Phase I study of selumetinib drug shows partial response in pediatric neural tumors

    

    

selumetinib

In an early-phase clinical trial of a new oral drug, selumetinib, children with the common genetic disorder neurofibromatosis type 1 (NF1) and plexiform neurofibromas, tumors of the peripheral nerves, tolerated selumetinib and, in most cases, responded to it with tumor shrinkage. NF1 affects 1 in 3,000 people. The study results appeared Dec. 29, 2016, in the New England Journal of Medicine.

The multicenter phase I clinical trial, which included 24 patients, was led by Brigitte C. Widemann, M.D., acting chief of the National Cancer Institute's (NCI) Pediatric Oncology Branch, and was sponsored by NCI's Cancer Therapy Evaluation Program. The study, conducted at the NIH Clinical Center and three participating sites, took advantage of techniques developed by Dr. Widemann's team that enabled very precise measurement of the plexiform neurofibromas. Experiments in mice that developed neurofibromas due to genetic modifications were performed at Cincinnati Children's Hospital in the laboratory of Nancy Ratner, Ph.D. NCI is part of the National Institutes of Health.

Plexiform neurofibromas develop in up to 50 percent of people with NF1. The majority of these tumors, which can cause significant pain, disability, and disfigurement, are diagnosed in early childhood and grow most rapidly prior to adolescence. Complete surgical removal of the tumors is rarely feasible, and incompletely resected tumors tend to grow back.

The primary aim of this clinical trial was to evaluate the toxicity and safety of selumetinib in patients with NF1 and inoperable plexiform neurofibromas, and, encouragingly, most of the selumetinib-related toxic effects were mild. At present, no therapies are considered effective for NF1-related large plexiform neurofibromas, but, in this trial, partial responses, meaning 20 percent or more reduction in tumor volume, were observed in over 70 percent of the patients.

Responses were observed in tumors that were previously growing at a rate of greater than 20 percent per year, as well as in non-progressing lesions. Tumor shrinkage was maintained long term, for approximately two years, and, as of early 2016, no disease progression had been observed in any trial participant. Additionally, anecdotal evidence of clinical improvement, such as a decrease in tumor-related pain, improvement in motor function, and decreased disfigurement, was reported.

"Some may say that a 20 percent volume reduction is too small to be meaningful, but to me, just stopping the growth of these devastating tumors is an important achievement," said Dr. Widemann. "The difference we see in these patients is truly unprecedented."

The disease-causing gene for NF1 was first identified in 1990 by two independent teams, one of them led by NIH Director Francis S. Collins, Ph.D., M.D., who at the time was chief of Medical Genetics at the University of Michigan. The other team was led by Ray White at the University of Utah. Research to understand the gene's function revealed that deregulation of the RAS signaling pathway was the most likely cause of tumor development. Numerous drugs that target RAS-related signaling pathways have been tested in patients with NF1 in phase I and phase II clinical trials, with disappointing results, hence the interest in selumetinib.

Selumetinib, provided for the study by AstraZeneca, is a selective inhibitor of the MEK protein, a part of the complex network of RAS signaling pathways. The drug has demonstrated activity in some advanced cancers, but it is not yet approved by the U.S. Food and Drug Administration for use in the United States. It is manufactured in capsule form to be taken orally.

Trial enrollment began in September 2011 and 24 children (11 girls, 13 boys) participated. Twice daily doses of the medicine were taken continuously, over a median of 30 month-long treatment cycles. The majority of patients are still continuing with therapy, some for as long as five years, and the long-term treatment has had no observed adverse effect on their development or overall health.

Experiments in mice with similar neurofibromas confirmed the inhibition of the MEK protein function in the tumors. Inhibition of the MEK protein diminished as early as two hours after drug administration. In addition, the animals received treatment with regular interruptions and still demonstrated tumor responses. This indicates that even limited MEK inhibition could cause tumor shrinkage in this disease.

"In the future, we may wish to look at intermittent dosing in patients to minimize toxicity and retain maximal outcomes," said Dr. Widemann.

In some patients, a loss of response to selumetinib with slow regrowth of tumors was observed, particularly after dose reductions. The researchers believe that additional studies are warranted to characterize tumors that no longer respond to selumetinib. NCI is currently sponsoring an ongoing phase II trial of the drug for adults with NF1, in which serial tissue samples are being obtained. This study should provide information about possible mechanisms of resistance to selumetinib.

In addition, a larger phase II pediatric trial is enrolling patients and should help establish the efficacy of selumetinib treatment in children. In this trial, in addition to tumor volume measurements, evaluations are being performed to assess the effect of selumetinib on plexiform neurofibroma related disfigurement, pain, quality of life, and function.

