. Consequently, the patient did not experience any abdominal pain during and after irinotecan treatment. Loperamide is an opioid receptor agonist and decreases the activity of the myenteric plexus of the intestinal wall. It also inhibits the release of both acetylcholine and prostaglandins, resulting in decreased inhibition of peristaltic movement. We assumed that its mechanism solely or in combination contributed to symptom relief. We hypothesized that the synergistic anticholinergic interaction between loperamide and atropine resulted in marked suppression of irinotecan-induced cholinergic syndrome compared to loperamide alone. Thus, loperamide may improve abdominal pain attributed to irinotecan-induced cholinergic syndrome.

Irinotecan (CPT-11) Canonical Anti-Cancer Drug Can also Modulate Antiviral and Pro-Inflammatory Responses of Primary Human Synovial Fibroblasts

Alphaviruses are a group of arboviruses that generate chronic inflammatory rheumatisms in humans. Currently, no approved vaccines or antiviral therapies are available to prevent or treat alphavirus-induced diseases. The aim of this study was to evaluate the repositioning of the anti-cancer molecule irinotecan as a potential modulator of the antiviral and inflammatory responses of primary human synovial fibroblasts (HSF), the main stromal cells of the joint synovium. HSF were exposed to O’nyong-nyong virus (ONNV) and polyinosinic-polycytidylic acid (PIC) to mimic, respectively, acute and chronic infectious settings. The cytokine IL-1β was used as a major pro-inflammatory cytokine to stimulate HSF. Quantitative RT-PCR analysis revealed that irinotecan at 15 µM was able to amplify the antiviral response (i.e., interferon-stimulated gene expression) of HSF exposed to PIC and reduce the expression of pro-inflammatory genes (CXCL8, IL-6 and COX-2) upon IL-1β treatment. These results were associated with the regulation of the expression of several genes, including those encoding for STAT1, STAT2, p53 and NF-κB. Irinotecan did not modulate these responses in both untreated cells and cells stimulated with ONNV. This suggests that this drug could be therapeutically useful for the treatment of chronic and severe (rather than acute) arthritis due to viruses.

Pharmacogenomics and functional imaging to predict irinotecan pharmacokinetics and pharmacodynamics: the predict IR study

PURPOSE

Irinotecan (IR) displays significant PK/PD variability. This study evaluated functional hepatic imaging (HNI) and extensive pharmacogenomics (PGs) to explore associations with IR PK and PD (toxicity and response).

METHODS

Eligible patients (pts) suitable for Irinotecan-based therapy. At baseline: (i) PGs: blood analyzed by the Affymetrix-DMET™-Plus-Array (1936 variants: 1931 single nucleotide polymorphisms [SNPs] and 5 copy number variants in 225 genes, including 47 phase I, 80 phase II enzymes, and membrane transporters) and Sanger sequencing (variants in HNF1A, Topo-1, XRCC1, PARP1, TDP, CDC45L, NKFB1, and MTHFR), (ii) HNI: pts given IV 250 MBq-^99mTc-IDA, data derived for hepatic extraction/excretion parameters (CL_HNI, T_1/2-HNI, 1hRET, HEF, T_d1/2). In cycle 1, blood was taken for IR analysis and PK parameters were derived by non-compartmental methods. Associations were evaluated between HNI and PGs, with IR PK, toxicity, objective response rate (ORR) and progression-free survival (PFS).

RESULTS

N = 31 pts. The two most significant associations between PK and PD with gene variants or HNI parameters (P < 0.05) included: (1) PK: SN38-Metabolic Ratio with CL_HNI, 1hRET, (2) Grade 3+ diarrhea with SLC22A2 (rs 316019), GSTM5 (rs 1296954), (3) Grade 3+ neutropenia with CL_HNI, 1hRET, SLC22A2 (rs 316019), CYP4F2 (rs2074900) (4) ORR with ALDH2 (rs 886205), MTHFR (rs 1801133). (5) PFS with T_1/2-HNI, XDH (rs 207440), and ABCB11 (rs 4148777).

