Population Pharmacokinetics of Liposomal Irinotecan in Patients With Cancer

Nanoliposomal irinotecan (nal‐IRI) is a liposomal formulation of irinotecan with a longer half‐life (t_1/2), higher plasma total irinotecan (tIRI), and lower SN‐38 maximum concentration (C_max) compared with nonliposomal irinotecan. Population pharmacokinetic (PK) analysis of nal‐IRI was performed for tIRI and total SN‐38 (tSN38) using patient samples from six studies. PK‐safety association was evaluated for neutropenia and diarrhea in 353 patients. PK‐efficacy association was evaluated from a phase III study in pancreatic cancer NAPOLI1. Efficacy was associated with longer duration of unencapsulated SN‐38 (uSN38) above a threshold and higher C_avg of tIRI, tSN38, and uSN38. Neutropenia was associated with uSN38 C_max and diarrhea with tIRI C_max. Baseline predictive factors were race, body surface area, and bilirubin. Analysis identified PK factors associated with efficacy, safety, and predictive baseline factors. The results support the benefit of nal‐IRI dose of 70 mg/m² (free‐base; equivalent to 80 mg/m² salt base) Q2W over 100 mg/m² Q3W.

Evaluation of a semi-automated software program for the identification of vertebral fractures in children

AIM

To assess observer reliability and diagnostic accuracy in children, of a semi-automated six-point technique developed for vertebral fracture (VF) diagnosis in adults, which records percentage loss of vertebral body height.

MATERIALS AND METHODS

Using a semi-automated software program, five observers independently assessed T4 to L4 from the lateral spine radiographs of 137 children and adolescents for VF. A previous consensus read by three paediatric radiologists using a simplified algorithm-based qualitative technique (i.e., no software involved) served as the reference standard.

RESULTS

Of a total of 1,781 vertebrae, 1,187 (67%) were adequately visualised according to three or more observers. Interobserver agreement in vertebral readability for each vertebral level for five observers ranged from 0.05 to 0.47 (95% CI: -0.19, 0.76). Intra-observer agreement using the intraclass correlation coefficient (ICC) ranged from 0.25 to 0.61. The overall sensitivity and specificity were 18% (95% CI: 14-22) and 97% (95% CI: 97-98), respectively.

CONCLUSION

In contrast to adults, the six-point technique assessing anterior, middle, and posterior vertebral height ratios is neither satisfactorily reliable nor sensitive for VF diagnosis in children. Training of the software on paediatric images is required in order to develop a paediatric standard that incorporates not only specific vertebral body height ratios but also the age-related physiological changes in vertebral shape that occur throughout childhood.

Abstract P2-05-21: Predictive value of quantitative HER2 and HER3 levels combined with downstream signaling markers in HER2-positive advanced breast cancer patients treated with lapatinib

Background: Clinical correlates of lapatinib resistance have not been well defined. Previous studies implicated genes regulated by the estrogen receptor (ER) and activation or mutation of proteins downstream from HER family receptors. In the current study, HER2 and HER3 expression levels were quantitatively measured using a VeraTag® fluorescence-based assay, in addition to seven downstream signaling proteins determined by IHC. All biomarkers were correlated with overall survival (OS) in patients treated with lapatinib.

Methods: Formalin-fixed, paraffin-embedded samples were obtained from the primary tumor of 191 patients treated with lapatinib plus capecitabine following progression on trastuzumab. The HERmark® Breast Cancer Assay (Monogram Biosciences, South San Francisco) was used to quantify HER2 protein expression levels. HER3 protein expression was quantified using the VeraTag® technology (Monogram Biosciences). Expression of ER, PTEN, Cyclin E, HIF-2alpha, p-p70S6K, p-AMPK and p-MAPK were determined by IHC (Duchnowska et al., Oncotarget 2016; 7:550). OS analyses of HER2 and HER3 were stratified by key clinical variables, including stage and presence of a brain metastasis prior to lapatinib-based therapy.

Results: Among the downstream signaling molecules, HIF-2alpha (r = -0.23; p = 0.047) and ER (r = -0.27; p = 0.005) were negatively correlated with HER2 expression after adjustment for multiple testing. PTEN appeared to correlate with HER3, but was not significant after adjustment for multiple testing. OS was significantly shorter for both those below the cut-off level of positivity by the HERmark assay (HR = 1.8; p = 0.029), and those with above median HER2 levels (HR = 1.7; p = 0.009), as compared to cases with in between levels. The relationship between HER2 and OS is also captured by a U-shaped, parabolic function in HER2 (p = 0.005). Elevated HER3 showed a trend toward a correlation with longer OS (HR = 0.66/log; p = 0.16), somewhat stronger in the ER-negative subset (HR = 0.55/log; p = 0.085) and in the subset with above-median HER2 (0.48/log; p = 0.10), where inhibiting HER2 activation of HER3 may be more important. In multivariate Cox models, HER2 (parabola, intermediate HER2 best, p = 0.001), presence of brain metastases (HR = 2; p < 0.001), ER (HR = 0.60; p = 0.009) and either p-p70S6K (HR = 0.66; p = 0.018) or p-AMPK (HR = 0.67; p = 0.022) were significantly associated with OS (p-p70S6K and p-AMPK were mutually correlated).

Conclusions: Patients with moderately increased HER2 levels may have best outcomes while receiving lapatinib following progression on trastuzumab. This supports recent findings of a less benefit from lapatinib in patients with high HER2 expression (Nunciforo et al., SABCS 2015, P3-07-08). HER3 levels do not seem to substantially impact the prognosis. Further studies are warranted to explore the predictive utility of quantitative HER2 and HER3 in guiding HER2-directed therapies.

