A phase I and pharmacokinetic study of oral lapatinib administered once or twice daily in patients with solid malignancies

ErbB2-NOTCH1 axis controls autophagy in cardiac cells

Although the epidermal growth factor receptor 2 (ErbB2) and Notch1 signaling pathways have both significant roles in regulating cardiac biology, their interplay in the heart remains poorly investigated. Here, we present evidence of a crosstalk between ErbB2 and Notch1 in cardiac cells, with effects on autophagy and proliferation. Overexpression of ErbB2 in H9c2 cardiomyoblasts induced Notch1 activation in a post-transcriptional, p38-dependent manner, while ErbB2 inhibition with the specific inhibitor, lapatinib, reduced Notch1 activation. Moreover, incubation of H9c2 cells with lapatinib resulted in stalled autophagic flux and decreased proliferation, consistent with the established cardiotoxicity of this and other ErbB2-targeting drugs. Confirming the findings in H9c2 cells, exposure of primary neonatal mouse cardiomyocytes to exogenous neuregulin-1, which engages ErbB2, stimulated proliferation, and this effect was abrogated by concomitant inhibition of the enzyme responsible for Notch1 activation. Furthermore, the hearts of transgenic mice specifically overexpressing ErbB2 in cardiomyocytes had increased levels of active Notch1 and of Notch-related genes. These data expand the knowledge of ErbB2 and Notch1 functions in the heart and may allow better understanding the mechanisms of the cardiotoxicity of ErbB2-targeting cancer treatments.

Lapatinib dysregulates HER2 signaling and impairs the viability of human uveal melanoma cells

Uveal melanoma (UM) is the principal type of intraocular malignancy in adults. Up to 50% of UM patients develop metastatic disease with very poor survival. There are few drugs available to treat the primary or metastatic UM. This study was undertaken to evaluate the anti-cancer effect of lapatinib and corroborate the potential of HER2 inhibition in the treatment of UM. The anti-UM activity of lapatinib was assessed using cell viability, cell death and cell cycle analysis, and its anti-metastatic actions were evaluated using would healing, invasion and colony formation assays. Immunoblotting was used to substantiate the actions of lapatinib on apoptotic and HER2 signaling. The anti-UM activity of lapatinib was further evaluated in a UM xenograft mouse model. Lapatinib decreased the viability of four UM cell lines (IC50: 3.67-6.53 µM). The antiproliferative activity of lapatinib was corroborated in three primary cell lines isolated from UM patient tumors. In UM cell lines, lapatinib promoted apoptosis and cell cycle arrest, and strongly inhibited cell migration, invasion and reproductive cell growth. Lapatinib dysregulated HER2-AKT/ERK/PI3K signalling leading to the altered expression of apoptotic factors and cell cycle mediators in UM cell lines. Importantly, lapatinib suppressed tumourigenesis in mice carrying UM cell xenografts. Together the present findings are consistent with the assertion that HER2 is a viable therapeutic target in UM. Lapatinib is active in primary and metastatic UM as a clinically approved HER2 inhibitor. The activity of lapatinib in UM patients could be evaluated in future clinical trials.

Dosing Recommendation Based on the Effects of Different Meal Types on Pexidartinib Pharmacokinetics in Healthy Subjects: Implementation of Model-informed Drug Development Strategy

Pexidartinib, an oral small molecule inhibitor of the colony-stimulating factor 1 receptor, is approved for treatment of adults with symptomatic tenosynovial giant cell tumor associated with severe morbidity or functional limitations and not amenable to improvement with surgery. The original dosing regimen is 400 mg of pexidartinib (2 × 200-mg capsules) twice daily, administered on an empty stomach at least 1 hour before or 2 hours after a meal or snack. Because pexidartinib is likely to be taken over an extended period of time, the ability to take pexidartinib with a meal would simplify timing of administration and potentially improve compliance. Since administering 400 mg of pexidartinib with a low-fat meal increases exposure by ≈60% relative to the fasted state, administering 250 mg of pexidartinib with a low-fat meal (low-fat meal dosing regimen) was predicted to achieve an exposure similar to 400 mg administered during a fasted state (original dosing regimen). Based on clinical trial simulations with two one-sided t-tests and bootstrapping (ie, resampling) analyses, a bioequivalence study (n = 24) would have >90% power to conclude that the original dosing regimen (400 mg fasted twice daily) and the low-fat meal dosing regimen (250 mg with a low-fat meal twice daily) are bioequivalent. This report provides the outcome of the implementation of the model-informed drug development strategy to recommend and justify a low-fat meal dosing regimen for pexidartinib that has the potential to improve patient compliance while maintaining drug exposure.

Evaluation of Lapatinib-Loaded Microfibers Prepared by Centrifugal Spinning

Lapatinib (Lap) is a lypophilic drug frequently used in cancer treatment; however, due to its limited solubility and permeability, achieving therapeutic dose through oral administration proves to be a challenge. There are various methods for enhancing the solubility of Lap and other similar drugs, one being the preparation of amorphous solid dispersions (ASD). In this study, a Lap-loaded polyvinylpyrrolidone (PVP) fiber mat was created with centrifugal spinning from a PVP/Lap solution in dimethyl formamide and ethanol. The production rate was 12.2 g/h dry fibers, and the fibers had an average thickness of 2.55 ± 0.92 μm. In the differential scanning calorimetry (DSC) thermogram of the fiber mat, the melting peak of the crystalline Lap was not visible, suggesting that Lap was in an amorphous state. A dissolution study was carried out in 0.2 M phosphate buffer saline solution at 37 °C. UV spectrophotometry data indicated that in the sample containing the fiber mat, the Lap concentration was 332 μg/mL (66%) in 10 min, decreasing to 227 μg/mL by 45 min. Meanwhile the crystalline Lap formed a 30-40 μg/mL (6-8%) solution in 5 min, maintaining that concentration. We conclude that centrifugal spinning can be an effective and easy method to produce ASDs.

Polymeric nanoparticles targeting Sialyl-Tn in gastric cancer: A live tracking under flow conditions

Drug delivery using nanoparticles (NPs) represents a potential approach for therapy in cancer, such gastric cancer (GC) due to their targeting ability and controlled release properties. The use of advanced nanosystems that deliver anti-cancer drugs specifically to tumor cells may strongly rely on the expression of cancer-associated targets. Glycans aberrantly expressed by cancer cells are attractive targets for such delivery strategy. Sialylated glycans, such as Sialyl-Tn (STn) are aberrantly expressed in several epithelial tumors, including GC, being a potential target for a delivery nanosystem. The aim of this study was the development of NPs surface-functionalized with a specific antibody targeting the STn glycan and further evaluate this nanosystem effectiveness regarding its specificity and recognition capacity. Our results showed that the NPs surface-functionalized with anti-STn antibody efficiently are recognized by cells displaying the cancer-associated STn antigen under static and live cell monitoring flow conditions. This uncovers the potential use of such NPs for drug delivery in cancer. However, flow exposure was disclosed as an important biomechanical parameter to be taken into consideration. Here we presented an innovative and successful methodology to live track the NPs targeting STn antigen under shear stress, simulating the physiological flow. We demonstrate that unspecific binding of NPs agglomerates did not occur under flow conditions, in contrast with static assays. This robust approach can be applied for in vitro drug studies, giving valuable insights for in vivo studies.

