June 13, 2012

FDA Decision Delayed for Truvada in HIV PrEP

From Medscape Medical News

Emma Hitt, PhD

June 11, 2012 — The US Food and Drug Administration (FDA) has delayed its decision on allowing the use of tenofovir disoproxil fumarate/emtricitabine (Truvada, Gilead) as preexposure prophylaxis (PrEP) so that the proposed risk evaluation and mitigation strategy (REMS) can be reviewed.

In early May, the FDA's Antiviral Drugs Advisory Committee strongly backed approval of the first-ever drug for the prevention of sexually acquired HIV-1 infection.

However, concerns by the panel at the time included that people may neglect condom use if they feel they are protected by PrEP. Panelists were also concerned that uninfected people taking PrEP who become infected with HIV may not switch to a 3-drug regimen as recommended.

According to the company, the FDA has postponed the target date to September 14 so it can review Gilead's REMS plan to help ensure that patients will not misuse the drug.

The committee's recommendation for supplemental approval of tenofovir/emtricitabine for PrEP is based on the findings of 3 large randomized controlled clinical trials in men who have sex with men and transgender women (iPrEx) and in heterosexual men and women (Partners PrEP and TDF2).

The drug's efficacy was highest in people who adhered to daily dosing (about 10% of participants), and overall, PrEP resulted in a 44% to nearly an 80% reduction in risk of contracting HIV, depending on the level of adherence and drug availability.

After the PrEP trial results came out, the US Centers for Disease Control and Prevention (CDC) developed interim guidance in January 2011 for physicians electing to provide PrEP for HIV prevention among men who have sex with men.

At this time, the CDC recommends that PrEP be used only men who have sex with men. In addition, to minimize the risk for drug resistance, PrEP should not be started in persons with signs or symptoms of acute viral infection unless HIV-negative status is confirmed by HIV RNA testing or a repeat antibody test is performed after the viral syndrome resolves.

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WOBURN, Massachusetts and TOKYO, June 11, 2012 /PRNewswire/ --

  • Significant improvements in time to progression (TTP) and overall survival (OS) observed in patients on tivantinib vs. on placebo whose tumors were MET-high
  • Hepatocellular carcinoma (HCC) is the most common primary liver cancer and on the rise worldwide[1]
  • Phase 3 study among previously treated HCC patients with MET-high tumors is currently being planned with tivantinib

ArQule, Inc. (Nasdaq: ARQL) and Daiichi Sankyo Co., Ltd. (TSE: 4568) announced final results from a randomized, placebo-controlled, double-blind, phase 2 clinical trial with the selective MET inhibitor tivantinib

as a single-agent, investigational, second-line treatment in hepatocellular carcinoma (HCC). The data was presented at the 48th Annual Meeting of the American Society of Clinical Oncology (ASCO) (abstract number 4006).

The 107 patients in the trial had unresectable HCC and had disease progression after first-line therapy or were unable to tolerate the first-line therapy. Patients were randomized to receive tivantinib at 360 milligrams (mg) twice daily or 240 mg twice daily or placebo (2:1 tivantinib:placebo). The primary endpoint was time to progression (TTP) in the intent to treat (ITT) population. Other study endpoints were disease control rate (DCR), progression free survival (PFS), overall survival (OS), as well as safety for the ITT population and pre-defined MET-high or MET-low cohorts (as defined by immunohistochemistry).

A statistically significant 56 percent improvement as compared to placebo was seen in TTP in the ITT population (hazard ratio [HR] = 0.64; 90 percent confidence intervals [CI] = 0.43-0.94; log rank p-value = 0.04). The median TTP in tivantinib arm was 1.6 months and 1.4 months in the placebo arm.

In the MET-high cohort, there were statistically significant improvements in TTP, PFS and OS:

  • Median OS in tivantinib arm was 7.2 months and 3.8 months in the placebo arm (HR = 0.38; 95 percent CI = 0.18-0.81; log rank p-value = 0.01)
  • Median TTP was 2.9 months in the tivantinib arm and 1.5 months in the placebo arm (HR = 0.43; 95 percent CI = 0.19-0.97; log rank p-value = 0.03)
  • Median PFS was 2.4 months in the tivantinib arm and 1.5 months in the placebo arm (HR = 0.45; 95 percent CI = 0.21-0.95; log rank p-value = 0.02).