CONCLUSIONS

Exploratory associations were observed between Irinotecan PK/PD with hepatic functional imaging and extensive pharmacogenomics. Further work is required to confirm and validate these findings in a larger cohort of patients.

AUSTRALIAN NEW ZEALAND CLINICAL TRIALS REGISTRY (ANZCTR) NUMBER

ACTRN12610000897066, Date registered: 21/10/2010.

Optimum multi-drug regime for compartment model of tumour: cell-cycle-specific dynamics in the presence of resistance

This work is focused on multi-objective optimisation of a multi-drug chemotherapy schedule for cell-cycle-specific cancer treatment under the influence of drug resistance. The acquired drug resistance to chemotherapeutic agents is incorporated into the existing compartmental model of breast cancer. Furthermore, the toxic effect of drugs on healthy cells and overall drug concentration in the patient body are also constrained in the proposed model. The objective is to determine the optimal drug schedule according to the patient's physiological condition so that the tumour burden is minimised. A multi-objective optimisation algorithm, non-dominated sorting genetic algorithm-II (NSGA-II) is utilised to solve the problem. The obtained results are thoroughly analysed to illustrate the impact of drug resistance on the treatment. The capability of optimised schedules to deal with parametric uncertainty is also analysed. The drug schedules obtained in this work align well with the clinical standards. It is also revealed that the NSGA-II optimised drug schedule with proper rest period between successive dosages yields the minimum cancer load at the end of the treatment.

"Sweet tooth"-oriented SN38 prodrug delivery nanoplatform for targeted gastric cancer therapy

Most cancer cells employ overexpression of glucose transports (GLUTs) to satisfy glucose demand ("Sweet Tooth") for increased aerobic glycolysis rates. GLUT1, one of the most widely expressed GLUTs in numerous cancers, was identified as a prognosis-related biomarker of gastric cancer via tissue array analysis. Herein, a "Sweet Tooth"-oriented SN38 prodrug delivery nanoplatform (Glu-SNP) was developed for targeted gastric cancer therapy. For this purpose, a SN38-derived prodrug (PLA-SN38) was synthesized by tethering 7-ethyl-10-hydroxycamptothecin (SN38) to biocompatible polylactic acid (PLA) with the appropriate degree of polymerization (n = 44). The PLA-SN38 conjugate was further assembled with glycosylated amphiphilic lipid to obtain glucosamine-decorated nanoparticles (Glu-SNP). Glu-SNP exhibited potent antitumor efficiency both in vitro and in vivo through enhanced cancer cell-specific targeting associated with the overexpression of GLUT1, which provides a promising approach for gastric cancer therapy.

The O6-methyguanine-DNA methyltransferase inhibitor O6-benzylguanine enhanced activity of temozolomide + irinotecan against models of high-risk neuroblastoma

DNA-damaging chemotherapy is a major component of therapy for high-risk neuroblastoma, and patients often relapse with treatment-refractory disease. We hypothesized that DNA repair genes with increased expression in alkylating agent resistant models would provide therapeutic targets for enhancing chemotherapy. In-vitro cytotoxicity of alkylating agents for 12 patient-derived neuroblastoma cell lines was assayed using DIMSCAN, and mRNA expression of 57 DNA repair, three transporter, and two glutathione synthesis genes was assessed by TaqMan low-density array (TLDA) with further validation by qRT-PCR in 26 cell lines. O6-methylguanine-DNA methyltransferase (MGMT) mRNA was upregulated in cell lines with greater melphalan and temozolomide (TMZ) resistance. MGMT expression also correlated significantly with resistance to TMZ+irinotecan (IRN) (in-vitro as the SN38 active metabolite). Forced overexpression of MGMT (lentiviral transduction) in MGMT non-expressing cell lines significantly increased TMZ+SN38 resistance. The MGMT inhibitor O6-benzylguanine (O6BG) enhanced TMZ+SN38 in-vitro cytotoxicity, H2AX phosphorylation, caspase-3 cleavage, and apoptosis by terminal deoxynucleotidyl transferase dUTP nick end labeling. TMZ+IRN+O6BG delayed tumor growth and increased survival relative to TMZ+IRN in two of seven patient-derived xenografts established at time of death from progressive neuroblastoma. We demonstrated that high MGMT expression was associated with resistance to alkylating agents and TMZ+IRN in preclinical neuroblastoma models. The MGMT inhibitor O6BG enhanced the anticancer effect of TMZ+IRN in vitro and in vivo. These results support further preclinical studies exploring MGMT as a therapeutic target and biomarker of TMZ+IRN resistance in high-risk neuroblastoma.