Treatment of Painful Palmoplantar Keratoderma Related to Pachyonychia Congenita Using EGFR Inhibitors

Pachyonychia congenita (PC) is a genodermatosis associated with severe painful palmoplantar keratoderma (PPK) and thickened dystrophic nails caused by autosomal dominant-negative mutations in five genes encoding keratins 6A-B-C, 16, and 17. The mechanical, surgical, or medical options for painful PC are inefficient. Given ErbB/Her family members’ role in epidermal homeostasis, this study sought to investigate the possibility of treating PC patients with PPK by blocking signaling either with EGFR (Her1) inhibitor erlotinib or lapatinib, a dual EGFR(Her1)/Her2. After 1 month of therapy with oral erlotinib treatment at 75 mg/day, the pain disappeared for patient #1, with partially reduced hyperkeratosis, while increasing the dose to 100 mg/day resulted in painful skin fissures. Therapy replacement with erlotinib cream at 0.2% was inconclusive, and substitution with oral lapatinib at alternating doses of 500 and 750 mg/day achieved a good compromise between pain reduction, symptom improvements, and side effects. Patient #2′s treatment with erlotinib cream failed to display significant improvements. Oral erlotinib started at 75 mg/day then reduced to 25 mg/day because of the formation of an acneiform rash. Treatment considerably improved the patient’s condition, with an almost complete disappearance of pain. Oral Her1 or 1/2 inhibitors reduced pain, improved two PC patients’ quality of life, and offered promising therapeutic perspectives.

Therapeutic Drug Monitoring of Protein Kinase Inhibitors in Breast Cancer Patients

Protein kinase inhibitors (PKIs) represent up-to-date therapeutic approach in breast cancer treatment. Although cancer is a rapidly progressive disease, many substances, including PKIs, are usually used at fixed doses without regard to each patient's individuality. Therapeutic drug monitoring (TDM) is a tool that allows individualization of therapy based on drug plasma levels. For TDM conduct, exposure-response relationships of drug substances are required. The pharmacokinetic data and exposure-response evidence supporting the use of TDM for 6 PKIs used in breast cancer treatment, one of the most common female tumour diseases, are discussed in this review.

Human induced pluripotent stem cell-derived platelets loaded with lapatinib effectively target HER2+ breast cancer metastasis to the brain

Prognosis of patients with HER2+ breast-to-brain-metastasis (BBM) is dismal even after current standard-of-care treatments, including surgical resection, whole-brain radiation, and systemic chemotherapy. Radiation and systemic chemotherapies can also induce cytotoxicity, leading to significant side effects. Studies indicate that donor-derived platelets can serve as immune-compatible drug carriers that interact with and deliver drugs to cancer cells with fewer side effects, making them a promising therapeutic option with enhanced antitumor activity. Moreover, human induced pluripotent stem cells (hiPSCs) provide a potentially renewable source of clinical-grade transfusable platelets that can be drug-loaded to complement the supply of donor-derived platelets. Here, we describe methods for ex vivo generation of megakaryocytes (MKs) and functional platelets from hiPSCs (hiPSC-platelets) in a scalable fashion. We then loaded hiPSC-platelets with lapatinib and infused them into BBM tumor-bearing NOD/SCID mouse models. Such treatment significantly increased intracellular lapatinib accumulation in BBMs in vivo, potentially via tumor cell-induced activation/aggregation. Lapatinib-loaded hiPSC-platelets exhibited normal morphology and function and released lapatinib pH-dependently. Importantly, lapatinib delivery to BBM cells via hiPSC-platelets inhibited tumor growth and prolonged survival of tumor-bearing mice. Overall, use of lapatinib-loaded hiPSC-platelets effectively reduced adverse effects of free lapatinib and enhanced its therapeutic efficacy, suggesting that they represent a novel means to deliver chemotherapeutic drugs as treatment for BBM.

Single-Dose Pharmacokinetics and Tolerability of the Oral Epidermal Growth Factor Receptor Inhibitor Mobocertinib (TAK-788) in Healthy Volunteers: Low-Fat Meal Effect and Relative Bioavailability of 2 Capsule Products

Mobocertinib (TAK‐788) is a tyrosine kinase inhibitor under investigation for treatment of non–small cell lung cancer with activating EGFR exon 20 insertions. This study examined the safety; tolerability; pharmacokinetics (PK), including food effects; and bioavailability of mobocertinib in healthy volunteers. In part 1, fasted volunteers were randomized to placebo or mobocertinib in single‐ascending‐dose cohorts (20‐160 mg). In part 2, mobocertinib (120/160 mg) was administered on day 1 of periods 1 and 2 under fasted or low‐fat meal conditions (2‐period, 2‐sequence crossover design). In part 3, fasted volunteers received mobocertinib 160 mg in 1 of 2 capsule products on day 1 of periods 1 and 2 with 7‐day washout. Safety and PK parameters were assessed. Sixty‐nine volunteers were enrolled (mean age, 29 years; 75% male). The most common adverse events (AEs; ≥10% of volunteers) were gastrointestinal AEs (25%‐50%) and headache (8%‐31%). No serious AEs were reported. A low‐fat meal did not affect the PK of mobocertinib or its active metabolites. The geometric mean terminal disposition phase half‐life (20 hours) supported once‐daily dosing. The 2 capsule products were bioequivalent. These data guided dosing and supported administration of mobocertinib without regard to low‐fat meal intake in ongoing and planned clinical studies.

Therapeutic drug monitoring of oral targeted antineoplastic drugs

PURPOSE

This review provides an overview of the current challenges in oral targeted antineoplastic drug (OAD) dosing and outlines the unexploited value of therapeutic drug monitoring (TDM). Factors influencing the pharmacokinetic exposure in OAD therapy are depicted together with an overview of different TDM approaches. Finally, current evidence for TDM for all approved OADs is reviewed.

METHODS

A comprehensive literature search (covering literature published until April 2020), including primary and secondary scientific literature on pharmacokinetics and dose individualisation strategies for OADs, together with US FDA Clinical Pharmacology and Biopharmaceutics Reviews and the Committee for Medicinal Products for Human Use European Public Assessment Reports was conducted.

RESULTS

OADs are highly potent drugs, which have substantially changed treatment options for cancer patients. Nevertheless, high pharmacokinetic variability and low treatment adherence are risk factors for treatment failure. TDM is a powerful tool to individualise drug dosing, ensure drug concentrations within the therapeutic window and increase treatment success rates. After reviewing the literature for 71 approved OADs, we show that exposure-response and/or exposure-toxicity relationships have been established for the majority. Moreover, TDM has been proven to be feasible for individualised dosing of abiraterone, everolimus, imatinib, pazopanib, sunitinib and tamoxifen in prospective studies. There is a lack of experience in how to best implement TDM as part of clinical routine in OAD cancer therapy.

CONCLUSION

Sub-therapeutic concentrations and severe adverse events are current challenges in OAD treatment, which can both be addressed by the application of TDM-guided dosing, ensuring concentrations within the therapeutic window.

QT Prolongation in Cancer Patients

Background: QT prolongation and torsades de pointes pose a major concern for cardiologists and oncologists. Although cancer patients are suspected to have prolonged QT intervals, this has not been investigated in a large population. The purpose of this study was to analyze the QT interval distribution in a cancer population and compare it to a non-cancer population in the same institution. Methods: The study was a retrospective review of 82,410 ECGs performed in cancer patients (51.8% women and 48.2% men) and 775 ECGs performed in normal stem cell donors (47.9% women and 52.1% men) from January 2009 to December 2013 at the University of Texas MD Anderson Cancer Center. Pharmacy prescription data was also collected and analyzed during the same time period. Correction of the QT interval for the heart rate was performed using the Bazett and Fridericia formulas. Results: After QT correction for heart rate by the Fridericia formula (QTcF), the mean and 99% percentile QTc for cancer patients were 414 and 473 ms, respectively. These were significantly longer than the normal stem cell donors, 407 and 458 ms, p < 0.001, respectively. Among the cancer patients, the QTc was longer in the inpatient setting when compared to both outpatient and emergency center areas. The most commonly prescribed QT prolonging medications identified were ondansetron and methadone. Conclusion: Our study demonstrates significantly longer QTc intervals in cancer patients, especially in the inpatient setting. Frequently prescribed QT prolonging medications such as antiemetics and analgesics may have a causative role in QT prolongation seen in our cancer hospital.

