1stOncology™: Cancer Intelligence Service – Page 16530 – 1stOncology is recognized as a Top 10 Global Pharma Analytic Provider

Therapy response monitoring of the early effects of a new BRAF inhibitor on melanoma xenograft in mice: evaluation of (18) F-FDG-PET and (18) F-FLT-PET.

Inhibition of the V600E mutated BRAF kinase gene (BRAF(V600E) ) is an important and effective approach to treating melanomas. A new specific small molecule inhibitor of BRAF(V600E) , PLX3603, showed potent melanoma growth-inhibiting characteristics in preclinical studies and is currently under clinical investigation. In this study we investigated the feasibility of (18) F-FDG and (18) F-FLT-PET to monitor the early effects of the BRAF(V600E) inhibitor in mice with melanoma xenografts. SCID/beige mice with subcutaneous (s.c.) A375 melanoma xenografts, expressing BRAF(V600E) , received the BRAF(V600E) inhibitor twice daily orally (0, 25, 50 and 75 mg/kg). At 1, 3 and 7 days after start of therapy, the uptake of (18) F-FDG and (18) F-FLT in the tumor and normal tissues was determined in ex vivo tissue samples. Serial (18) F-FDG and (18) F-FLT-PET scans were acquired of animals at 1 day before and 1, 3 and 7 days after start of treatment with 75 mg/kg BRAF(V600E) inhibitor. A dose-dependent decrease in (18) F-FDG uptake in the A375 tumors was observed by ex vivo biodistribution analysis. Administration of 75 mg/kg BRAF inhibitor for 1, 3 and 7 days resulted in a significantly decreased (18) F-FDG uptake in A375 tumors (41, 35 and 51%, respectively). (18) F-FLT uptake in the A375 tumors was low at baseline and no significant changes in (18) F-FLT uptake were observed at any of the doses administered. These effects were corroborated by serial in vivo (18) F-FDG and (18) F-FLT-PET imaging. These data demonstrate that (18) F-FDG-PET can be used as an imaging biomarker to noninvasively evaluate the early effects of PLX3603.
Copyright © 2014 John Wiley &amp; Sons, Ltd.

Schedule your 30 min Free 1stOncology Demo!
Discover why more than 1,500 members use 1stOncology™ to excel in:

Early/Late Stage Pipeline Development - Target Scouting - Clinical Biomarkers - Indication Selection & Expansion - BD&L Contacts - Conference Reports - Combinatorial Drug Settings - Companion Diagnostics - Drug Repositioning - First-in-class Analysis - Competitive Analysis - Deals & Licensing

Schedule Your 30 min Free Demo!

The epigenetic modifier EZH2 controls melanoma growth and metastasis through silencing of distinct tumour suppressors.

Increased activity of the epigenetic modifier EZH2 has been associated with different cancers. However, evidence for a functional role of EZH2 in tumorigenesis in vivo remains poor, in particular in metastasizing solid cancers. Here we reveal central roles of EZH2 in promoting growth and metastasis of cutaneous melanoma. In a melanoma mouse model, conditional Ezh2 ablation as much as treatment with the preclinical EZH2 inhibitor GSK503 stabilizes the disease through inhibition of growth and virtually abolishes metastases formation without affecting normal melanocyte biology. Comparably, in human melanoma cells, EZH2 inactivation impairs proliferation and invasiveness, accompanied by re-expression of tumour suppressors connected to increased patient survival. These EZH2 target genes suppress either melanoma growth or metastasis in vivo, revealing the dual function of EZH2 in promoting tumour progression. Thus, EZH2-mediated epigenetic repression is highly relevant especially during advanced melanoma progression, which makes EZH2 a promising target for novel melanoma therapies.

Pyrexia in dabrafenib-treated melanoma patients is not associated with common genetic variation or HLA polymorphisms.

Pyrexia is a common adverse event (AE) on dabrafenib treatment (monotherapy or combination with trametinib). Since germline SNPs and HLA alleles are implicated in drug-induced AEs, this study investigated their association with pyrexia.
1006 melanoma subjects from five dabrafenib-trametinib clinical studies underwent genotyping for genome-wide SNPs, which enabled imputation of 150 HLA alleles. SNP/HLA allele frequencies were compared between pyrexia cases (n = 218) and controls (n = 361) out of the 1006 subjects by meta-analysis.
This analysis had adequate power to detect association of common SNPs or HLA alleles with moderate to large effects on pyrexia (odds ratio &gt;6), but no significant association was found.
The study suggests that common genetic variation or HLA polymorphisms do not contribute substantially to dabrafenib-induced pyrexia.

PTP1B deficiency enables the ability of a high fat diet to drive the invasive character of PTEN-deficient prostate cancers.

Diet affects the risk and progression of prostate cancer (PCa), but the interplay between diet and genetic alterations in this disease is not understood. Here we present genetic evidence in the mouse showing that PCa progression driven by loss of the tumor suppressor Pten is mainly unresponsive to a high fat diet (HFD), but that coordinate loss of the protein tyrosine phosphatase Ptpn1 (PTP1B in human) enables a highly invasive disease. PCa in Pten-/-Ptpn1-/- mice was characterized by increased cell proliferation and Akt activation, interpreted to reflect a heightened sensitivity to IGF-1 stimulation upon HFD feeding. Prostate-specific overexpression of PTP1B was not sufficient to initiate PCa, arguing that it acted as a diet-dependent modifier of prostate cancer development in Pten-/- mice. Our findings offer a preclinical rationale to investigate the anticancer effects of PTP1B inhibitors currently being studied clinically for diabetes treatment as a new modality for management of prostate cancer.
Copyright ©2016, American Association for Cancer Research (AACR) (Free AACR Whitepaper).

Hepatocellular carcinoma surveillance rates in commercially insured patients with noncirrhotic chronic hepatitis B.

American association for the study of liver diseases (AASLD) and European Association for the Study of the Liver (EASL) guidelines recommend biannual hepatocellular carcinoma (HCC) screening for noncirrhotic patients with chronic hepatitis B infection (HBV), yet there are no data estimating surveillance rates or factors associated with surveillance. We performed a retrospective cohort study of US patients using the Truven Health Analytics databases from 2006 to 2010 and identified patients with noncirrhotic chronic HBV. Surveillance patterns were characterized using categorical and continuous outcomes, with the continuous measure of the proportion of time ‘up to date’ with surveillance (PUTDS), with the 6-month interval following each ultrasound categorized as ‘up to date’. During a median follow-up of 26.0 (IQR: 16.2-40.0) months among 4576 noncirrhotic patients with chronic HBV (median age: 44 years, IQR: 36-52), only 306 (6.7%) had complete surveillance (one ultrasound every 6-month interval), 2727 (59.6%) incomplete (≥1 ultrasound) and 1543 (33.7%) none. The mean PUTDS was 0.34 ± 0.29, and the median was 0.32 (IQR: 0.03-0.52). In multinomial logistic regression models, patients diagnosed by a nongastroenterologist were significantly less likely to have complete surveillance (P &lt; 0.001), as were those coinfected with HBV/HIV (P &lt; 0.001). In linear regression models, nongastroenterologist provider, health insurance subtype, HBV/HIV coinfection, rural status and metabolic syndrome were independently associated with decreased surveillance. Patients with HIV had an absolute decrease in the PUTDS of 0.24, while patients in less populated rural areas had an absolute decrease of 0.10. HCC surveillance rates in noncirrhotic patients with chronic HBV in the United States are poor and lower than reported rates of HCC surveillance in cirrhotic patients.
© 2015 John Wiley &amp; Sons Ltd.