Tuning the efficacy of esterase-activatable prodrug nanoparticles for the treatment of colorectal malignancies

Colorectal cancer (CRC) is one of the most common and lethal human cancers, and the clinical outcomes remain unsatisfactory because of the lack of effective and safe therapeutic regimens. Here, we describe a practical and potent delivery approach for the human topoisomerase I inhibitor 7-ethyl-10-hydroxycamptothecin (SN38) against CRC. Injectable SN38-loaded nanoparticles are obtained through covalent ligation of the SN38 agent with oligo-ε-caprolactone (oligoCL) to form oligoCL-SN38 conjugates via an esterase-activatable linkage followed by encapsulation of these prodrugs in exogenous polymer matrices. Prodrug nanoparticles with adaptive features are sufficiently stable during blood circulation, while active drugs can be released in response to intracellular esterase. The administration of nanoparticle drugs results in durable tumor recession, and the efficacy is superior to that of the current standard-of-care therapy, CPT-11, in multiple mouse models of CRC, one of which is a chemically induced orthotopic CRC. Elucidation of the mechanism underlying these differing efficacies shows that nanoparticle delivery produces a substantial increase in the intratumoral concentration of the therapeutic agent relative to CPT-11, which contributes to improved antitumor efficacy. Finally, these nanoparticle drugs are potentially less toxic in animals than CPT-11, as evidenced by the low incidence of bloody diarrhea and attenuated colonic damage. Overall, these results demonstrate that precisely engineered therapeutic nanoparticles are capable of enhancing efficacy, addressing the risk of tumor recurrence, and increasing drug tolerance, thus deserving further investigation.

A simple, rapid and low-cost spectrophotometric method for irinotecan quantification in human plasma and in pharmaceutical dosage forms

Irinotecan is an anticancer drug for which significant benefits from personalised dosing are expected. Quick procedures are therefore essential for monitoring irinotecan in treated patients. The objective of this work was to develop and validate a rapid and simple visible spectrophotometric method for quantitative determination of irinotecan in pharmaceutical dosage forms and to further investigate its usefulness for irinotecan analysis in plasma. Based on the shift of the irinotecan 355/368 nm-peak at very low pH (0.2) to 400 nm, we established a linear relationship between absorbance at 400 nm and irinotecan concentration in dilutions of an irinotecan solution for injection (R2 ≥ 0.999) and in plasma containing irinotecan (R2 ≥ 0.995). Background absorbance correction at 455 nm was essential to minimise background interference, solely in plasma samples. We fully validated the assay for quality control of the irinotecan solution in the injection dosage form: the standard curve was linear over the concentration range of 0.90 to at least 37.00 μg ml-1. The CV% on all quality control levels was determined to be ≤5.81% for repeatability and ≤6.62% for intermediate precision. Recovery was between 96.5% and 101.9%. Upon comparison with the LC/UV method, we demonstrated very good agreement and acceptable bias between the two methods (slope 0.973, y-intercept 0.0064). Similarly, the technical parameters of the assay in plasma satisfied international guidelines for method validation: the useful analytical range was determined to be between 0.93 and at least 10.00 μg ml-1. This is suitable for quantifying irinotecan in the plasma of treated patients, in the upper region of its therapeutic window, to decide whether dose adjustment is required. Repeatability and intermediate precision (CV%) were within 4.49% and 9.91%, respectively. Recovery was between 96.3% and 103.8%. There was a lack of significant interference by mild hemolysis or by icterus. Irinotecan extraction efficiency from plasma was within 77.9-68.5%. Our results indicated that the proposed method allows quantitative determination of irinotecan plasma levels with acceptable analytical characteristics. The advantages of the proposed method in both matrices, in terms of specificity, rapidity, simplicity, environmental impact and cost effectiveness, are discussed.

