Novel combination therapy shows strong response in phase 1 trial

In continuation of my update on Sorafenib, Premetrexed,  Vandetanib
"Though phase 1 studies are designed to evaluate the safety of a new therapy, we had strong preclinical evidence suggesting this novel drug combination could work against a variety of cancers, so we hoped that we would see a response in our patients in this early phase trial," said Andrew Poklepovic, M.D., lead investigator on the study. "With this trial, we established a safe dosing schedule, and we will now be testing the efficacy of the therapy in the phase 2 study."

The results of the clinical trial were recently published online by the journal Oncotarget (PMID: 27213589). The study enrolled 37 patients between October 2011 and December 2014. Of those patients, 36 received treatment and 33 were evaluated for response. One patient had a complete response, meaning all detectable traces of the tumor disappeared, while four patients had a partial response, which means that the tumor volume shrank by at least 30 percent. The therapy stabilized disease progression in an additional 15 patients, with some of these patients responding for up to a year. The therapy was found to be particularly active in breast cancer patients.

"Some dose-limiting toxicities associated with pemetrexed were observed in one cohort of patients, but those who were eligible were switched to the dosing schedule of the second cohort, which was found to safe and tolerable," says Poklepovic, medical oncologist and member of the Developmental Therapeutics research program at Massey as well as assistant professor in the Division of Hematology, Oncology and Palliative Care at the VCU School of Medicine.

The trial is based on pre-clinical research conducted by a team of Massey scientists led by Paul Dent, Ph.D., who is the Universal Corporation Chair in Cancer Cell Signaling and a member of the Cancer Cell Signaling research program at Massey, and Richard Moran, Ph.D., who recently retired after 22 years at Massey and more than four decades in the field. Pemetrexed was co-developed by Moran, and is now a first-line therapy for non-small cell lung cancer (NSCLC) and mesothelioma. Sorafenib is used to treat liver, kidney and thyroid cancer. In 2011, a research team led by Dent and including Moran discovered that the two drugs synergize to induce profound killing of cancer cells through a toxic form of autophagy, a process that normally re-cycles components of cells to provide energy for maintaining cell growth and survival. The drug combination hyper-activated the autophagy process within cancer cells, causing them to literally eat themselves to death (PMID: 21622715).

 Sorafenib  Pemetrexed

  Vandetanib    Lapatinib

The phase 2 study is not the only continuation of the research. Because the initial results of the phase 1 study were so promising, Dent started a new project to discover the best "third drug" that could act to further enhance the anti-cancer properties of the pemetrexed and sorafenib combination. This work has also recently been published in Oncotarget, and it showed that the combination therapy could be enhanced by a class of drugs known as ERBB1/2/4 inhibitors (PMID: 27015562).

"We discovered in mouse models of breast cancer that the drugs lapatinib and vandetanib significantly enhanced the anti-tumor effect of the pemetrexed and sorafenib therapy without any apparent toxicity to normal tissue. We made a nearly identical observation when adding the drug afatinib in experiments involving non-small cell lung cancer," says Dent. "Based on this data, we will be submitting a grant application to the National Cancer Institute for funding that will hopefully provide data that could allow us to open a future phase 1 trial testing the addition of an ERBB1/2/4 inhibitor to pemetrexed and sorafenib in patients with advanced solid tumors."

Dent was able to determine that ERBB1/2/4 inhibitors could increase the effectiveness of the combination therapy by using a novel technology called a multiplex assay. The multiplex assay is a broad, unbiased screening approach that allows researchers to simultaneously examine the levels of multiple hormones in the blood and determine the activities of enzymes in cancer cells. Using this technology, the researchers discovered that the enzyme ERBB1 was activated in response to the pemetrexed and sorafenib therapy.

"Unlike alternative methods where a certain degree of guesswork is required, the multiplex assay allowed us to observe exactly how the cancer cells responded to therapy," says Dent. "We were surprised to see that the enzyme ERBB1 was activated because it is ordinarily thought to protect cancer cells from chemotherapy. We went on to successfully use ERBB1/2/4 inhibitors as our third drug because of this unexpected data."

The multiplex assay provided Dent's team with such invaluable additional information about how the sorafenib and pemetrexed combination worked in the mouse models that they will now be using the assay in several of their clinical trials moving forward, including the new phase 2 trial of pemetrexed and sorafenib.