Ref : http://www.nejm.org/doi/full/10.1056/NEJMoa1605943

Read at : Med-News

CU Cancer Center study reports 'robust antitumor activity' of TAK-733 drug in mouse models of colorectal cancer

In continuation of my update on TAK-733

A University of Colorado Cancer Center study recently published online ahead of print in the journal Oncotarget reports "robust antitumor activity" of the drug TAK-733 in cells and mouse models of colorectal cancer. In all, 42 of 54 tested cell lines were sensitive to the drug, as were 15 of 20 tumors grown on mice from patient samples. Nine of these patient-derived tumors showed regression, meaning that tumor tumors shrank in response to the drug.

"This was a large preclinical study that showed good activity for the drug and gave preliminary evidence for a potential biomarker that could predict which tumors would respond best to the drug," says Christopher Lieu, MD, investigator at the CU Cancer Center and assistant professor of medical oncology at the University of Colorado School of Medicine.

Specifically, the drug intercedes in the MAPK signaling pathway, a cascade of cellular communication that controls cell growth and survival and is frequently altered in many cancers (especially including melanoma, non-small cell lung cancer, and colorectal cancer). The drug does this by silencing an essential link in this signaling chain, namely the molecule MEK. Without activity of the MEK kinase, MAPK signaling cannot occur and instead of surviving and proliferating, cancer cells dependent on this pathway die.

A handful of successful MEK kinase inhibitors exist, including trametinib and selumetinib.

"The preclinical results for TAK-733 were fairly impressive. We had high hopes that TAK-733 could be a next-generation MEK inhibitor that might support or replace the use of current drugs," Lieu says.

The study seemed a perfect precursor to a human clinical trial of TAK-733 in colorectal cancer.

CU Cancer Center study reports 'robust antitumor activity' of TAK-733 drug in mouse models of colorectal cancer

Breakthrough in ovarian cancer: Selumetinib

In continuation  of my update on Seumetinab

We know that, Selumetinib (AZD6244) is a drug being investigated for the treatment of various types of cancer, for example non-small cell lung cancer (NSCLC). 

Mode of action : The gene BRAF is part of the MAPK/ERK pathway, a chain of proteins in cells that communicates input from growth factors. Activating mutations in the BRAF gene, primarily V600E (meaning that the amino acid valine in position 600 is replaced by glutamic acid), are associated with lower survival rates in patients with papillary thyroid cancer. Another type of mutation that leads to undue activation of this pathway occurs in the gene KRAS and is found in NSCLC. A possibility of reducing the activity of the MAPK/ERK pathway is to block the enzyme MAPK kinase (MEK), immediately downstream of BRAF, with the drug selumetinib. More specifically, selumetinib blocks the subtypes MEK1 and MEK2 of this enzyme....

The study was initially developed in 2007, with 52 patients enrolled for the Phase II clinical trial between December 2007 and November 2009. Patients were given 50 milligrams of selumetinib orally twice daily. Of those participants, eight had a measurable decrease in tumor size, seven had partial responses and 34 patients saw their tumors stabilize. The findings suggest that inhibitors of the MAPK pathway warrant further investigation in patients with low-grade ovarian cancer.

"There just aren't very good treatments for low-grade ovarian cancer, so this discovery opens up a lot of new exciting possibilities for us," Dr. Farley said. He added that Phase III of this trial is scheduled to begin in the next few weeks, with that trial to be the "definitive test" before the treatment becomes available to the general population.

Ref : http://www.thelancet.com/journals/lanonc/article/PIIS1470-2045(12)70572-7/fulltext



Breakthrough in ovarian cancer: Selumetinib

Drug Combo Tackling Solid Tumors

Cancer Research UK's Drug Development Office has opened the first trial of a new drug combination in patients with advanced solid tumors and in a subset of patients who have non-small cell lung cancer. This trial will combine two compounds that aim to starve the tumors while simultaneously blocking cancer cell growth.

The study will take place across three UK hospitals. The Churchill Hospital, Oxford is the lead center. The trial of up to 48 patients will run in two stages. In the first stage patients with any solid tumor will each receive a drug called vandetanib (below left) and an investigational drug called selumetinib (right structure below)AZD6244, ARRY142886). In the second stage patients with non-small cell lung cancer (NSCLC) will receive the combination.

This is the first time the compounds have been trialled together. It is hoped that combining these treatments will increase the number of cancer ‘weakspots’ targeted at the same time.

Chief investigator, Dr. Denis Talbot, consultant medical oncologist at Oxford University Hospitals NHS Trust and Cancer Research UK clinician at The University of Oxford, said: “Therapies for lung cancer often become ineffective because the disease becomes resistant to treatment, so we’re delighted to launch this trial to test a new approach that we hope will help people with this common disease.

“There is progress being made in the treatment of lung cancer but survival rates still remain low. This is because the majority of patients – up to two thirds – are diagnosed once the cancer has already spread to other organs when it’s more difficult to treat successfully.

 “We hope that this new approach may eventually contribute to increased survival for lung cancer patients.”

Ref : http://cancerhelp.cancerresearchuk.org/trials/a-trial-of-vandetanib-and-selumetinib-for-solid-tumours-including-nsclc-vansel-1