Development and validation of a selective SPR aptasensor for the detection of anticancer drug irinotecan in human plasma samples

In this work, a surface plasmon resonance (SPR)-based assay for the quantification of antineoplastic drug irinotecan in human plasma samples has been developed for the first time. The selective binding of irinotecan with an aptamer receptor, operating in human plasma, allowed to set-up a novel analytical methodology to detect the drug in the analytical range of interest by using SPR as detection technique. After hybridizing the aptamer to the sensing platform and optimizing the sample preparation procedure, a quantitative assay was validated according to FDA regulatory guidelines. The analytical working range was found between 100 and 7500 ng mL^-1 with negligible interferences from plasma components and co-medication associated with the administration of irinotecan. The utility of the new SPR assay was confirmed by analyzing plasma samples in parallel with LC-MS as reference technique, providing a new analytical tool for the therapeutic drug monitoring of irinotecan in patients under chemotherapy regimens.

Vulnerability to low-dose combination of irinotecan and niraparib in ATM-mutated colorectal cancer

BACKGROUND

Despite the advancements in new therapies for colorectal cancer (CRC), chemotherapy still constitutes the mainstay of the medical treatment. For this reason, new strategies to increase the efficacy of chemotherapy are desirable. Poly-ADP-Ribose Polymerase inhibitors (PARPi) have shown to increase the activity of DNA damaging chemotherapeutics used in the treatment of CRC, however previous clinical trials failed to validate these results and pointed out dose-limiting toxicities that hamper the use of such combinations in unselected CRC patients. Nevertheless, in these studies little attention was paid to the mutational status of homologous recombination repair (HRR) genes.

METHODS

We tested the combination of the PARPi niraparib with either 5-fluorouracil, oxaliplatin or irinotecan (SN38) in a panel of 12 molecularly annotated CRC cell lines, encompassing the 4 consensus molecular subtypes (CMSs). Synergism was calculated using the Chou-Talalay method for drug interaction. A correlation between synergism and genetic alterations in genes involved in homologous recombination (HR) repair was performed. We used clonogenic assays, mice xenograft models and patient-derived 3D spheroids to validate the results. The induction of DNA damage was studied by immunofluorescence.

RESULTS

We showed that human CRC cell lines, as well as patient-derived 3D spheroids, harboring pathogenic ATM mutations are significantly vulnerable to PARPi/chemotherapy combination at low doses, regardless of consensus molecular subtypes (CMS) and microsatellite status. The strongest synergism was shown for the combination of niraparib with irinotecan, and the presence of ATM mutations was associated to a delay in the resolution of double strand breaks (DSBs) through HRR and DNA damage persistence.

CONCLUSIONS

This work demonstrates that a numerically relevant subset of CRCs carrying heterozygous ATM mutations may benefit from the combination treatment with low doses of niraparib and irinotecan, suggesting a new potential approach in the treatment of ATM-mutated CRC, that deserves to be prospectively validated in clinical trials.

Patient-derived organoids can predict response to chemotherapy in metastatic colorectal cancer patients

There is a clear and unmet clinical need for biomarkers to predict responsiveness to chemotherapy for cancer. We developed an in vitro test based on patient-derived tumor organoids (PDOs) from metastatic lesions to identify nonresponders to standard-of-care chemotherapy in colorectal cancer (CRC). In a prospective clinical study, we show the feasibility of generating and testing PDOs for evaluation of sensitivity to chemotherapy. Our PDO test predicted response of the biopsied lesion in more than 80% of patients treated with irinotecan-based therapies without misclassifying patients who would have benefited from treatment. This correlation was specific to irinotecan-based chemotherapy, however, and the PDOs failed to predict outcome for treatment with 5-fluorouracil plus oxaliplatin. Our data suggest that PDOs could be used to prevent cancer patients from undergoing ineffective irinotecan-based chemotherapy.