Experimental and computational evaluation of kolliphor RH 40 as a new fluorescence enhancer in development of a micellar-based spectrofluorimetric method for determination of lapatinib in tablets and urine

This study describes, for the first time, the experimental and computational investigations for evaluation of kolliphor RH 40 as a fluorescence enhancer surfactant in development of a spectrofluorimetric method for determination of lapatinib (LAP), a tyrosine kinase-inhibitor drug approved for targeted therapy of breast cancer. The investigations involved the ability of kolliphor RH 40 to form micelles with LAP and its enhancing effect on the weak native fluorescence of LAP at 420 nm after its excitation at 292 nm. Different variables were experimentally investigated: types of organized media, diluting solvent, buffer type and its pH value. The optimum values of the most influencing variables on the interaction of kolliphor RH 40 with LAP were refined by the computational response surface methodology (RSM). Under the optimized conditions, it was found that kolliphor RH 40 forms micelles with LAP, and its fluorescence enhancing ability was higher than other surfactants tested by ~ 10-folds. This micellar-enhanced effect of kolliphor RH 40 was employed in the development of a new sensitive spectrofluorimetric method for the accurate determination of LAP. The method was validated according to the guidelines of the International Conference on Harmonization (ICH) for validation of analytical procedures. The relative fluorescence intensity (RFI) was in excellent linear relationship (correlation coefficient was 0.998) with the LAP concentrations in the range of 50–1000 ng/mL. The method limit of detection (LOD) was 27.31 ng/mL and its accuracy was ≥ 99.82%. The method was successfully applied to the determination of LAP in its pharmaceutical tablets, tablets dissolution testing and content uniformity. The method application was extended to the determination of LAP in urine samples with an accuracy of 99.82 ± 3.45%. The method is considered as an eco-friendly green approach and more efficient alternative method to the existing analytical methodologies for determination of LAP.

Nanohydroxyapatite-Mediated Imatinib Delivery for Specific Anticancer Applications

In the present study, a nanoapatite-mediated delivery system for imatinib has been proposed. Nanohydroxyapatite (nHAp) was obtained by co-precipitation method, and its physicochemical properties in combination with imatinib (IM) were studied by means of XRPD (X-ray Powder Diffraction), SEM-EDS (Scanning Electron Microscopy-Energy Dispersive X-ray Spectroscopy), FT-IR (Fourier-Transform Infrared Spectroscopy), absorption spectroscopy as well as DLS (Dynamic Light Scattering) techniques. The obtained hydroxyapatite was defined as nanosized rod-shaped particles with high crystallinity. The amorphous imatinib was obtained by conversion of its crystalline form. The beneficial effects of amorphous pharmaceutical agents have been manifested in the higher dissolution rate in body fluids improving their bioavailability. Imatinib-to-hydroxyapatite interactions on the surface were confirmed by SEM images as well as absorption and FT-IR spectroscopy. The cytotoxicity of the system was tested on NI-1, L929, and D17 cell lines. The effectiveness of imatinib was not affected by nHAp modification. The calculated IC₅₀ values for drug-modified nHAp were similar to those for the drug itself. However, higher cytotoxicity was observed at higher concentrations of imatinib, in comparison with the drug alone.

Development of a Potent Brain-Penetrant EGFR Tyrosine Kinase Inhibitor against Malignant Brain Tumors

The epidermal growth factor receptor (EGFR) is genetically altered in nearly 60% of glioblastoma tumors; however, tyrosine kinase inhibitors (TKIs) against EGFR have failed to show efficacy for patients with these lethal brain tumors. This failure is attributed to the inability of clinically tested EGFR TKIs to cross the blood-brain barrier (BBB) and achieve adequate pharmacological levels to inhibit various oncogenic forms of EGFR that drive glioblastoma. Through SAR analysis, we developed compound 5 (JCN037) from an anilinoquinazoline scaffold by ring fusion of the 6,7-dialkoxy groups to reduce the number of rotatable bonds and polar surface area and by introduction of an ortho-fluorine and meta-bromine on the aniline ring for improved potency and BBB penetration. Relative to the conventional EGFR TKIs erlotinib and lapatinib, JCN037 displayed potent activity against EGFR amplified/mutant patient-derived cell cultures, significant BBB penetration (2:1 brain-to-plasma ratio), and superior efficacy in an EGFR-driven orthotopic glioblastoma xenograft model.

First-in-human, phase I single-ascending-dose study of the safety, pharmacokinetics, and relative bioavailability of selatinib, a dual EGFR-ErbB2 inhibitor in healthy subjects

We assessed the pharmacokinetics and safety of a single oral administration of selatinib to healthy Chinese subjects and evaluated the potential bioavailability advantage of selatinib relative to lapatinib. Healthy subjects aged 18-40 years were enrolled in this two-part study: Part 1, a single ascending dose (50-500 mg), randomized, double-blind, placebo-control study with 64 subjects; and Part 2, an open-label, positive control, randomized, three-treatment, three-period, three-sequence crossover design study, with 6 subjects administered a single 500-mg dose of selatinib tablets (A), selatinib suspension (B), or lapatinib tablets C) per cycle. In part 1, selatinib was well-tolerated up to the planned maximum dose of 500 mg; thus the maximum tolerated dose was not attained. Twenty-two adverse events were observed in 19 (36.5%) of the 52 subjects administered the test drug. The most common drug-related adverse event was diarrhea. The mean selatinib peak plasma concentration was 69.4-494 ng/mL, which was achieved in a median peak time of 3.5-4.5 h, with a mean elimination half-life between 13.8 and 15.8 h. In Part 2, A and B showed similar bioavailability. Plasma exposure to the active drug (selatinib plus the metabolite, lapatinib) after A intake was more than two-fold higher than that of the same dose of C. In the dose range of 50-500 mg, selatinib was safe and well-tolerated by healthy Chinese subjects, and it conformed with linear pharmacokinetics. Active exposure to selatinib was much greater than that to lapatinib, supporting its development as an adjuvant for anticancer treatment.

Administration of Lapatinib with Food Increases Its Plasma Concentration in Chinese Patients with Metastatic Breast Cancer: A Prospective Phase II Study

Lessons Learned

Administration of lapatinib with food significantly increased its plasma concentration in Chinese patients with metastatic breast cancer.

There were no serious adverse events during the study and no significant differences in lapatinib‐related adverse events between the fasted and fed states.

Background

Lapatinib, a small molecular reversible dual tyrosine kinase inhibitor of epidermal growth factor receptor (EGFR) and human epidermal growth receptor 2 (HER2), was approved for use in combination with capecitabine to treat metastatic HER2‐positive breast cancer. Administration of lapatinib in the fasted state was recommended; however, our preliminary phase II trial data showed that administration of lapatinib with food increased its concentration.