There was no significant difference in TTP or OS between tivantinib and placebo in the MET-low cohorts.

Adverse events were reported at similar rates in the treatment and placebo arms of the trial, except for a higher incidence of fatigue and hematologic events, including neutropenia and anemia, in tivantinib-treated patients. The incidence of hematologic events decreased following dose reduction of tivantinib from 360 mg twice daily to 240 mg twice daily. Due to increased incidence of neutropenia in the 360 mg treatment group, the tivantinib dose was reduced to 240 mg twice daily for all patients.

"Patients living with this disease need more options to slow progression. The findings from this tivantinib study represent the first randomized data reported in HCC with an investigational MET inhibitor, as single-agent therapy in second-line treatment," said Lorenza Rimassa, Deputy Director, Medical Oncology Unit, Humanitas Cancer Center, Milan, Italy. "The data suggest that patients significantly benefited in time to progression and, importantly, those in a biologically relevant MET-high subgroup had an additional significant advantage in overall survival."

"Research has shown that MET is a signaling pathway associated with poor outcomes in many cancers, including liver cancer and non-small cell lung cancer (NSCLC)," said Glenn Gormley, MD, PhD, Global Head of Research & Development and Senior Executive Officer, Daiichi Sankyo Co., Ltd. "The strong overall survival results among HCC patients in this trial whose tumors were MET-high reinforce this previous research that defines MET as a critical pathway in cancer as well as the activity of tivantinib as a MET inhibitor."

About Hepatocellular Carcinoma (HCC)

Globally, liver cancer is the sixth most common cancer (749,000 new cases per year), accounting for 7 percent of all cancers, and is the third cause of cancer related death (692,000 cases per year).[2]. HCC represents more than 90 percent of primary liver cancers. [3] Chronic hepatitis B and C are recognized as the major factors worldwide increasing the risk of HCC, with risk being even greater in the presence of co-infection with these viruses.[4] Cirrhosis is also a risk factor for development of HCC.

About Tivantinib and the MET pathway

Tivantinib is an orally administered, selective inhibitor of MET, a receptor tyrosine kinase.

In healthy adult cells, MET is present in normal levels to support natural cellular function, but in cancer cells MET is inappropriately and continuously activated for unknown reasons. When abnormally activated, MET plays multiple roles in aspects of human cancer, including cancer cell growth, survival, angiogenesis, invasion and metastasis.

Tivantinib is currently in phase 3 development and has not yet been approved for any indication. Tivantinib has the potential to be a first-in-class MET inhibitor for the treatment of non-small cell lung cancer (NSCLC) and is currently being studied for other indications including liver and colorectal cancers.

About ArQule and Daiichi Sankyo Co., Ltd.

In December 2008, ArQule and Daiichi Sankyo signed a license, co-development and co-commercialization agreement for tivantinib (ARQ 197) in the U.S., Europe, South America and the rest of the world, excluding Japan, China (including Hong Kong), South Korea and Taiwan.

About ArQule

ArQule is a biotechnology company engaged in the research and development of next-generation, small-molecule cancer therapeutics. The Company's targeted, broad-spectrum products and research programs are focused on key biological processes that are central to human cancers. ArQule's lead product candidate, in phase 2 and phase 3 clinical development together with development and commercialization partner, Daiichi Sankyo, Co. Ltd., is tivantinib, an oral, selective inhibitor of the MET receptor tyrosine kinase. The Company's pipeline consists of ARQ 621, designed to inhibit the Eg5 kinesin motor protein, and ARQ 736, designed to inhibit the RAF kinases. ArQule's current discovery efforts, which are based on the ArQule Kinase Inhibitor Platform (AKIP™), are focused on the identification of novel kinase inhibitors that are potent, selective and do not compete with ATP (adenosine triphosphate) for binding to the kinase.