Fluorescent Imprinted Nanoparticles for the Effective Monitoring of Irinotecan in Human Plasma

Fluorescent, imprinted nanosized polymers for the detection of irinotecan have been synthesised using a napthalimide polymerisable derivative (2-allyl-6-[2-(aminoethyl)-amino] napthalimide) as functional monomer. The imprinted polymers contain ethylene glycol dimethacrylate (EGDMA) as a cross-linker and were prepared by high dilution radical polymerisation in dimethylsulphoxide (DMSO). The material was able to rebind irinotecan up to 18 nmol/mg with good specificity. Fluorescence emission at 525 nm (excitation at 448 nm) was quenched by increasing concentrations of irinotecan via a static mechanism and also in analytically useful environments as mixtures of human plasma and organic solvents. This allowed the direct detection of irinotecan (in the 10 nM-30 µM range) in human plasma treated with acetonitrile; the limit of detection (LOD) was 9.4 nM, with within-run variability of 10% and day-to-day variability of 13%.

Site-specific contribution of Toll-like receptor 4 to intestinal homeostasis and inflammatory disease

Toll-like receptor 4 (TLR4) is a highly conserved protein of innate immunity, responsible for the regulation and maintenance of homeostasis, as well as immune recognition of external and internal ligands. TLR4 is expressed on a variety of cell types throughout the gastrointestinal tract, including on epithelial and immune cell populations. In a healthy state, epithelial cell expression of TLR4 greatly assists in homeostasis by shaping the host microbiome, promoting immunoglobulin A production, and regulating follicle-associated epithelium permeability. In contrast, immune cell expression of TLR4 in healthy states is primarily centred on the maturation of dendritic cells in response to stimuli, as well as adequately priming the adaptive immune system to fight infection and promote immune memory. Hence, in a healthy state, there is a clear distinction in the site-specific roles of TLR4 expression. Similarly, recent research has indicated the importance of site-specific TLR4 expression in inflammation and disease, particularly the impact of epithelial-specific TLR4 on disease progression. However, the majority of evidence still remains ambiguous for cell-specific observations, with many studies failing to provide the distinction of epithelial versus immune cell expression of TLR4, preventing specific mechanistic insight and greatly impacting the translation of results. The following review provides a critical overview of the current understanding of site-specific TLR4 activity and its contribution to intestinal/immune homeostasis and inflammatory diseases.

Characterization of Meta-Iodobenzylguanidine (mIBG) Transport by Polyspecific Organic Cation Transporters: Implication for mIBG Therapy

Radiolabeled meta-iodobenzylguanidine (mIBG) is an important radiopharmaceutical used in the diagnosis and treatment of neuroendocrine cancers. mIBG is known to enter tumor cells through the norepinephrine transporter. Whole-body scintigraphy has shown rapid mIBG elimination through the kidney and high accumulation in several normal tissues, but the underlying molecular mechanisms are unclear. Using transporter-expressing cell lines, we show that mIBG is an excellent substrate for human organic cation transporters 1-3 (hOCT1-3) and the multidrug and toxin extrusion proteins 1 and 2-K (hMATE1/2-K), but not for the renal organic anion transporter 1 and 3 (hOAT1/3). Kinetic analysis revealed that hOCT1, hOCT2, hOCT3, hMATE1, and hMATE2-K transport mIBG with similar apparent affinities (K _m of 19.5 ± 6.9, 17.2 ± 2.8, 14.5 ± 7.1, 17.7 ± 10.9, 12.6 ± 5.6 µM, respectively). Transwell studies in hOCT2/hMATE1 double-transfected Madin-Darby canine kidney cells showed that mIBG transport in the basal (B)-to-apical (A) direction is much greater than in the A-to-B direction. Compared with control cells, the B-to-A permeability of mIBG increased by 20-fold in hOCT2/hMATE1 double-transfected cells. Screening of 23 drugs used in the treatment of neuroblastoma identified several drugs with the potential to inhibit hOCT- or hMATE-mediated mIBG uptake. Interestingly, irinotecan selectively inhibited hOCT1, whereas crizotinib potently inhibited hOCT3-mediated mIBG uptake. Our results suggest that mIBG undergoes renal tubular secretion mediated by hOCT2 and hMATE1/2-K, and hOCT1 and hOCT3 may play important roles in mIBG uptake into normal tissues. SIGNIFICANCE STATEMENT: mIBG is eliminated by the kidney and extensively accumulates in several tissues known to express hOCT1 and hOCT3. Our results suggest that hOCT2 and human multidrug and toxin extrusion proteins 1 and 2-K are involved in mIBG renal elimination, whereas hOCT1 and hOCT3 may play important roles in mIBG uptake into normal tissues. These findings may help to predict and prevent adverse drug interaction with therapeutic [¹³¹I]mIBG and develop clinical strategies to reduce [¹³¹I]mIBG accumulation and toxicity in normal tissues and organs.