"The multiplex assay will allow us to track specific levels of hormones in the blood as patients undergo treatment, which could potentially give us a molecular 'fingerprint' of the point at which tumors develop resistance to the therapy," says Dent. "Ongoing preclinical experiments show that it could be possible to pinpoint exactly how the cancer cells are developing resistance to therapies, which might eventually allow oncologists to develop in real time a personalized therapy designed to overcome drug resistance in an individual patient's tumor."

Ref : http://www.impactjournals.com/oncotarget/index.php?journal=oncotarget&page=article&op=view&path%5b%5d=9434

Research: Epigenetic factor reduces sensitivity of breast cancer cells to common cancer drug

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In continuation of my update on lapatinib

A surprising, paradoxical relationship between a tumor suppressor molecule and an oncogene may be the key to explaining and working around how breast cancer tumor cells become desensitized to a common cancer drug, found researchers at the Perelman School of Medicine at the University of Pennsylvania. The drug, lapatinib, activates the suppressor called FOXO, in HER2+ breast cancer cells, but then FOXO becomes a turncoat molecule, working with an epigenetic regulator that controls gene expression. This drug-triggered relationship induces the expression of the oncogene c-Myc, leading to reduced sensitivity to the cancer drug and eventually relapse. They published their cover article today in Cancer Cell.

"We found that an epigenetic pathway is crucial for growth of HER2+ cells and this epigenetic factor reduces sensitivity of the cancer cells to lapatinib, a HER2 inhibitor," said senior author Xianxin Hua, MD, PhD, a professor of Cancer Biology. "We need to understand how the body initially responds to these drugs and why there is a relapse and devise a new tool to fix that."

Human epidermal growth factor receptor 2 (HER2) is upregulated in a subset of human breast cancers. The HER2 pathway is mutated in many cancers, which drives tumors, but inhibitors of this pathway, such as lapatinib, have only limited success because cancer cells quickly adapt.

FOXO was normally thought of as the "good guy" molecule that controls cancerous cell growth, while c-Myc, the cancer-promoting molecule, the "bad guy." However, FOXO becomes the agent that desensitizes cells to cancer drugs, so this "good guy" molecule is converted to a "bad guy," during the treatment of the cancer cells with the anti-cancer drug.

"Now that we know about this triangle among FOXO, c-Myc, and the epigenetic pathway, we can stop c-Myc with an epigenetic inhibitor," Hua said. "Multiple epigenetic regulators participate in the drug-desensitizing pathway, so they could serve as new targets to improve therapy for this type of cancer."

Research: Epigenetic factor reduces sensitivity of breast cancer cells to common cancer drug

New combination therapy holds promise for treating HER2-positive breast cancer

Resistance to therapy is a major problem in the cancer field. Even when a treatment initially works, the tumors often find ways around the therapy. Using human cell lines of the HER2-positive breast cancer subtype, researchers from the UNC School of Medicine and UNC Lineberger Comprehensive Cancer Center have detailed the surprising ways in which resistance manifests and how to defeat it before it happens.

The discovery, published today in the journal CELL Reports, provides the experimental evidence for the potential development of a novel combination therapy for HER2-positive breast cancer. The combination includes the FDA approved drug lapatinib (right structure) and a new experimental drug called a BET bromodomain inhibitor -JQ1 (see structure left), which works by disrupting the expression of specific genes.

 

This study, a collaboration of 20 University of North Carolina researchers, is the first time a BET bromodomain inhibitor has been shown to prevent the onset of resistance to drugs such as lapatinib in breast cancer cells.

"This research was done in cell lines of human HER2-positive breast cancer, not in patients; but the results are very striking," said Gary Johnson, PhD, Kenan Distinguished Professor and chair of the department of pharmacology, member of the UNC Lineberger Comprehensive Cancer Center, and senior author of the paper. "The combination treatments are currently being tested in different mouse models of breast cancer. Our goal is to create a new kind of therapy that could help oncologists make the response to treatment more durable and lasting for breast cancer patients."

Ref : http://www.nature.com/nature/journal/v468/n7327/abs/nature09504.html

New combination therapy holds promise for treating HER2-positive breast cancer

Lapatinib benefits found for HER2-positive early-stage patients

In continuation of my update on Lapatinib

Lapatinib benefits found for HER2-positive early-stage patients

Novel way to treat drug-resistant brain tumor cells

In continuation of my update on Lapatinib

Research by Dr. Paul Clark, a scientist in Kuo's lab and the study's lead author, shows why. When cetuximab treatment switches off EGFR activity and should inhibit cancer-cell growth, cancer stem cells compensate by turning on two other EGFR family receptors (ERBB2 and ERBB3) and continue to grow. One of these receptors, ERBB2, is implicated in certain types of chemotherapy-resistant breast cancer. Fortunately, another novel drug already approved by the FDA, lapatinib (see the structure), inhibits ERBB2 activity and signaling by multiple EGFR members.