Methods

This study was a single‐center, open‐label, and prospective self‐controlled clinical study. Ten Chinese patients with metastatic breast cancer were enrolled from June 2017 to April 2018. They were required to receive lapatinib plus physician's choice of chemotherapy. Patients were required to take lapatinib orally on an empty stomach continually for 10 days, and then take lapatinib with food continually for the next 10 days. Plasma concentration was measured by liquid chromatography on the 9th and 10th day of each state.

Results

Area under the concentration‐time curve (AUC) of the fasted state and the fed state was 21.23 ± 8.91 mg*h/L (coefficient of variation (CV)% 42%) and 60.60 ± 16.64 mg*h/L (CV% 27%), respectively. The mean plasma concentration in the fasted state was 0.88 ± 0.39 mg/L (CV% 45%), and that in the fed state was 2.53 ± 0.77 mg/L (CV% 30%). Compared with taking lapatinib on an empty stomach, receiving lapatinib with food significantly increased the plasma concentration of lapatinib (Wilcoxon match‐paired test, p = .005). In addition, there were no serious adverse events during the study or significant difference in lapatinib‐related adverse events between the two states.

Conclusion

Our study shows that receiving lapatinib with food can increase its plasma concentration with no significantly increased drug‐related toxicity. We suggest that a larger‐sample‐size clinical trial is needed to fully understand the effect of administration of lapatinib with food.

Advances in nanotechnology-based delivery systems for EGFR tyrosine kinases inhibitors in cancer therapy

Oral tyrosine kinase inhibitors (TKIs) against epidermal growth factor receptor (EGFR) family have been introduced into the clinic to treat human malignancies for decades. Despite superior properties of EGFR-TKIs as small molecule targeted drugs, their applications are still restricted due to their low solubility, capricious oral bioavailability, large requirement of daily dose, high binding tendency to plasma albumin and initial/acquired drug resistance. Nanotechnology is a promising tool to improve efficacy of these drugs. Through non-oral routes. Various nanotechnology-based delivery approaches have been developed for providing efficient delivery of EGFR-TKIs with a better pharmacokinetic profile and tissue-targeting ability. This review aims to indicate the advantage of nanocarriers for EGFR-TKIs delivery.

Phase I Study of Intermittent High-Dose Lapatinib Alternating with Capecitabine for HER2-Positive Breast Cancer Patients with Central Nervous System Metastases

PURPOSE

Lapatinib and capecitabine cross the blood-tumor barrier in breast cancer brain metastasis but have modest clinical efficacy. Administration of high-dose tyrosine kinase inhibitor has been evaluated in brain metastases and primary brain tumors as a strategy to improve drug exposure in the central nervous system (CNS). We derived a rational drug scheduling of intermittent high-dose lapatinib alternating with capecitabine based on our preclinical data and Norton-Simon mathematical modeling. We tested this intermittent, sequential drug schedule in patients with breast cancer with CNS metastasis.

PATIENTS AND METHODS

We conducted a phase I trial using an accelerated dose escalation design in patients with HER2-positive (HER2+) breast cancer with CNS metastasis. Lapatinib was given on day 1-3 and day 15-17 with capecitabine on day 8-14 and day 22-28 on an every 28-day cycle. Lapatinib dose was escalated, and capecitabine given as a flat dose at 1,500 mg BID. Toxicity and efficacy were evaluated.

RESULTS

Eleven patients were enrolled: brain only (4 patients, 36%), leptomeningeal (5 patients, 45%), and intramedullary spinal cord (2 patients, 18%). Grade 3 nausea and vomiting were dose-limiting toxicities. The MTD of lapatinib was 1,500 mg BID. Three patients remained on therapy for greater than 6 months.

CONCLUSIONS

High-dose lapatinib is tolerable when given intermittently and sequentially with capecitabine. Antitumor activity was noted in both CNS and non-CNS sites of disease. This novel administration regimen is feasible and efficacious in patients with HER2+ breast cancer with CNS metastasis and warrants further investigation.

Interleukin-1 alpha increases anti-tumor efficacy of cetuximab in head and neck squamous cell carcinoma

BACKGROUND

Despite the high prevalence of epidermal growth factor receptor (EGFR) overexpression in head and neck squamous cell carcinomas (HNSCCs), incorporation of the EGFR inhibitor cetuximab into the clinical management of HNSCC has not led to significant changes in long-term survival outcomes. Therefore, the identification of novel therapeutic approaches to enhance the clinical efficacy of cetuximab could lead to improved long-term survival for HNSCC patients. Our previous work suggests that EGFR inhibition activates the interleukin-1 (IL-1) pathway via tumor release of IL-1 alpha (IL-1α), although the clinical implications of activating this pathway are unclear in the context of cetuximab therapy. Given the role of IL-1 signaling in anti-tumor immune response, we hypothesized that increases in IL-1α levels would enhance tumor response to cetuximab.

METHODS

Parental and stable myeloid differentiation primary response gene 88 (MyD88) and IL-1 receptor 1 (IL-1R1) knockdown HNSCC cell lines, an IL-1R antagonist (IL-1RA), neutralizing antibodies to IL-1α and IL-1β, and recombinant IL-1α and IL-1β were used to determine cytokine production (using ELISA) in response to cetuximab in vitro. IL-1 pathway modulation in mouse models was accomplished by administration of IL-1RA, stable overexpression of IL-1α in SQ20B cells, administration of rIL-1α, and administration of a polyanhydride nanoparticle formulation of IL-1α. CD4⁺ and CD8⁺ T cell-depleting antibodies were used to understand the contribution of T cell-dependent anti-tumor immune responses. Baseline serum levels of IL-1α were measured using ELISA from HNSCC patients treated with cetuximab-based therapy and analyzed for association with progression free survival (PFS).

RESULTS

Cetuximab induced pro-inflammatory cytokine secretion from HNSCC cells in vitro which was mediated by an IL-1α/IL-1R1/MyD88-dependent signaling pathway. IL-1 signaling blockade did not affect the anti-tumor efficacy of cetuximab, while increased IL-1α expression using polyanhydride nanoparticles in combination with cetuximab safely and effectively induced a T cell-dependent anti-tumor immune response. Detectable baseline serum levels of IL-1α were associated with a favorable PFS in cetuximab-based therapy-treated HNSCC patients compared to HNSCC patients with undetectable levels.

CONCLUSIONS

Altogether, these results suggest that IL-1α in combination with cetuximab can induce a T cell-dependent anti-tumor immune response and may represent a novel immunotherapeutic strategy for EGFR-positive HNSCCs.

Effects of Proton Pump Inhibitor Coadministration on the Plasma Concentration of Erlotinib in Patients With Non-Small Cell Lung Cancer

BACKGROUND

Erlotinib is used for treating non-small cell lung cancer (NSCLC). Intestinal absorption of erlotinib is impaired under gastric pH elevation; therefore, coadministration of gastric acid suppressants may provide lower blood concentration of erlotinib. We investigated the effects of erlotinib coadministration with proton pump inhibitors (PPIs) and histamine H2 receptor blockers (H2RBs) on the plasma concentration of erlotinib and erlotinib-induced adverse reaction in patients with NSCLC.

METHODS

Forty-two patients receiving erlotinib therapy for NSCLC were recruited for this study. Association of adverse reactions (rash and diarrhea) with plasma concentration of erlotinib was examined. Plasma concentration-to-dose (C/D) ratios and oral clearance (CL/F), which was estimated by population pharmacokinetic analysis of plasma concentrations of erlotinib, were compared among 3 patient groups: without coadministration of gastric acid suppressants (control group), with coadministration of PPI (PPI group), and coadministration of H2RB (H2RB group).