A 96-well culture platform enables longitudinal analyses of engineered human skeletal muscle microtissue strength

Three-dimensional (3D) in vitro models of human skeletal muscle mimic aspects of native tissue structure and function, thereby providing a promising system for disease modeling, drug discovery or pre-clinical validation, and toxicity testing. Widespread adoption of this research approach is hindered by the lack of easy-to-use platforms that are simple to fabricate and that yield arrays of human skeletal muscle micro-tissues (hMMTs) in culture with reproducible physiological responses that can be assayed non-invasively. Here, we describe a design and methods to generate a reusable mold to fabricate a 96-well platform, referred to as MyoTACTIC, that enables bulk production of 3D hMMTs. All 96-wells and all well features are cast in a single step from the reusable mold. Non-invasive calcium transient and contractile force measurements are performed on hMMTs directly in MyoTACTIC, and unbiased force analysis occurs by a custom automated algorithm, allowing for longitudinal studies of function. Characterizations of MyoTACTIC and resulting hMMTs confirms the capability of the device to support formation of hMMTs that recapitulate biological responses. We show that hMMT contractile force mirrors expected responses to compounds shown by others to decrease (dexamethasone, cerivastatin) or increase (IGF-1) skeletal muscle strength. Since MyoTACTIC supports hMMT long-term culture, we evaluated direct influences of pancreatic cancer chemotherapeutics agents on contraction competent human skeletal muscle myotubes. A single application of a clinically relevant dose of Irinotecan decreased hMMT contractile force generation, while clear effects on myotube atrophy were observed histologically only at a higher dose. This suggests an off-target effect that may contribute to cancer associated muscle wasting, and highlights the value of the MyoTACTIC platform to non-invasively predict modulators of human skeletal muscle function.

Concomitant intraperitoneal and systemic chemotherapy for extensive peritoneal metastases of colorectal origin: protocol of the multicentre, open-label, phase I, dose-escalation INTERACT trial

INTRODUCTION

Cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (CRS-HIPEC) has become standard of care for patients with peritoneal metastases of colorectal origin with a low/moderate abdominal disease load. In case of a peritoneal cancer index (PCI) score >20, CRS-HIPEC is not considered to be beneficial. Patients with a PCI >20 are currently offered palliative systemic chemotherapy. Previous studies have shown that systemic chemotherapy is less effective against peritoneal metastases than it is against haematogenous spread of colorectal cancer. It is suggested that patients with peritoneal metastases may benefit from the addition of intraperitoneal chemotherapy to systemic chemotherapy. Aim of this study is to establish the maximum tolerated dose of intraperitoneal irinotecan, added to standard of care systemic therapy for colorectal cancer. Secondary endpoints are to determine the safety and feasibility of this treatment and to establish the pharmacokinetic profile of intraperitoneally administered irinotecan.

METHODS AND ANALYSIS

This phase I, '3+3' dose-escalation, study is performed in two Dutch tertiary referral centres. The study population consists of adult patients with extensive peritoneal metastases of colorectal origin who have a good performance status and no extra-abdominal metastases. According to standard work-up for CRS-HIPEC, patients will undergo a diagnostic laparoscopy to score the PCI. In case of a PCI >20, a peritoneal access port will be placed in the abdomen of the patient. Through this port we will administer intraperitoneal irinotecan, in combination with standard systemic treatment consisting of 5-fluorouracil/leucovorin with oxaliplatin and the targeted agent bevacizumab. Therapy consists of a maximum of 12 cycles 2-weekly.