About Daiichi Sankyo

The Daiichi Sankyo Group is dedicated to the creation and supply of innovative pharmaceutical products to address the diversified, unmet medical needs of patients in both mature and emerging markets. While maintaining its portfolio of marketed pharmaceuticals for hypertension, hyperlipidemia, and bacterial infections, the Group is engaged in the development of treatments for thrombotic disorders and focused on the discovery of novel oncology and cardiovascular-metabolic therapies. Furthermore, the Daiichi Sankyo Group has created a "Hybrid Business Model," which will respond to market and customer diversity and optimize growth opportunities across the value chain. For more information, please visit http://www.daiichisankyo.com.

This press release contains statements regarding the clinical trials with tivantinib (ARQ 197) by ArQule and its business partner, Daiichi Sankyo. These statements are based on the current beliefs and expectations of both companies, and are subject to risks and uncertainties that could cause actual results to differ materially. Positive information about pre-clinical and early stage clinical trial results does not ensure that later stage or larger scale clinical trials will be successful. For example, tivantinib may not demonstrate a promising therapeutic effect; in addition, it may not demonstrate an appropriate safety profile in current or later stage or larger scale clinical trials as a result of known or as yet unanticipated side effects. The results achieved in later stage trials may not be sufficient to meet applicable regulatory standards or to justify further development. Problems or delays may arise during clinical trials or in the course of developing, testing or manufacturing these compounds that could lead ArQule or its partners to discontinue development. Even if later stage clinical trials are successful, unexpected concerns may arise from analysis of data or from additional data. Obstacles may arise or issues may be identified in connection with review of clinical data with regulatory authorities. Regulatory authorities may disagree with ArQule's view of the data or require additional data or information or additional studies. In addition, the planned timing of initiation and completion of clinical trials for tivantinib are subject to the ability of ArQule, Daiichi Sankyo, and Kyowa Hakko Kirin, a licensee of tivantinib, to enroll patients, enter into agreements with clinical trial sites and investigators, and overcome technical hurdles and other issues related to the conduct of the trials for which each of them is responsible. There is a risk that these issues may not be successfully resolved. Drug development involves a high degree of risk. Only a small number of research and development programs result in the commercialization of a product. Positive pre-clinical data may not be supported in later stages of development. Furthermore, ArQule may not have the financial or human resources to successfully pursue drug discovery in the future. Moreover, with respect to partnered programs, even if certain compounds show initial promise, Daiichi Sankyo or Kyowa Hakko Kirin may decide not to license or continue to develop them, as the case may be. In addition, Daiichi Sankyo and Kyowa Hakko Kirin have certain rights to unilaterally terminate their agreements with ArQule. If either company were to do so, ArQule might not be able to complete development and commercialization of the applicable licensed products on its own. For more detailed information on the risks and uncertainties associated with ArQule's drug development and other activities, see ArQule's periodic reports filed with the Securities and Exchange Commission. Neither ArQule nor Daiichi Sankyo undertake any obligation to publicly update any forward-looking statements.

1. Hepatocellular carcinoma: Epidemiology, risk factors and pathogenesis. World Journal of Gastroenterology 14(27): 4300-08, 2008.

2. EASL-EORTC Clinical Practice Guidelines: Management of hepatocellular carcinoma. Journal of Hepatology. 2012;56: 908-943

3. EASL-EORTC Clinical Practice Guidelines: Management of hepatocellular carcinoma. Journal of Hepatology. 2012;56: 908-943

4. Chiaramonte M, Stroffolini T, Vian A, et al.: Rate of incidence of hepatocellular carcinoma in patients with compensated viral cirrhosis. Cancer 85 (10): 2132-37, 1999.

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The Ribbon on His Shoulder: Perceptions of HIV in America Today

Dale Cooper

Posted: 06/12/2012 4:04 pm

Thirty-one years ago the U.S. Centers for Disease Control and Prevention reported on an unknown virus that was attacking the immune system of five gay men in Los Angeles. It was soon dubbed "gay-related immune deficiency," or GRID. It was labeled with that name by a scientific/medical establishment grappling with a rapidly spreading syndrome, a gay disease, the effects and stigma of which have had a lasting impact.

Clusters of Kaposi's sarcoma and Pneumocystis pneumonia, illnesses closely associated with GRID, began to be reported among Haitians who had recently immigrated to the United States, hemophiliacs, female sexual partners of people with the virus, and recipients of blood transfusions.