RESULTS

Patients with grade ≥2 rash had higher plasma concentrations of erlotinib compared with those with grade ≤1 [1.02 (0.43-2.60) versus 0.67 (0.10-1.85) mcg/mL, P < 0.01]. The C/D ratios of erlotinib in the PPI and H2RB groups were lower than that in the control group [0.39 (0.08-0.76) and 0.48 (0.33-0.81) versus 0.51 (0.28-1.28) mcg·mL·mg·kg], where statistical significance was observed between PPI and control groups (P < 0.05). The population pharmacokinetic estimated oral CL/F in the PPI and H2RB groups were higher than that in the control group [5.55 (3.36-14.52) and 4.82 (2.08-6.32) versus 3.95 (2.01-10.44) L/h], where statistical significance was observed between PPI and control groups (P < 0.05).

CONCLUSIONS

Plasma concentrations of erlotinib in patients under coadministration of gastric acid suppressants were lower than those without gastric acid suppressants through drug interaction, suppressing the intestinal absorption of erlotinib. The magnitude of this drug interaction was more pronounced in the coadministration of PPI compared with H2RB.

The HER2 inhibitor lapatinib potentiates doxorubicin-induced cardiotoxicity through iNOS signaling

Rationale: Lapatinib (LAP) is a crucial alternative to trastuzumab upon the onset of drug resistance during treatment of metastatic human epidermal growth factor receptor 2-positive breast cancer. Like trastuzumab, LAP is commonly used alongside anthracyclines as a combination therapy, due to enhanced anti-cancer efficacy. However, this is notably associated with cardiotoxicity so it is imperative to understand the mechanisms driving this cardiotoxicity and develop cardioprotective strategies. To this end, here we utilize human pluripotent stem cell-derived cardiomyocytes (hPSC-CMs), which exhibit several characteristics representative of in vivo cardiomyocytes that make them breakthrough models to study drug toxicity.

Methods: We investigated LAP- and doxorubicin (DOX)-induced toxicity in hPSC-CMs and evaluated the involvement of inducible nitric oxide (NO) synthase (iNOS). The significance of iNOS-mediated cardiotoxicity was furthermore evaluated in animal studies.

Results: LAP synergistically increased DOX toxicity in hPSC-CMs in a dose- and time-dependent manner. At concentrations that were otherwise non-apoptotic when administered separately, LAP significantly potentiated DOX-induced hPSC-CM apoptosis. This was accompanied by increased iNOS expression and pronounced production of NO. iNOS inhibition significantly reduced hPSC-CM sensitivity to LAP and DOX co-treatment (LAP-plus-DOX), leading to reduced apoptosis. Consistent with our observations in vitro, delivery of an iNOS inhibitor in mice treated with LAP-plus-DOX attenuated myocardial apoptosis and systolic dysfunction. Moreover, inhibition of iNOS did not compromise the anti-cancer potency of LAP-plus-DOX in a murine breast cancer xenograft model.

Conclusions: Our findings suggest that iNOS inhibition is a promising cardioprotective strategy to accompany HER2-inhibitor/anthracycline combination therapies. Furthermore, these results support the promise of hPSC-CMs as a platform for investigating cardiotoxicity and developing cardioprotectants as a whole.

Development of a method to determine axitinib, lapatinib and afatinib in plasma by micellar liquid chromatography and validation by the European Medicines Agency guidelines

A method based on micellar liquid chromatography to quantify the tyrosine kinase inhibitors axitinib, lapatinib and afatinib in plasma is reported. The sample pretreatment was a simple 1/5-dilution in a pure micellar solution, filtration and direct injection, without requiring extraction or purification steps. The three drugs were resolved from the matrix in 17min, using an aqueous solution of 0.07M sodium dodecyl sulfate - 6.0% 1-pentanol, buffered at pH7 with 0.01M phosphate salt as mobile phase, running under isocratic mode at 1mL/min through a C18 column. The detection was performed by absorbance at 260nm. An accurate mathematical relationship was established between the retention factor of each drug and the surfactant/organic solvent concentration in the mobile phase, achieved with a limited number of experiments, in order to optimize these factors. A binding behavior of the analytes face to the micelles was found out. The method was successfully validated by the guidelines of the European Medicines Agency in terms of: selectivity, linearity (r²>0.9995), calibration range (0.5 to 10mg/L), limit of detection (0.2mg/L), carry-over effect, accuracy (-8.1 to +6.9%), precision (<13.8%), dilution integrity, matrix effect, stability and robustness. The procedure was found reliable, practical, economic, accessible, short-time, easy-to-handle, inexpensive, environmental-friendly, safe, useful for the analysis of many samples per day. Finally, the method was applied to the analysis of incurred, using quality control samples in the same analytical run, with adequate results. Therefore, it can be implementable for routine analysis in clinical laboratories.

Mathematical modeling identifies optimum lapatinib dosing schedules for the treatment of glioblastoma patients

Human primary glioblastomas (GBM) often harbor mutations within the epidermal growth factor receptor (EGFR). Treatment of EGFR-mutant GBM cell lines with the EGFR/HER2 tyrosine kinase inhibitor lapatinib can effectively induce cell death in these models. However, EGFR inhibitors have shown little efficacy in the clinic, partly because of inappropriate dosing. Here, we developed a computational approach to model the in vitro cellular dynamics of the EGFR-mutant cell line SF268 in response to different lapatinib concentrations and dosing schedules. We then used this approach to identify an effective treatment strategy within the clinical toxicity limits of lapatinib, and developed a partial differential equation modeling approach to study the in vivo GBM treatment response by taking into account the heterogeneous and diffusive nature of the disease. Despite the inability of lapatinib to induce tumor regressions with a continuous daily schedule, our modeling approach consistently predicts that continuous dosing remains the best clinically feasible strategy for slowing down tumor growth and lowering overall tumor burden, compared to pulsatile schedules currently known to be tolerated, even when considering drug resistance, reduced lapatinib tumor concentrations due to the blood brain barrier, and the phenotypic switch from proliferative to migratory cell phenotypes that occurs in hypoxic microenvironments. Our mathematical modeling and statistical analysis platform provides a rational method for comparing treatment schedules in search for optimal dosing strategies for glioblastoma and other cancer types.

Lapatinib-loaded human serum albumin nanoparticles for the prevention and treatment of triple-negative breast cancer metastasis to the brain

Brain metastasis from triple-negative breast cancer (TNBC) has continued to lack effective clinical treatments until present. However, the feature of epidermal growth factor receptor (EGFR) frequently overexpressed in TNBC offers the opportunity to employ lapatinib, a dual-tyrosine kinase inhibitor of human epidermal growth factor receptor-2 (HER2) and EGFR, in the treatment of brain metastasis of TNBC. Unfortunately, the low oral bioavailability of lapatinib and drug efflux by blood-brain barrier have resulted in low drug delivery efficiency into the brain and limited therapeutic effects for patients with brain metastasis in clinical trials. To overcome such disadvantages, we developed lapatinib-loaded human serum albumin (HSA) nanoparticles, named LHNPs, by modified nanoparticle albumin-bound (Nab) technology. LHNPs had a core-shell structure and the new HSA/phosphatidylcholine sheath made LHNPs stable in bloodstream. Compared to free lapatinib, LHNPs could inhibit the adhesion, migration and invasion ability of high brain-metastatic 4T1 cells more effectively in vitro. Tissue distribution following intravenous administration revealed that LHNPs (i.v., 10 mg/kg) achieved increased delivery to the metastatic brain at 5.43 and 4.36 times the levels of Tykerb (p.o., 100 mg/kg) and lapatinib solution (LS, i.v., 10 mg/kg), respectively. Compared to the marketed Tykerb group, LHNPs had markedly better inhibition effects on brain micrometastasis and significantly extended the median survival time of 4T1 brain metastatic mice in consequence. The improved anti-tumor efficacy of LHNPs could be partly ascribed to down-regulating metastasis-related proteins. Therefore, these results clearly indicated that LHNPs could become a promising candidate for clinical applications against brain metastasis of TNBC.