ETHICS AND DISSEMINATION

This study protocol is approved by a research medical ethics committee (Rotterdam, Netherlands) and the Dutch Competent Authority (CCMO, The Hague, Netherlands). The results of this trial will be submitted for publication in a peer-reviewed scientific journal.

TRAIL REGISTRATION NUMBER

NL6988 and NL2018-000479-33; Pre-results.

Seconds-resolved pharmacokinetic measurements of the chemotherapeutic irinotecan in situ in the living body

The ability to measure drugs in the body rapidly and in real time would advance both our understanding of pharmacokinetics and our ability to optimally dose and deliver pharmacological therapies. To this end, we are developing electrochemical aptamer-based (E-AB) sensors, a seconds-resolved platform technology that, as critical for performing measurements in vivo, is reagentless, reversible, and selective enough to work when placed directly in bodily fluids. Here we describe the development of an E-AB sensor against irinotecan, a member of the camptothecin family of cancer chemotherapeutics, and its adaptation to in vivo sensing. To achieve this we first re-engineered (via truncation) a previously reported DNA aptamer against the camptothecins to support high-gain E-AB signaling. We then co-deposited the modified aptamer with an unstructured, redox-reporter-modified DNA sequence whose output was independent of target concentration, rendering the sensor's signal gain a sufficiently strong function of square-wave frequency to support kinetic-differential-measurement drift correction. The resultant, 200 μm-diameter, 3 mm-long sensor achieves 20 s-resolved, multi-hour measurements of plasma irinotecan when emplaced in the jugular veins of live rats, thus providing an unprecedentedly high-precision view into the pharmacokinetics of this class of chemotherapeutics.

Pharmacokinetic and Pharmacogenetic Markers of Irinotecan Toxicity

BACKGROUND

Irinotecan (IRI) is a widely used chemotherapeutic drug, mostly used for first-line treatment of colorectal and pancreatic cancer. IRI doses are usually established based on patient's body surface area, an approach associated with large inter-individual variability in drug exposure and high incidence of severe toxicity. Toxic and therapeutic effects of IRI are also due to its active metabolite SN-38, reported to be up to 100 times more cytotoxic than IRI. SN-38 is detoxified by the formation of SN-38 glucuronide, through UGT1A1. Genetic polymorphisms in the UGT1A1 gene are associated to higher exposures to SN-38 and severe toxicity. Pharmacokinetic models to describe IRI and SN-38 kinetic profiles are available, with few studies exploring pharmacokinetic and pharmacogenetic-based dose individualization. The aim of this manuscript is to review the available evidence supporting pharmacogenetic and pharmacokinetic dose individualization of IRI in order to reduce the occurrence of severe toxicity during cancer treatment.

METHODS

The PubMed database was searched, considering papers published in the period from 1995-2017, using the keywords irinotecan, pharmacogenetics, metabolic genotyping, dose individualization, therapeutic drug monitoring, pharmacokinetics and pharmacodynamics, either alone or in combination, with original papers being selected based on the presence of relevant data.

CONCLUSION

The findings of this review confirm the importance of considering individual patient characteristics to select IRI doses. Currently, the most straightforward approach for IRI dose individualization is UGT1A1 genotyping. However, this strategy is sub-optimal due to several other genetic and environmental contributions to the variable pharmacokinetics of IRI and its active metabolite. The use of dried blood spot sampling could allow the clinical application of limited sampling and population pharmacokinetic models for IRI doses individualization.

Species-specific optimization of PEG~SN-38 prodrug pharmacokinetics and antitumor effects in a triple-negative BRCA1-deficient xenograft

PURPOSE

Optimal efficacy of a macromolecular prodrug requires balancing the rate of drug release with the rate of prodrug elimination. Since circulating macromolecules have different elimination rates in different species, a prodrug optimal for one species will likely not be for another. The objectives of this work were (a) to develop an approach to optimize pharmacokinetics of a PEG~SN-38 prodrug in a particular species, (b) to use the approach to predict the pharmacokinetics of various prodrugs of SN-38 in the mouse and human, and (c) to develop a PEG~SN-38 conjugate that is optimized for mouse tumor models.