By the following summer, the illness had spread nationwide and had been given the name AIDS (for acquired immunodeficiency syndrome). In 1984 the U.S. Department of Health and Human Services announced that the probable cause of AIDS had been discovered: the retrovirus subsequently named the human immunodeficiency virus, or HIV.

This year's AIDS/LifeCycle raised $13 million to help care for those already affected by AIDS and HIV, especially the uninsured, and to fund prevention services to reduce the spread of the disease. While this is an incredible collective accomplishment, the value of the HIV/AIDS awareness and education the ride creates can't be underestimated. Before packing for the seven-day trip, each rider and roadie helped spread awareness about HIV/AIDS by contacting family, friends, coworkers, and others to ask for their support in ending AIDS. More than 95,000 of them were inspired to sponsor their participation in AIDS/LifeCycle.

Also along for the ride are members of the media: journalists, bloggers, photographers, and videographers, who ensure that this minority community of people affected by HIV/AIDS and their allies can share their stories and get their voices heard. The participants in ALC, the cyclists and the roadies, all contribute to spreading understanding and raising consciousness, but there is still work to do, especially in light of these surprising statistics:

  • One in five people living with HIV is not aware of it.
  • The share of Americans naming HIV/AIDS as the most urgent health problem facing the nation has dropped precipitously, from 44 percent in 1995 to 7 percent in 2011.
  • The share of young adults (including young African Americans) saying they are personally concerned about becoming infected with HIV has declined steadily since the late 1990s, from 30 percent then to 24 percent now.

Decreasing awareness and education about HIV means fewer people are considering their risk for contracting the virus and are less likely to get tested. Additionally, a lack of understanding regarding the seriousness of the AIDS epidemic can lead to less funding from private entities and government agencies.

Alarmingly, this drop in overall public concern for HIV/AIDS coincides with a sharp uptick in rates of new infections among African Americans and Latinos, whose rates of infection compared to Caucasians are nine and three times higher, respectively. And most of those newly infected, 61 percent, are gay and bisexual men.

More than 30 years into the epidemic, one third of Americans (34 percent) still harbor at least one misconception about HIV transmission:

  • 1 in 4 people do not know that HIV cannot be transmitted through sharing a drinking glass.
  • 16 percent of people think touching a toilet seat can spread HIV.
  • 12 percent of people think swimming in a pool with someone who is HIV-positive could infect them with the virus.

All those perceptions are remnants of an AIDS stigma, spurred by misinformation and phobia, that continues to exert a powerful sway over the American public. People who harbor these misconceptions about HIV transmission are more likely to say they would be uncomfortable working with someone with HIV: 43 percent, compared with 13 percent of those who know that HIV cannot be transmitted in these ways.

Additionally:

  • Almost half (47 percent) do not know that a pregnant woman with HIV can take drugs to reduce the risk of her baby being born infected.
  • About one in five (19 percent) are unaware that there is no cure for AIDS.
  • About 12 percent do not know that there are drug treatment options that can lengthen the lives of people with HIV.
  • About a quarter (27 percent) mistakenly believe (or are unsure whether) Magic Johnson has been cured of AIDS.
  • About a quarter (24 percent) mistakenly believes that there is currently a vaccine available to keep people from becoming infected.

As media coverage of HIV/AIDS declines and misconceptions and stigma persist, the visibility and awareness created by the AIDS/LifeCycle participants becomes even more important. Riders and roadies should not underestimate the importance of the mission they represent or the red ribbons they may sport on their bikes, vehicles, jerseys, and helmets as they bike through the communities along their seven-day route.

The seemingly insignificant actions of cyclists, such as sharing pictures from the ride via social media, or sending tweets about their experience, actually reinforce in the minds of their friends and loved ones that AIDS is still here. Every conversation with a resident of the communities through which AIDS/LifeCycle travels, and every driver passes one of the 2,225 cyclists is reminded that AIDS is still here. With the help of a community that is committed to caring, however, it will not be here to stay.

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Posted: 06/13/2012 11:34 am Updated: 06/13/2012 3:39 pm

A new finding is leaving some scientists puzzled over whether Timothy Ray Brown, the "Berlin patient" who was supposedly cured of his HIV after receiving bone marrow transplants in 2007 and 2008, has actually been completely rid of the virus.