Prediction of Apparent Oral Clearance of Small-Molecule Inhibitors in Pediatric Patients

The purpose of this study was to build regression models for the prediction of apparent oral clearance (CL/F) for small-molecule inhibitors in the pediatric population using data obtained from adults. Two approaches were taken; a simple allometric regression model which considers no interdrug or interindividual variability and an allometric regression model with mixed-effects modeling where some variability parameters are included in the model. Average CL/F values were obtained for 15 drugs at various dosages from 31 literatures (a total of 139 data sets) conducted in adults and for 15 drugs from 26 literatures (62 data sets) conducted in children. Data were randomly separated into the "modeling" or "validation" data set, and the 2 allometric regression models were applied to the modeling data set. The predictive ability of the models was examined by comparing the observed and model-predicted CL/F in children using the validation data set. The percentage root mean square error was 17.2% and 26.3% in the simple allometric regression model and the allometric regression model with mixed-effects modeling, respectively. The predictive ability of the 2 models seems acceptable, suggesting that they could be useful for predicting the CL/F of new small-molecule inhibitors and for determining adequate doses in clinical pharmacotherapy for children.

CD44 targeting hyaluronic acid coated lapatinib nanocrystals foster the efficacy against triple-negative breast cancer

Lapatinib (LPT) is an orally administered drug for the treatment of metastatic breast cancer. For expanding its therapeutic horizon, we have prepared its nanocrystals (LPT-NCs) that were subsequently coated with hyaluronic acid (HA) to produce LPT-HA-NCs. The detailed in-vitro and in-vivo investigation of LPT-HA-NCs showed the superior anticancer activity due to active targeting to CD44 receptors than the counterparts LPT-NCs and free LPT. In the triple negative 4T1 cells induced breast tumor bearing female Balb/C mice; LPT-HA-NCs treatment caused significant retardation of tumor growth and overall increase in animal survival probability because of their higher tumor localization, increased residence time. Our findings clearly suggest that HA coated LPT-NCs formulation enhances the activity of LPT against triple negative breast cancer. It exhibited magnificent therapeutic outcome at low dose thus presenting a strategy to reduce dose administrations and minimize dose related toxicity.

Physicochemical Characterization and Cyclodextrin Complexation of the Anticancer Drug Lapatinib

Lapatinib (LAP), the tyrosine kinase inhibitor drug with moderate bioavailability, was characterized in terms of physicochemical properties: acid-base characteristics, lipophilicity, and solubility. The highly lipophilic nature of the drug and its extremely low water solubility (S0=0.82 nM) limit the development of a parenteral formulation. In order to enhance solubility and bioavailability, inclusion complex formation with cyclodextrins (CDs) is a promising method of choice. Therefore, LAP-CD interactions were also studied by a multianalytical approach. The stability constants of LAP with native cyclodextrins, determined by UV spectroscopy, identified the seven-membered β-CD as the most suitable host. Continuous variation method (Job’s plot) by 1H NMR showed a 1 : 1 stoichiometry for the complexes. The geometry of the complex was elucidated by 2D ROESY NMR measurements and molecular modeling, indicating that the partial molecular encapsulation includes the fluorophenyl ring of LAP. Phase-solubility studies with four CDs, β-CD, (2-hydroxypropyl)-β-cyclodextrin (HP-β-CD), randomly methylated-β- (RAMEB-) cyclodextrin, and sulfobutylether-β-cyclodextrin (SBE-β-CD), show an AL type diagram and highly increased solubility via CD complexation. The results are especially promising with SBE-β-CD, exerting more than 600-fold gain in solubility. The equilibrium and structural information presented herein can offer the molecular basis for an improved drug formulation with enhanced bioavailability.

Pharmacokinetic Properties of Anticancer Agents for the Treatment of Central Nervous System Tumors: Update of the Literature

Despite significant improvement in outcomes for patients with hematologic malignancies and solid tumors over the past 10 years, patients with primary or metastatic brain tumors continue to have a poor prognosis. A primary reason for this is the inability of many chemotherapeutic drugs to penetrate into the brain and brain tumors at concentrations high enough to exert an antitumor effect because of unique barriers and efflux transporters. Several studies have been published recently examining the central nervous system pharmacokinetics of various anticancer drugs in patients with primary and metastatic brain tumors. To summarize recent advances in the field, this review critically presents studies published within the last 9 years examining brain and cerebrospinal fluid penetration of clinically available anticancer agents for patients with central nervous system tumors.

Lapatinib Plasma and Tumor Concentrations and Effects on HER Receptor Phosphorylation in Tumor

PURPOSE

The paradigm shift in cancer treatment from cytotoxic drugs to tumor targeted therapies poses new challenges, including optimization of dose and schedule based on a biologically effective dose, rather than the historical maximum tolerated dose. Optimal dosing is currently determined using concentrations of tyrosine kinase inhibitors in plasma as a surrogate for tumor concentrations. To examine this plasma-tumor relationship, we explored the association between lapatinib levels in tumor and plasma in mice and humans, and those effects on phosphorylation of human epidermal growth factor receptors (HER) in human tumors.

EXPERIMENTAL DESIGN

Mice bearing BT474 HER2+ human breast cancer xenografts were dosed once or twice daily (BID) with lapatinib. Drug concentrations were measured in blood, tumor, liver, and kidney. In a randomized phase I clinical trial, 28 treatment-naïve female patients with early stage HER2+ breast cancer received lapatinib 1000 or 1500 mg once daily (QD) or 500 mg BID before evaluating steady-state lapatinib levels in plasma and tumor.

RESULTS

In mice, lapatinib levels were 4-fold higher in tumor than blood with a 4-fold longer half-life. Tumor concentrations exceeded the in vitro IC90 (~ 900 nM or 500 ng/mL) for inhibition of HER2 phosphorylation throughout the 12-hour dosing interval. In patients, tumor levels were 6- and 10-fold higher with QD and BID dosing, respectively, compared to plasma trough levels. The relationship between tumor and plasma concentration was complex, indicating multiple determinants. HER receptor phosphorylation varied depending upon lapatinib tumor concentrations, suggestive of changes in the repertoire of HER homo- and heterodimers.

CONCLUSION

Plasma lapatinib concentrations underestimated tumor drug levels, suggesting that optimal dosing should be focused on the site of action to avoid to inappropriate dose escalation. Larger clinical trials are required to determine optimal dose and schedule to achieve tumor concentrations that maximally inhibit HER receptors.

TRIAL REGISTRATION

CLINICAL TRIAL REGISTRATION

NCT00359190.

Management of pulmonary toxicity associated with targeted anticancer therapies

INTRODUCTION

Targeted anticancer therapies act by interfering with defined molecular entities and/or biologic pathways. Because of their more specific mechanism of action, adverse events (AEs) on healthy tissues are intended to be minimal, resulting in a different toxicity profile from that observed with conventional cytotoxic chemotherapy. Pulmonary AEs are rare but potentially life-threatening and it is, therefore, critical to recognize early on and manage appropriately.