This study shows that cancer stem-cell growth was markedly inhibited by lapatinib treatment, which results in combined knockout of multiple EGFR family members.

"This is good news, because these drugs target an important mechanism for the (GBM) cancer cells to grow so quickly and evade current therapies, and these molecularly targeted drugs are also well-tolerated by patients and have minimal side effects," Dr. Clark said.

Ref : http://www.med.wisc.edu/news-events/wisconsin-research-team-reveals-novel-way-to-treat-drug-resistant-brain-tumor-cells/37811

Novel way to treat drug-resistant brain tumor cells: New research explains why the incurable brain cancer, glioblastoma multiforme (GBM), is highly resistant to current chemotherapies.

FDAs approval of Lapatinib in combination with Letrozole to treat breast cancer...

In my earlier blog, I mentioned about the combination of Lapatinib and Trastuzumab for breast cancer treatment. Now FDA has  approved Lapatinib in combination with Letrozole (see structure ; Letrozole trade name Femara, an oral non-steroidal aromatase inhibitor for the treatment of hormonally-responsive breast cancer after surgery)  to treat hormone positive and HER2-positive advanced breast cancer in postmenopausal women for whom hormonal therapy is indicated. This drug combination of  Lapatinib  & Letrozole provides women being treated for advanced breast cancer with an important treatment option. 

The entirely oral treatment regimen works by targeting both HER2 and the hormone receptors, thereby slowing the cancer cells' ability to grow or spread. As per the claim by  Dr. Richard Pazdur, (Director, Office of Oncology Drug Products, FDA's Center for Drug Evaluation and Research) women with HER2-positive disease receiving the Lapatinib plus Letrozole combination more than doubled the time they lived without the cancer progressing compared with those receiving Letrozole alone (35 weeks vs. 13 weeks).

Lapatinib, was initially approved in combination with a chemotherapy drug, Xeloda (capecitabine) in 2007. This combination was used to treat women with advanced breast cancer tumors with the HER2 protein who had received prior treatment with chemotherapy drugs, including an anthracycline and a taxane, and Herceptin (trastuzumab), an anti-cancer antibody used to treat HER2-positive advanced breast cancer. Safety information from this study was consistent with previous Lapatinib clinical studies in advanced breast cancer. The most commonly reported side effects of the combination were diarrhea, rash, nausea and fatigue. Still clinical trials are to be carried out, in my opinion its a good achievement...

Ref : http://www.prnewswire.com/news-releases/fda-expands-use-of-approved-breast-cancer-drug-83072502.html

Combination of Lapatinib and Trastuzumab a better treatment for breast cancer....

Lapatinib or lapatinib ditosylate is an orally active chemotherapeutic drug treatment for solid tumours such as breast cancer. Patients who meet specific indication criteria may be prescribed lapatinib as part of combination therapy for breast cancer. On March 13, 2007, FDA approved lapatinib in combination therapy for breast cancer patients already using capecitabine.

Recently, researchers from Duke University Medical Center. Dr. Kimberly Blackwell have found more interesting results when they did try the combination of Trastuzumab (monoclonal antibody). As per the claim by the researchers, Lapatinib plus trastuzumab are significantly better than lapatinib alone in extending the lives of breast cancer patients whose tumors are HER2-positive.

Blackwell says, the combination targeted therapy gave patients more than a four-month survival advantage over those who took lapatinib alone. She says the findings may be the first step toward a chemotherapy-free future. This is the first time that a pair of targeted therapies has been shown to be superior to any intervention that paired a targeted therapy with a hormonal or chemotherapy based approach, she said. The interesting claim by the researchers trastuzumab binds to and blocks part of the HER2 growth factor that appears on the surface of some breast cancer cells while lapatinib binds to a second growth factor, EGFR, and part of HER2 that sits below the cell surface. It's sort of a double whammy, disabling the HER2 protein in two places instead of one......

Ref : http://www.dukehealth.org/health_library/news/targeted_therapy_prolongs_life_in_patients_with_her2_positive_breast_cancer