Brown initially received the bone marrow stem cell transplants because of non HIV-related leukemia, but the transplants came from a person whose cells were HIV-resistant. After he had received the transplants, Brown's HIV didn't come back and he didn't have to take antiretroviral medication anymore. Scientists considered him cured.

But a presentation at the International Workshop on HIV & Hepatitis Virus last week in Spain suggested that Brown still has traces of HIV genes in his body. But what this means exactly is being interpreted differently among scientists, NPR reported.

HIV researcher Alain Lafeuillade of the General Hospital in France, who was not involved in the new finding, offered his interpretation of the results in a statement:

New data presented at the Sitges workshop by Dr S. Yukl group from San Francisco challenged these results as they showed persistence of low levels of HIV viremia in this patient, and HIV DNA in his rectal cells. These HIV strains were found to be different from those initially present in this patient back in 2006, and different from each other. Although HIV could have evolved and persist over the last 5 years, these data also raise the possibility that the patient has been reinfected.

However, Brown said that he has not been reinfected. "That is not the case," Brown told NPR. "It's very difficult for me to listen to those things and read those things."

Plus, NPR noted that even if pieces of the virus were found in Brown's body, there was no sign they were actually able to replicate, meaning "he may be functionally cured, even if he's not totally free of HIV."

The scientists who conducted the study that identified the traces of HIV said that their findings were not meant to be taken as a definitive evidence that Brown had been -- or not been -- cured, the Science Insider blog reported.

"There are some signals of the virus and we don't know if they are real or contamination, and, at this point, we can't say for sure whether there's been complete eradication of HIV," Steven Yukl, of the University of California, San Francisco, who presented the data, told Science Insider. "The point of the presentation was to raise the question of how do we define a cure and, at this level of detection, how do we know the signal is real?"

For more on the case, click over to NPR and read the full story.

The initial report that Brown was "cured" of HIV was published in the journal Blood.

“I quit taking my HIV medication the day that I got the transplant and haven’t had to take any since,” Brown told CBS San Francisco at the time.

However, doctors told CBS San Francisco when the news came out that the bone marrow stem cell transplant approach would not work for everyone with HIV because of the challenges of stem cell transplantation and finding the right match for a donor.

"This is not prime time to me at all," HIV researcher Dr. Anthony Fauci, director of the National Institutes of Allergy and Infectious Diseases, told Fox News at the time. "This is a very unusual situation that has little practical application for a simple reason. This donor not only had to be a good compatible match, but the donor had to have a genetic defect of cells that do not express the receptor that the HIV virus needs to enter the cell."

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Michael B. A. Oldstone, Ph.D., is a Professor in the Scripps Research Institute Department of Immunology and Microbial Science.

Public release date: 13-Jun-2012

Contact: Mika Ono
mikaono@scripps.edu
858-784-2052
Scripps Research Institute

LA JOLLA, CA – June 13, 2012 -- Scientists from The Scripps Research Institute have shown a single protein can make the difference between an infection clearing out of the body or persisting for life. The results also show where the defects occur in the immune system without the protein and offer the possibility that targeting this signaling pathway could be beneficial for treatment of persistent viral infections in humans. Currently hundreds of millions of people around the world are afflicted with persistent viral infections such as HIV, HCV, and HBV.

The new study is published in the June 14, 2012 issue of the journal Cell Host & Microbe.

In the new study, a team led by Scripps Research Professor Michael Oldstone showed what happened when a mouse engineered without the protein TLR7 was infected with lymphocytic choriomeningitis virus (LCMV), a virus employed to study the response of the immune system to microbes. While normal mice infected with a LCMV variant called Cl 13 could clear a persistent infection in 60 to 90 days, TLR7-deficient mice were unable to purge the infection throughout their lives.

"It is well known that RNA from many viruses, including influenza, HIV, and hepatitis C, induce signaling through TLR7," said Kevin Walsh, a research associate in Oldstone's lab and the first author of the study. "We demonstrated that TLR7 plays a significant role in the generation of immune responses required to clear persistent LCMV infection."