AREAS COVERED

In this review, we aim to offer an overview of both more frequent and rare pulmonary AEs caused by targeted anticancer therapies and discuss possible treatment algorithms. Anti-vascular endothelial growth factor, anti-human epidermal growth factor receptor and anti-CD20 therapy will be reviewed, as well as immune checkpoint inhibitors, anaplastic lymphoma kinase inhibitors and mammalian target of rapamycin inhibitors.

EXPERT OPINION

Novel agents used in the treatment of cancer have specific side-effects, the result of allergic reactions, on-target and off-target effects. Clinical syndromes associated with pulmonary toxicity vary from bronchospasms, hypersensitivity reactions, pneumonitis, acute respiratory distress, lung bleeding, pleural effusion to pneumothorax. Knowledge of risk factors, a high index of suspicion and a complete diagnostic work-up are essential for limiting the risk of these events becoming life threatening. The development of treatment algorithms is extremely helpful in managing these events. It is probable that these toxicities will be even more frequent with the introduction of combination therapies with the obvious challenge of discerning the responsible agent.

Novel nanosystem to enhance the antitumor activity of lapatinib in breast cancer treatment: Therapeutic efficacy evaluation

The present study was performed to investigate the therapeutic performance of polymer-lipid hybrid nanoparticles towards the delivery of lapatinib (LPT) in breast cancers. We have successfully developed the lapatinib-loaded polymer-lipid hybrid nanosystem and showed its therapeutic potential in in vitro and in vivo models of breast cancer. The nanoformulations consisted of a polymeric core (poly[lactide-co-glycolide]-D-a-tocopheryl polyethylene glycol 1000 succinate [PLGA-TPGS]), which was then enveloped by a PEGylated lipid layer (DSPE-PEG) (PLPT) to maintain the structural integrity. The PLPT formulation controlled the drug release in pH 7.4 conditions and accelerated the release at pH 5.5 conditions. The PLPT showed a remarkable cellular internalization and efficiently killed the MCF-7 cancer cells in a time- and concentration-dependent manner. Moreover, LPT-loaded nanoparticles effectively induced apoptosis of cancer cells than compared to free LPT. Pharmacokinetic data suggested that nanoparticles could significantly enhance the blood circulation time of LPT by reducing the uptake by a reticuloendothelial system (RES). The prolonged blood circulation of PLPT could allow the preferential accumulation of drug in the tumor tissues. Importantly, PLPT significantly reduced the tumor burden of cancerous mice and effectively controlled the tumor cell proliferation. TUNEL assay further showed a greater apoptosis of tumor tissues in the PLPT treated mice group. Our results suggest that the use of a hybrid system may allow a decrease in the dosage regimen without the loss of therapeutic effect. Overall, lapatinib-loaded hybrid nanoparticles hold great potential for achieving an optimal therapeutic effect in breast cancer treatment. The present anticancer drug delivery system could be potentially applied for the treatment of other cancers.

The potential use of lapatinib-loaded human serum albumin nanoparticles in the treatment of triple-negative breast cancer

Triple-negative breast cancer (TNBC) is an aggressive cancer with limited treatment options. However, the shared feature of epidermal growth factor receptor (EGFR) expression in TNBC offers the opportunity for targeted molecular therapy for this breast cancer subtype. Previous studies have indicated that lapatinib, a selective small-molecular dual-tyrosine kinase inhibitor of HER2 and EGFR, is effective in reducing cancer progression and metastasis, indicating that it might be a candidate for TNBC treatment. However, its poor water solubility, low and variable oral absorption, and large daily dose all limit the clinical use of lapatinib. In this study, we developed human serum albumin (HSA) nanoparticles loaded with lapatinib for intravenous administration to overcome these disadvantages and enhance its efficacy against TNBC. 4T1 cells (a murine TNBC cells) were selected as the cell model because their growth and metastatic spread are very close to those of human breast cancer cells. Lapatinib-loaded HSA nanoparticles (LHNPs) were prepared by Nab technology. LHNPs displayed cytotoxicity similar to the free drug but exhibited superior capacity to induce early apoptosis in 4T1 monolayer cells. Importantly, LHNPs showed improved penetration and inhibition effects in tumor spheroids compared to lapatinib solution (LS). Pharmacokinetic investigations revealed that HSA nanoparticles (i.v.) effectively increased the accumulation of lapatinib in tumor tissue at 2.38 and 16.6 times the level of LS (i.v.) and Tykerb (p.o.), respectively. Consequently, it had markedly better suppression effects both on primary breast cancer and lung metastasis in tumor-bearing mice compared to the commercial drug Tykerb. The improved anti-tumor efficacy of LHNPs may be partly attributed to its close binding to SPARC, which is widely present in the extracellular matrix of tumor tissue. These results demonstrated that LHNPs might be a promising anti-tumor agent for TNBC.

A phase I pharmacokinetics study of lapatinib and tamoxifen in metastatic breast cancer (EORTC 10053 Lapatam study)

OBJECTIVE

This phase I study assessed the pharmacokinetic (PK), tolerability, safety and preliminary clinical activity of tamoxifen (T) and lapatinib (L) in patients with metastatic breast cancer (MBC).

METHODS

Patients (pts) with hormone receptor positive MBC, irrespective of HER-2 status, were randomly assigned to T → T + L group, tamoxifen in cycle 1 for 28 days then adding lapatinib on day 1 of cycle 2; or L → T + L group, lapatinib in cycle 1 for 14 days, then adding tamoxifen on day 1 of cycle 2 to evaluate the potential drug-drug PK interaction at steady-state. The dose of tamoxifen was 20 mg/day and lapatinib 1500 mg/day.

RESULTS

Twenty-five pts were enrolled of which 23 started treatment, five (22%) of them were HER-2 positive. Median age was 59 years and 96% had PS ≤1. Eleven (91.7%) pts in the T → T + L group and 10 (76.9%) in L → T + L group received at least 2 cycles of treatment. The most frequently reported drug-related adverse events (>25% of patients) were diarrhoea (62%), anaemia (56%), rash (52%), fatigue (52%), dermatology other (34%) and leukopenia (28%). Grade 3-4 drug-related toxicities were infrequent (<10%). No cardiotoxicity was observed. T plasma concentrations did not appeared to be affected by the presence of lapatinib. L steady-state plasma concentrations were 20% lower after 28 days of co-administration with T. Eight (36.4%) patients experienced stable disease and median progression free survival was 2.7 months.

CONCLUSIONS

The combination of L and T was safe and clinically active. T affected L plasma concentrations, which remained within the therapeutic index.

Capecitabine and lapatinib uptake in surgically resected brain metastases from metastatic breast cancer patients: a prospective study

BACKGROUND

Breast cancer brain metastases (BCBM) are challenging complications that respond poorly to systemic therapy. The role of the blood-tumor barrier in limiting BCBM drug delivery and efficacy has been debated. Herein, we determined tissue and serum levels of capecitabine, its prodrug metabolites, and lapatinib in women with BCBM resected via medically indicated craniotomy.

METHODS

Study patients with BCBM requiring surgical resection received either single-dose capecitabine (1250 mg/m(2)) 2-3 h before surgery or 2-5 doses of lapatinib (1250 mg) daily, the last dose 2-3 h before surgery. Serum samples were collected serially on the day of surgery. Drug concentrations were determined in serum and BCBM using liquid chromatography tandem mass spectrometry.

RESULTS

Twelve patients were enrolled: 8 for capecitabine and 4 for lapatinib. Measurable drug levels of capecitabine and metabolites, 5'-deoxy-5-fluorocytidine, 5'-deoxy-5-fluorouridine, and 5-fluorouracil, were detected in all BCBM. The ratio of BCBM to serum was higher for 5-fluorouracil than for capecitabine. As for lapatinib, the median BCBM concentrations ranged from 1.0 to 6.5 µM. A high variability (0.19-9.8) was noted for lapatinib BCBM-to-serum ratio.

