Estimating healthcare resource use associated with the treatment of metastatic melanoma in eight countries.

Objectives Studies reporting healthcare resourse use (HRU) for melanoma, one of the most costly cancers to treat, are limited. Using consistent, robust methodology, this study estimated HRU associated with the treatment of metastatic melanoma in eight countries. Methods Using published literature and clinician input, treatment phases were identified: active systemic treatment (pre-progression); disease progression; best supportive care (BSC)/palliative care; and terminal care. HRU elements were identified for each phase and estimates of the magnitude and frequency of use in clinical practice were obtained through country-specific Delphi panels, comprising healthcare professionals with experience in oncology (n = 8). Results Medical oncologists are the key care providers for patients with metastatic melanoma, although in Germany dermato-oncologists also lead care. During the active systemic treatment phase, each patient was estimated to require 0.83-2 consultations with a medical oncologist/month across countries; the median number of such assessments in 3 months was highest in Canada (range = 3.5-5) and lowest in France, the Netherlands and Spain (1). Resource use during the disease progression phase was intensive and similar across countries: all patients were estimated to consult with medical oncologists and 10-40% with a radiation oncologist; up to 40% were estimated to require a brain MRI scan. During the BSC/palliative care phase, all patients were estimated to consult with medical oncologists, and most to consult with a primary care physician (40-100%). Limitations Panelists were from centers of excellence, thus results may not reflect care within smaller hospitals; data obtained from experts may be less variable than data from broader clinical practice. Treatments for metastatic melanoma are continually emerging, thus some elements of our work could be superseded. Conclusions HRU estimates were substantial and varied across countries for some resources. These data could be used with country-specific costs to elucidate costs for the management of metastatic melanoma.

Population preference values for health states in relapsed or refractory B-precursor acute lymphoblastic leukemia in the United Kingdom.

BACKGROUND: To date, reliable and comprehensive health-related quality of life data for patients with relapsed or refractory B-precursor acute lymphoblastic leukemia (ALL) have not been collected in clinical trials of the disease, and no utility studies have been published. The purpose of this study was to define and validate health states experienced by adults with relapsed/refractory B-precursor ALL, and to assign utility values to these health states using time-trade off methodology. METHODS: This study was conducted in the UK in three phases. In the first phase, five health state descriptions were developed based on a recent clinical trial. The second phase validated the health state descriptions with clinicians and patients with experience of relapsed/refractory B-precursor ALL. The third phase involved prospective health state valuation using time-trade off methodology in a sample of the general public. The study was approved by the UK National Health Service Research Ethics Committee. RESULTS: In total, 123 participants were recruited and included in the final analysis; all participants gave written, informed consent. Complete remission was the most preferred health state (mean utility [SEM], 0.86 [0.01]), followed by complete remission with partial hematological recovery (with minimal risk of bleeding or developing infection) (0.75 [0.02]); aplastic bone marrow (0.59 [0.02]); partial remission (0.50 [0.03]); and progressive disease (0.30 [0.04]). CONCLUSIONS: This is the first study to report utility values for health states associated with relapsed/refractory B-precursor ALL. It was designed and conducted to align with NICE guidance on alternative methods for generating health state utility values when EQ-5D data are either unavailable or inappropriate. These utilities can be applied in future cost-effectiveness analyses of treatment for relapsed/refractory B-precursor ALL.

Nuclear HER4 mediates acquired resistance to trastuzumab and is associated with poor outcome in HER2 positive breast cancer.