'Biological Warfare'

In terms of the constant biological warfare between host and microbes, the body is not so much a temple as it is a medieval city. An infectious agent can invade through the skin or mucosa, essentially scaling the walls. Once it's inside it has to deal with the body's first responders, called Toll-like receptors (TLR). These receptors are a pattern-recognition system to alert the immune system. TLRs form the first line of defense specifically by recognizing molecules of the invading pathogen.

Ten TLRs have been identified in humans. One of these, TLR7, is located inside the cell within endosomes and the RNA of viruses are detected after they have entered the cell. "TLR7 is a very important receptor in terms of viruses," noted Oldstone.

In the current study, the researchers chose to use LCMV to understand the role of TLR7. LCMV is, according to Oldstone, "has been, and continues to be a Rosetta Stone to explain basic concepts in immunology and virology."

Once it was clear that the absence of TLR7 compromised the immune system's ability to clear LCMV infection, Oldstone, Walsh, and their colleagues explored what was happening downstream of the receptor.

Interestingly, the research demonstrated that even when immune memory cells, which "learn" to fight an infection and impart long-term immunity, were transferred from TLR7-sufficient mice to TLR7-deficient mice, those deficient mice still couldn't clear the infection.

"The environment within TLR7-deficient mice suppressed the ability of these memory cells to clear the infection," said Walsh.

Surprisingly Tired Cells

The team noticed several unexpected things. First, in the TLR7-deficient mice, there was a profusion of tired T cells. "You see more T cells in TLR7-deficient mice early after infection, but they don't actually clear the infection," said Walsh. "Even though there were more of them, they were less functional." Second, immune system B cells were severely hampered; specifically, the differentiation and maturation of B cells to plasma cells, cells responsible for generating antiviral antibody, was aborted. Thus, both essential arms of the immune system, cellular and humoral, required to clear viral infection were compromised.

Exhausted T cells produce fewer molecules to attack and destroy infected cells. Exhaustion occurs in TLR7-sufficient environments, too—but in those cases there is a resurrection of the T cells 60 to 90 days following infection with LCMV Cl 13, which allows the body to purge the virus. In the TLR7-deficient environment, this resurrection never happens. The exhausted T cells linger, as does the infection. T cell exhaustion is also found in HIV and hepatitis B and C infection.

"A number of phenomena that LCMV uses to cause a persistent infection is the same that HIV, hepatitis C and B use," said Oldstone. "That's what makes our observation important. It means that if you understood what is in the environment with loss of TLR7 signaling and how to correct that, you'd have a better chance of treating those persistent human infections. We know how to treat it in the mouse, and people are working very hard to do the treatments in humans."

###

In addition to Oldstone and Walsh, authors of the paper, "Toll-like receptor 7 is required for effective adaptive immune responses that prevent persistent virus infection," were John R. Teijaro, Megan J. Welch, Daniel M. Fremgen, and Karl von Tiehl of Scripps Research; Elina I. Zuniga of the University of California, San Diego; Shawn D. Blackburn and E. John Wherry of the University of Pennsylvania School of Medicine; and Richard A. Flavell of Yale University.

This research was supported by the US National Institutes of Health.

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ScienceDaily (June 13, 2012) — Scientists at The Scripps Research Institute have used a powerful new chemical-screening method to find compounds that inhibit the activity of human immunodeficiency virus (HIV), the virus that causes AIDS. Unlike existing anti-HIV drugs, the compounds bind to a protein called "nucelocapsid," which is unlikely to mutate into drug-resistant forms.

"Most of the nucleocapsid-inhibiting compounds that have been identified to date are very toxic, but our screening method identified inhibitors that are less toxic and thus more likely to lead to useful drugs," said Scripps Research Associate Professor Bruce Torbett. Torbett is the senior author of the new report, which appears in the June 14, 2012 print issue of the Journal of Medicinal Chemistry.

HIV's nucleocapsid protein binds to the viral genome to package and protect it, and plays a key role in the assembly of new virus copies, as well as in the reverse transcription of the viral genome into DNA. It has long been a target of HIV drug developers because it grabs hold of the viral genome using protein structures -- known as zinc knuckles -- that can't change much without losing their functionality. It thus is thought to have little room to mutate into drug-resistant forms, in contrast with other HIV proteins.