METHODS

We developed models that describe the pharmacokinetics of a drug released from a prodrug by the relationship between the rates of drug release and elimination of the prodrug. We tested the model by varying the release rate of SN-38 from PEG~SN-38 conjugates in the setting of a constant prodrug elimination rate in the mouse. Finally, we tested the antitumor efficacy of a PEG~SN-38 optimized for the mouse.

RESULTS

Optimization of a PEG~SN-38 prodrug was achieved by adjusting the rate of SN-38 release such that the ratio of t_1/2,β of released SN-38 to the t_1/2 of prodrug elimination was 0.2-0.8. Using this approach, we could rationalize the efficacy of previous PEGylated SN-38 prodrugs in the mouse and human. Finally, a mouse-optimized PEG~SN-38 showed remarkable antitumor activity in BRCA1-deficient MX-1 xenografts; a single dose gave tumor regression, suppression, and shrinkage of massive tumors.

CONCLUSIONS

The efficacy of a macromolecular prodrug can be optimized for a given species by balancing the rate of drug release from the carrier with the rate of prodrug elimination.

Sequentially responsive biomimetic nanoparticles with optimal size in combination with checkpoint blockade for cascade synergetic treatment of breast cancer and lung metastasis

Recently, photodynamic therapy (PDT) emerges as a promising way to initiate immune response and being used in combination with chemotherapy. However, the antitumor effect is restricted due to the poor tumor penetration and retention, premature drug release and immunosuppressive environment of tumor sites. And as the size of nanoparticles plays a key role in drug delivery, series of hyaluronidase-responsive size-reducible biomimetic nanoparticles (mCAuNCs@HA) with different initial sizes are synthesized, and the optimal size of 150 nm is screened out because of the best blood circulation, tumor penetration and retention. Then the photosensitizer pheophorbide A and ROS-responsive paclitaxel dimer prodrug (PXTK) are co-loaded to facilitate on-demand drug release. The hydrolysis byproduct cinnamaldehyde in turn stimulates the ROS production by mitochondria, which compensates for the ROS consumed in the hydrolysis process. Anti-PD-L1 peptide (dPPA) is furthered loaded to alleviate the immunosuppressive environment of tumor and enhance the function of cytotoxic T lymphocytes activated by PDT-induced immunogenic cell death. The combination therapy activates CD4⁺, CD8⁺ T cells and NK cells and enhances secretion of cytokines (TNF-α and IL-12) with tumor inhibition rate increased to 84.2% and no metastasis is observed, providing a viable combination therapy for better anti-tumor and anti-metastasis efficacy.

Hepatic arterial infusion of irinotecan and EmboCept® S results in high tumor concentration of SN-38 in a rat model of colorectal liver metastases

Intraarterial chemotherapy for colorectal liver metastases (CRLM) can be applied alone or together with embolization particles. It remains unclear whether different types of embolization particles lead to higher intratumoral drug concentration. Herein, we quantified the concentrations of CPT-11 and its active metabolite SN-38 in plasma, liver and tumor tissue after hepatic arterial infusion (HAI) of irinotecan, with or without further application of embolization particles, in a rat model of CRLM. Animals underwent either systemic application of irinotecan, or HAI with or without the embolization particles Embocept^® S and Tandem™. Four hours after treatment concentrations of CPT-11 and SN-38 were analyzed in plasma, tumor and liver samples by high-performance liquid chromatography. Additionally, DNA-damage and apoptosis were analyzed immunohistochemically. Tumor tissue concentrations of SN-38 were significantly increased after HAI with irinotecan and EmboCept^® S compared to the other groups. The number of apoptotic cells was significantly higher after both HAI with irinotecan and EmboCept^® S or Tandem™ loaded with irinotecan compared to the control group. HAI with irinotecan and EmboCept^® S resulted in an increased SN-38 tumor concentration. Both HAI with irinotecan and EmboCept^® S or Tandem™ loaded with irinotecan were highly effective with regard to apoptosis.