CONCLUSIONS

This is the first study to demonstrate that capecitabine and lapatinib penetrate to a significant though variable degree in human BCBM. Drug delivery to BCBM is variable and in many cases appears partially limiting. Elucidating mechanisms that limit drug concentration and innovative approaches to overcome limited drug uptake will be important to improve clinical efficacy of these agents in the central nervous system. Trial registration ID: NCT00795678.

Development of the rat model of lapatinib-induced diarrhoea

Targeted therapy of cancer is often associated with clinically significant diarrhoea; however, the mechanisms underpinning this adverse effect are currently unknown. Diarrhoea following treatment with tyrosine kinase inhibitors (TKIs) of EGFR is particularly troublesome. Until recently, understanding of EGFR TKI-induced diarrhoea has been limited to clinical observation. However, our group has recently developed the first rat model of EGFR TKI-induced diarrhoea. This paper reviews the published and unpublished findings.

Pharmacokinetic interaction of entinostat and lapatinib following single and co-oral administration in rats

1. Entinostat, also known as SNDX-275 or MS-275, is a novel, potent, orally bioavailable, class I selective histone deacetylase inhibitor. Pre-clinical data has show that MS-275 can enhance the activity of lapatinib in HER(2+) metastatic inflammatory and non-inflammatory breast cancer. This study examined whether oral administration of MS-275 to the rats with lapatinib led to any pharmacokinetic interactions. 2. To evaluate pharmacokinetic interaction of MS-275 and lapatinib in rat, a sensitive and simple LC-MS method was developed to simultaneously determine MS-275 and lapatinib in rat plasma with carbamazepine as internal standard (IS). Eighteen rats were divided randomly into three groups, lapatinib group (lapatinib 15 mg/kg, n = 8), MS-275 group (MS-275 15 mg/kg, n = 8) and co-administration group (MS-275 15 mg/kg and lapatinib 15 mg/kg, n = 8). 3. There was no statistical pharmacokinetics difference for MS-275 in MS-275 group and co-administration group; the lapatinib could not influence the pharmacokinetic profile of MS-275 in rats. However, there is a statistical pharmacokinetics difference between lapatinib in the lapatinib group and co-administration group, when co-oral administration MS-275 with lapatinib, AUC increased from 2375.5 to 9900.3 ng/mL h (p < 0.05), Cmax increased from 538.0 to 2578.2 ng/mL (p < 0.01), CL decreased from 6.2 to 1.7 L/h/kg (p < 0.01). 4. These data indicate MS-275 could obviously influence the pharmacokinetic profile of lapatinib in rats, which might cause drug-drug interactions in humans when using lapatinib with MS-275. Further investigations should be carried out to elucidate the synergistic mechanisms between the two drugs.

Chemotherapy and QT Prolongation: Overview With Clinical Perspective

OPINION STATEMENT

Cardiotoxic adverse events are of concern to physicians treating cancer patients; they are encountered with a variety of agents. Cardiac events may delay the approval of new drugs or impose burdensome monitoring requirements as either part of the pre-approval process or in the daily use of these agents. Among the cardiac issues are the development of QT prolongation and the fear of torsades de pointes (TdP), an unusual yet potentially fatal form of ventricular tachycardia associated with QT prolongation. Several risk factors, including electrolyte imbalance and polypharmacy with concomitant QT prolonging agents use can increase the risk of TdP in cancer patients; separating the individual contributions of the various triggers for TdP remains problematic. Understanding the individual risk of QT prolongation associated with particular chemotherapies can better differentiate between those shown to have higher risk vs. those with lower risk potential. Cardiac monitoring and electrocardiogram analysis require recognition of the common challenges with regard to the precise measurement of the QT interval such as the presence of U waves, intraventricular conduction delays, and heart rate correction. Rapid identification and treatment of QT prolongation and TdP is critical in mitigating the risk of sudden cardiac death in cancer patients. A multidisciplinary treatment approach among cardiologists and oncologists should be employed to help facilitate an appropriate balance between oncologic efficacy and adverse cardiac events.

Clinical pharmacokinetics of tyrosine kinase inhibitors: implications for therapeutic drug monitoring

The treatment of many malignancies has been improved in recent years by the introduction of molecular targeted therapies. These drugs interact preferentially with specific targets that are mutated and/or overexpressed in malignant cells. A group of such targets are the tyrosine kinases, against which a number of inhibitors (tyrosine kinase inhibitors, TKIs) have been developed. Imatinib, a TKI with targets that include the breakpoint cluster region-Abelson (bcr-abl) fusion protein kinase and mast/stem cell growth factor receptor kinase (c-Kit), was the first clinically successful drug of this type and revolutionized the treatment and prognosis of chronic myeloid leukemia and gastrointestinal stromal tumors. This success paved the way for the development of other TKIs for the treatment of a range of hematological malignancies and solid tumors. To date, 14 TKIs have been approved for clinical use and many more are under investigation. All these agents are given orally and are substrates of a range of drug transporters and metabolizing enzymes. In addition, some TKIs are capable of inhibiting their own transporters and metabolizing enzymes, making their disposition and metabolism at steady-state unpredictable. A given dose can therefore give rise to markedly different plasma concentrations in different patients, favoring the selection of resistant clones in the case of subtherapeutic exposure, and increasing the risk of toxicity if dosage is excessive. The aim of this review was to summarize current knowledge of the clinical pharmacokinetics and known adverse effects of the TKIs that are available for clinical use and to provide practical guidance on the implications of these data in patient management, in particular with respect to therapeutic drug monitoring.

Phase I dose-escalation study of 5-day intermittent oral lapatinib therapy in patients with human epidermal growth factor receptor 2-overexpressing breast cancer

PURPOSE

The highly effective treatment of human epidermal growth factor receptor (HER) 2-amplified breast cancer has proven challenging because of a signal buffering capacity inherent in the functionally relevant HER2-HER3 target. HER2-HER3 signaling can be inactivated by doses of lapatinib that fully inactivate the HER2 kinase. In mouse models, such doses are not tolerable in continuous administration, but they are tolerable and highly effective in intermittent dosing. We pursued the clinical translation of this treatment hypothesis.

PATIENTS AND METHODS

We conducted a phase I dose-escalation study in women with advanced HER2-overexpressing breast cancer. Lapatinib was administered on days 1 through 5 of repeating 14-day cycles. Dose escalation was conducted using a 3+3 design with plasma lapatinib level monitoring.

RESULTS

Forty patients were evaluable for toxicity, and 34 patients were evaluable for dose-limiting toxicity (DLT). Lapatinib dose was escalated to 7,000 mg per day in twice-daily dosing with no DLTs; however, plasma lapatinib concentrations plateaued in this dose range. Additional cohorts evaluated strategies to increase lapatinib exposure, including the food effect, CYP3A4 inhibition, and dose fractionation. Of these, only ketoconazole was able to increase lapatinib exposure, despite highly variable lapatinib bioavailability. Intolerable exposure levels were not encountered. Eight patients (20%) experienced grade 3 diarrhea. Six patients achieved a response, and dramatic responses were seen in three patients with lapatinib concentrations approaching 10,000 ng/mL.

CONCLUSION

Lapatinib exposure can be safely and significantly increased through intermittent dosing but reaches a ceiling that currently impedes clinical translation of the treatment hypothesis. Preliminary efficacy data suggest that exposures approaching those seen in mouse models can result in highly significant tumor responses.