Screening Out Toxicity

However, despite almost two decades of research, there are still no FDA-approved drugs that target HIV's nucleocapsid protein and its zinc knuckle structures. One reason is that similar structures exist on many healthy cellular proteins; thus compounds that target them are apt to have unwanted side effects. "When researchers have targeted these nucleocapsid zinc knuckles in the past, they've usually ended up producing toxicity," Torbett said.

To increase the chances of finding safe compounds, Torbett and his colleagues -- postdoctoral researcher Sebastian Breuer, the study's first author, and Max Chang and Jinyun Yuan, also postdoctoral researchers -- began with the Maybridge HitFinder Collection, a library of 14,400 chemical compounds from which many broadly toxic molecules have already been excluded. The Scripps Research Molecular Screening Center maintains the latest robotic equipment for quickly applying chemical tests to such libraries. With the help of screening expert Scripps Research Professor Hugh Rosen, Screening Center Staff Scientist Steven Brown, and Research Assistant Jacqueline Lohse, Breuer applied a special combination of screening tests to the Maybridge library to rapidly zero in on effective and safe nucleocapsid-inhibiting compounds.

The first screening test employed a technique known as fluorescence polarization to measure the ability of each compound in the library to displace the binding of the viral genome to the nucleocapsid protein. (The study focused on the virus type HIV-1, which accounts for the vast majority of HIV infections outside West Africa.) The second test, using differential scanning fluorimetry, was applied to the 101 compounds that passed the first test; it identified those that perform the displacement by binding strongly to the nucleocapsid protein rather than to the viral genome.

After eliminating the weaker and more toxic candidates with further tests, Breuer, Torbett, and their colleagues ended up with 10 compounds. Detailed analyses of these yielded two that were sufficiently powerful at inhibiting viral infectivity in cell culture tests, without being unacceptably toxic.

"We went very quickly from having a concept to having these two inhibitors with demonstrated anti-HIV activity in cells," said Torbett.

Searching for the 'Sweet Spot'

With his Scripps Research colleagues M. G. Finn and Valery Fokin, Torbett now plans to evaluate compounds that are closely related to the two inhibitors to see if the scientists can find any that are even more safe and effective. Torbett and colleagues also plan to apply the same combination-screening method to larger compound libraries to identify entirely new nucleocapsid-inhibiting compounds.

To gain a better understanding of how these inhibitors work, Torbett is also collaborating with Scripps Research structural biologists, including David Stout and Arthur Olson, and virologist John Elder to perform X-ray crystallography studies of the inhibitors in combination with the HIV nucleocapsid protein.

"The overall goal here is to find a 'sweet spot' on the nucleocapsid protein that can be targeted effectively by a small-molecule drug without causing toxicity," Torbett said.

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Acetaminophen overdoses common cause of kids' liver failure

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Acetaminophen which is an ingredient in a variety of over-the-counter and prescription medications, is also one of the leading causes of acute liver failure. (Scott Olson/Getty )

Dosing misunderstanding common among adults

CBC News Posted: Jun 4, 2012 2:11 PM ET Last Updated: Jun 4, 2012 3:17 PM ET
Acetaminophen painkiller overdoses can cause life-threatening liver failure in children but the problem is avoidable, Canadian doctors say.

"Acetaminophen overdose is a major cause of acute liver failure and is the most common identifiable cause of acute liver failure in children," Dr. Rod Lim of the Children's Hospital at London Health Sciences Centre and his co-authors wrote in Monday's issue of the Canadian Medical Association Journal.

Spoons are often used by parents but are inaccurate, as are liquid droppers, the pediatricians said.

They suggested:

  • Better packaging to make it easier for parents to calculate and give an appropriate dose.
  • Keeping children's acetaminophen behind the counter so a pharmacist can give parents written information on what dose and volume to use based on the child's weight.
  • Doctors should keep in mind that infants' livers metabolize acetaminophen differently than adults, which can influence the risk of liver damage in young patients.

The team reported on a 22-day-old boy they successfully treated in the emergency department at a community hospital after an accidental overdose.

A doctor told the newborn's parents to give him 40 milligrams of acetaminophen before bringing him in for a circumcision.

The boy weighed 4.1 kilograms so the intended dose was 10 milligrams per kilogram.