The role of HER4 in breast cancer is controversial and its role in relation to trastuzumab resistance remains unclear. We showed that trastuzumab treatment and its acquired resistance induced HER4 upregulation, cleavage and nuclear translocation. However, knockdown of HER4 by specific siRNAs increased trastuzumab sensitivity and reversed its resistance in HER2 positive breast cancer cells. Preventing HER4 cleavage by a γ-secretase inhibitor and inhibiting HER4 tyrosine kinase activity by neratinib decreased trastuzumab-induced HER4 nuclear translocation and enhanced trastuzumab response. There was also increased nuclear HER4 staining in the tumours from BT474 xenograft mice and human patients treated with trastuzumab. Furthermore, nuclear HER4 predicted poor clinical response to trastuzumab monotherapy in patients undergoing a window study and was shown to be an independent poor prognostic factor in HER2 positive breast cancer. Our data suggest that HER4 plays a key role in relation to trastuzumab resistance in HER2 positive breast cancer. Therefore, our study provides novel findings that HER4 activation, cleavage and nuclear translocation influence trastuzumab sensitivity and resistance in HER2 positive breast cancer. Nuclear HER4 could be a potential prognostic and predictive biomarker and understanding the role of HER4 may provide strategies to overcome trastuzumab resistance in HER2 positive breast cancer.

ADAM10 mediates trastuzumab resistance and is correlated with survival in HER2 positive breast cancer.

Trastuzumab prolongs survival in HER2 positive breast cancer patients. However, resistance remains a challenge. We have previously shown that ADAM17 plays a key role in maintaining HER2 phosphorylation during trastuzumab treatment. Beside ADAM17, ADAM10 is the other well characterized ADAM protease responsible for HER ligand shedding. Therefore, we studied the role of ADAM10 in relation to trastuzumab treatment and resistance in HER2 positive breast cancer. ADAM10 expression was assessed in HER2 positive breast cancer cell lines and xenograft mice treated with trastuzumab. Trastuzumab treatment increased ADAM10 levels in HER2 positive breast cancer cells (p ≤ 0.001 in BT474; p ≤ 0.01 in SKBR3) and in vivo (p ≤ 0.0001) compared to control, correlating with a decrease in PKB phosphorylation. ADAM10 inhibition or knockdown enhanced trastuzumab response in naïve and trastuzumab resistant breast cancer cells. Trastuzumab monotherapy upregulated ADAM10 (p ≤ 0.05); and higher pre-treatment ADAM10 levels correlated with decreased clinical response (p ≤ 0.05) at day 21 in HER2 positive breast cancer patients undergoing a trastuzumab treatment window study. Higher ADAM10 levels correlated with poorer relapse-free survival (p ≤ 0.01) in a cohort of HER2 positive breast cancer patients. Our studies implicate a role of ADAM10 in acquired resistance to trastuzumab and establish ADAM10 as a therapeutic target and a potential biomarker for HER2 positive breast cancer patients.

Neratinib overcomes trastuzumab resistance in HER2 amplified breast cancer.

Trastuzumab has been shown to improve the survival outcomes of HER2 positive breast cancer patients. However, a significant proportion of HER2-positive patients are either inherently resistant or develop resistance to trastuzumab. We assessed the effects of neratinib, an irreversible panHER inhibitor, in a panel of 36 breast cancer cell lines. We further assessed its effects with or without trastuzumab in several sensitive and resistant breast cancer cells as well as a BT474 xenograft model. We confirmed that neratinib was significantly more active in HER2-amplified than HER2 non-amplified cell lines. Neratinib decreased the activation of the 4 HER receptors and inhibited downstream pathways. However, HER3 and Akt were reactivated at 24 hours, which was prevented by the combination of trastuzumab and neratinib. Neratinib also decreased pHER2 and pHER3 in acquired trastuzumab resistant cells. Neratinib in combination with trastuzumab had a greater growth inhibitory effect than either drug alone in 4 HER2 positive cell lines. Furthermore, trastuzumab in combination with neratinib was growth inhibitory in SKBR3 and BT474 cells which had acquired resistance to trastuzumab as well as in a BT474 xenograft model. Innately trastuzumab resistant cell lines showed sensitivity to neratinib, but the combination did not enhance response compared to neratinib alone. Levels of HER2 and phospho-HER2 showed a direct correlation with sensitivity to neratinib. Our data indicate that neratinib is an effective anti-HER2 therapy and counteracted both innate and acquired trastuzumab resistance in HER2 positive breast cancer. Our results suggest that combined treatment with trastuzumab and neratinib is likely to be more effective than either treatment alone for both trastuzumab-sensitive breast cancer as well as HER2-positive tumors with acquired resistance to trastuzumab.