Citation Format: Duchnowska R, Sperinde J, Czartoryska-Arlukowicz B, Mysliwiec P, Winslow J, Radecka B, Petropoulos C, Demlova R, Orlikowska M, Kowalczyk A, Lang I, Ziólkowska B, Debska-Szmich S, Merdalska M, Grela-Wojewoda A, Zawrocki A, Biernat W, Huang W, Jassem J. Predictive value of quantitative HER2 and HER3 levels combined with downstream signaling markers in HER2-positive advanced breast cancer patients treated with lapatinib [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P2-05-21.

Hofbauer cells of M2a, M2b and M2c polarization may regulate feto-placental angiogenesis

The human placenta comprises a special type of tissue macrophages, the Hofbauer cells (HBC), which exhibit M2 macrophage phenotype. Several subtypes of M2-polarized macrophages (M2a, M2b and M2c) exist in almost all tissues. Macrophage polarization depends on the way of macrophage activation and leads to the expression of specific cell surface markers and the acquisition of specific functions, including tissue remodeling and the promotion of angiogenesis. The placenta is a highly vascularized and rapidly growing organ, suggesting a role of HBC in feto-placental angiogenesis. We here aimed to characterize the specific polarization and phenotype of HBC and investigated the role of HBC in feto-placental angiogenesis. Therefore, HBC were isolated from third trimester placentas and their phenotype was determined by the presence of cell surface markers (FACS analysis) and secretion of cytokines (ELISA). HBC conditioned medium (CM) was analyzed for pro-angiogenic factors, and the effect of HBC CM on angiogenesis, proliferation and chemoattraction of isolated primary feto-placental endothelial cells (fpEC) was determined in vitro. Our results revealed that isolated HBC possess an M2 polarization, with M2a, M2b and M2c characteristics. HBC secreted the pro-angiogenic molecules VEGF and FGF2. Furthermore, HBC CM stimulated the in vitro angiogenesis of fpEC. However, compared with control medium, chemoattraction of fpEC toward HBC CM was reduced. Proliferation of fpEC was not affected by HBC CM. These findings demonstrate a paracrine regulation of feto-placental angiogenesis by HBC in vitro. Based on our collective results, we propose that the changes in HBC number or phenotype may affect feto-placental angiogenesis.

[Chronic thromboembolic pulmonary hypertension: Recommendations of the Cologne Consensus Conference 2016]

The 2015 European Guidelines on Pulmonary Hypertension did not cover only pulmonary arterial hypertension (PAH), but also other significant subgroups of pulmonary hypertension (PH). In June 2016, a Consensus Conference organized by the PH working groups of the German Society of Cardiology (DGK), the German Society of Respiratory Medicine (DGP) and the German Society of Pediatric Cardiology (DGPK) was held in Cologne, Germany to discuss open and controversial issues surrounding the practical implementation of the European Guidelines. Several working groups were initiated, one of which was dedicated to the diagnosis and treatment of chronic thromboembolic pulmonary hypertension (CTEPH). In every patient with PH of unknown cause CTEPH should be excluded. The primary treatment option is surgical pulmonary endarterectomy (PEA) in a specialized multidisciplinary CTEPH center. Inoperable patients or patients with persistent or recurrent CTEPH after PEA are candidates for targeted drug therapy. For balloon pulmonary angioplasty (BPA), there is currently only limited experience. This option - as PEA - is reserved to specialized centers with expertise for this treatment method. In addition, a brief overview is given on pulmonary artery sarcoma, since its surgical treatment is often analogous to PEA. The recommendations of this working group are summarized in the present paper.

Diagnostic accuracy of DXA compared to conventional spine radiographs for the detection of vertebral fractures in children

OBJECTIVES

In children, radiography is performed to diagnose vertebral fractures and dual energy x-ray absorptiometry (DXA) to assess bone density. In adults, DXA assesses both. We aimed to establish whether DXA can replace spine radiographs in assessment of paediatric vertebral fractures.

METHODS

Prospectively, lateral spine radiographs and lateral spine DXA of 250 children performed on the same day were independently scored by three radiologists using the simplified algorithm-based qualitative technique and blinded to results of the other modality. Consensus radiograph read and second read of 100 random images were performed. Diagnostic accuracy, inter/intraobserver and intermodality agreements, patient/carer experience and radiation dose were assessed.

RESULTS

Average sensitivity and specificity (95 % confidence interval) in diagnosing one or more vertebral fractures requiring treatment was 70 % (58-82 %) and 97 % (94-100 %) respectively for DXA and 74 % (55-93 %) and 96 % (95-98 %) for radiographs. Fleiss' kappa for interobserver and average kappa for intraobserver reliability were 0.371 and 0.631 respectively for DXA and 0.418 and 0.621 for radiographs. Average effective dose was 41.9 μSv for DXA and 232.7 μSv for radiographs. Image quality was similar.

CONCLUSION

Given comparable image quality and non-inferior diagnostic accuracy, lateral spine DXA should replace conventional radiographs for assessment of vertebral fractures in children.

KEY POINTS

• Vertebral fracture diagnostic accuracy of lateral spine DXA is non-inferior to radiographs. • The rate of unreadable vertebrae for DXA is lower than for radiographs. • Effective dose of DXA is significantly lower than radiographs. • Children prefer DXA to radiographs. • Given the above, DXA should replace radiographs for paediatric vertebral fracture assessment.