Ubiquitination by the membrane-associated RING-CH-8 (MARCH-8) ligase controls steady-state cell surface expression of tumor necrosis factor-related apoptosis inducing ligand (TRAIL) receptor 1.

The eleven members of the membrane-associated RING-CH (MARCH) ubiquitin ligase family are relatively unexplored. Upon exogenous (over)expression, a number of these ligases can affect the trafficking of membrane molecules. However, only for MARCH-1 endogenous functions have been demonstrated. For the other endogenous MARCH proteins, no functions or substrates are known. We report here that TRAIL-R1 is a physiological substrate of the endogenous MARCH-8 ligase. Human TRAIL-R1 and R2 play a role in immunosurveillance and are targets for cancer therapy, because they selectively induce apoptosis in tumor cells. We demonstrate that TRAIL-R1 is down-regulated from the cell surface, with great preference over TRAIL-R2, by exogenous expression of MARCH ligases that are implicated in endosomal trafficking, such as MARCH-1 and -8. MARCH-8 attenuated TRAIL-R1 cell surface expression and apoptosis signaling by virtue of its ligase activity. This suggested that ubiquitination of TRAIL-R1 was instrumental in its down-regulation by MARCH-8. Indeed, in cells with endogenous MARCH expression, TRAIL-R1 was ubiquitinated at steady-state, with the conserved membrane-proximal lysine 273 as one of the potential acceptor sites. This residue was also essential for the interaction of TRAIL-R1 with MARCH-1 and MARCH-8 and its down-regulation by these ligases. Gene silencing identified MARCH-8 as the endogenous ligase that ubiquitinates TRAIL-R1 and attenuates its cell surface expression. These findings reveal that endogenous MARCH-8 regulates the steady-state cell surface expression of TRAIL-R1.

Potential of PET to predict the response to trastuzumab treatment in an ErbB2-positive human xenograft tumor model.

UNLABELLED: Currently, an alteration in the gross volume of a tumor is used to assess its response to trastuzumab; however, this approach provides only a late indication of response. Tissue-sample ex vivo assays are potentially valuable, but their procurement through biopsies is invasive and might be biased by tumor heterogeneity. We studied the feasibility of using PET to quantify changes in ErbB2 (HER2/neu) expression and to predict the response to trastuzumab in BT474 breast cancer xenografts with N-[2-(4-(18)F-fluorobenzamido)ethyl]maleimide ((18)F-FBEM)-HER(2:342) Affibody. METHODS: Mice bearing BT474 tumors were given trastuzumab (50 mg/kg loading dose, 25 mg/kg maintenance dose, administered intraperitoneally twice a week) or saline (control) for a total of 5 doses. Tumor size was monitored twice a week. Animals were scanned before the treatment, at 48 h, and 2 wk after the beginning of therapy. After the final scan, PET results were correlated with tumor response and immunohistochemical assessment of ErbB2 level, as well as with vasculature in the treated tumors. RESULTS: Analysis of PET images indicated that tracer uptake was significantly reduced after 1 dose of trastuzumab, compared with baseline, suggesting applicability as an early indicator of changes in ErbB2 expression. After 5 doses of trastuzumab, the overall decrease in (18)F-FBEM-HER(2:342) Affibody uptake also correlated with tumor response and downregulation of ErbB2 expression by immunohistochemical assessment. However, individual animals had different responses. There was a correlation between bigger PET changes and a higher vessel count in the tumors, suggesting that an increased number of vessels could lead to better trastuzumab delivery. We confirmed that the difference in average vessel count in the tumors was not related to the size of the tumors and therefore was not due to the selection of more vascular tumors. This finding is consistent with previous findings demonstrating that the number of vessels in a tumor could be a useful prognostic marker for treatment response. CONCLUSION: Our data suggest that Affibody-based PET can noninvasively provide specific information on changes in receptor expression and could be a valuable strategy for predicting tumor response to trastuzumab.

Assessment of EGFR/HER2 dimerization by FRET-FLIM utilizing Alexa-conjugated secondary antibodies in relation to targeted therapies in cancers.

The expression level of the HER family is unreliable as a predictive marker for targeted therapies in cancer. Thus, there is a need to develop other biomarkers, which can be used to accurately select responsive patients for targeted therapies. The HER dimerization status may be more important than HER receptor expression per se in determining sensitivity or resistance to a given therapeutic agent. The aim of the study is to develop a FRET assay using dye conjugated secondary antibodies to assess HER receptor dimerization. Using primary antibodies from different species in conjunction with Alexa488 and Alexa546 conjugated secondary antibodies, we validated our EGFR/HER2 dimerization assay in three cell lines, EGFR positive A431 cells as well as HER2 positive breast cell lines BT474 and SKBR3 cells. Finally, we applied our assay to assess EGFR/HER2 dimerization in paraffin embedded cell pellets. Our results show promise for the assay to be applied to tumor samples in order to assess the prognostic significance and predictive value of HER receptor dimerization in various cancers.

HER2 phosphorylation is maintained by a PKB negative feedback loop in response to anti-HER2 herceptin in breast cancer.

Herceptin (trastuzumab) is used in patients with breast cancer who have HER2 (ErbB2)-positive tumours. However, its mechanisms of action and how acquired resistance to Herceptin occurs are still poorly understood. It was previously thought that the anti-HER2 monoclonal antibody Herceptin inhibits HER2 signalling, but recent studies have shown that Herceptin does not decrease HER2 phosphorylation. Its failure to abolish HER2 phosphorylation may be a key to why acquired resistance inevitably occurs for all responders if Herceptin is given as monotherapy. To date, no studies have explained why Herceptin does not abolish HER2 phosphorylation. The objective of this study was to investigate why Herceptin did not decrease HER2 phosphorylation despite being an anti-HER2 monoclonal antibody. We also investigated the effects of acute and chronic Herceptin treatment on HER3 and PKB phosphorylation in HER2-positive breast cancer cells. Using both Förster resonance energy transfer (FRET) methodology and conventional Western blot, we have found the molecular mechanisms whereby Herceptin fails to abolish HER2 phosphorylation. HER2 phosphorylation is maintained by ligand-mediated activation of EGFR, HER3, and HER4 receptors, resulting in their dimerisation with HER2. The release of HER ligands was mediated by ADAM17 through a PKB negative feedback loop. The feedback loop was activated because of the inhibition of PKB by Herceptin treatment since up-regulation of HER ligands and ADAM17 also occurred when PKB phosphorylation was inhibited by a PKB inhibitor (Akt inhibitor VIII, Akti-1/2). The combination of Herceptin with ADAM17 inhibitors or the panHER inhibitor JNJ-26483327 was able to abrogate the feedback loop and decrease HER2 phosphorylation. Furthermore, the combination of Herceptin with JNJ-26483327 was synergistic in tumour inhibition in a BT474 xenograft model. We have determined that a PKB negative feedback loop links ADAM17 and HER ligands in maintaining HER2 phosphorylation during Herceptin treatment. The activation of other HER receptors via ADAM17 may mediate acquired resistance to Herceptin in HER2-overexpressing breast cancer. This finding offers treatment opportunities for overcoming resistance in these patients. We propose that Herceptin should be combined with a panHER inhibitor or an ADAM inhibitor to overcome the acquired drug resistance for patients with HER2-positive breast cancer. Our results may also have implications for resistance to other therapies targeting HER receptors.