The bottle showed a concentration of acetaminophen of 80 milligrams per millilitre, which the parents misinterpreted as meaning the bottle contained 80 milligrams of acetaminophen in total. They gave him 10 millilitres, or about half the bottle.

The error was discovered during the circumcision.

He recovered after intravenous treatment and showed no evidence of any long-term consequences of the accidental overdose, the doctors said.

Substantial potential for errors

The boy's case illustrates how well-educated parents miscalculated the dose of acetaminophen.

The weight-based dosing and conversion from milligrams of weight to millilitres of volume for many liquid preparations of children's medications can pose challenges, doctors say.

Between 2000 and 2004 in the U.S., 24 deaths were reported to poison control centres, and one third were due to acetaminophen overdose, the researchers said in noted comparable Canadian data have not yet been compiled.

In 2009, Health Canada revised its labelling standards for products containing acetaminophen and mandated that weight-based dosing charts be included with the products.

Heavy users of acetaminophen

Despite regulatory moves in Canada and the U.S., the authors said there's still room to improve.

Last week, U.S. researchers concluded many adults are also at risk of overdosing from over-the-counter pain relievers containing acetaminophen, like Tylenol.

The researchers interviewed 500 adults patients at outpatient general medicine clinics in Atlanta and Chicago. More than half had used acetaminophen in the past six months and 19 per cent said they were heavy users who took acetaminophen every day or a couple of times a week.

Nearly a quarter, or 23.8 per cent, of the participants showed they would overdose on a single over-the-counter acetaminophen product by exceeding a dose of four grams in a 24-hour period.

About five per cent made serious errors by taking more than six grams over 24 hours.

And 45.6 per cent of the adults demonstrated they would overdose by 'double-dipping' with two acetaminophen-containing products.

"Misunderstanding of the active ingredient and proper instructions for over-the-counter medications containing acetaminophen is common," Dr. Michael Wolf, an associate professor of medicine at Northwestern University in Chicago and his co-authors wrote in the Journal of General Internal Medicine.

"The potential for errors and adverse events associated with unintentional misuse of these products is substantial, particularly among heavy users of acetaminophen and those with limited literacy."

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June 7, 2012

New research confirms that successful pregnancies are common for female liver transplant recipients. The study appearing in the June issue of Liver Transplantation, a journal published by Wiley-Blackwell on behalf of the American Association for the Study of Liver Diseases, found miscarriage risk was lower and the live birth rate higher among women following liver transplantation than in the general U.S. population.

In 1978, Walcott et al. documented the first known pregnancy in a liver transplant recipient, which resulted in a successful delivery with both mother and infant in excellent health. Medical evidence reports there are currently 14,000 American women of reproductive age who have received liver transplants and another 500 undergo the procedure each year. While previous studies have documented good reproductive function in women following liver transplant, pregnancy outcomes and maternal-fetal risks assessments are limited.

For the present study, a team led by Dr. Dorry Segev, Director of Clinical Research in Transplant Surgery at Johns Hopkins Medical Institutions in Baltimore, Md., systematically reviewed medical literature articles from 2000 to 2011 to identify studies pertaining to pregnancy outcomes among liver transplant recipients. Maternal complications, delivery outcomes, birth information, and transplant-related data were also analyzed.

Eight studies met the inclusion criteria, which included 450 pregnancies among 306 liver transplant recipients. Following transplantation the live birth rate was 77% compared to 67% in birth in the general U.S. population. The rate was similar to the rate after kidney transplant at 77% and 74%, respectively. Miscarriages among women following kidney (14%) and liver (16%) transplants were lower than the general population (17%).

Rates for preeclampsia, cesarean section and preterm delivery were higher in liver transplant patients at 22%, 45%, and 39% than in the general population at 4%, 21% and 13%, respectively. Liver transplant recipients had lower pregnancy complications than kidney recipients whose rates for preeclampsia, C-section, and preterm delivery were 27%, 54%, and 46%, respectively. Liver transplant patients also had significantly greater delivery outcomes than kidney transplant recipients with the mean gestational age at 37 weeks versus 36 weeks, and infant birth weight at 6 pounds versus 5 pounds.

"Our findings confirm that pregnancy is feasible following liver transplantation, but not without potential complications," said Neha Deshpande, who conducted the literature review. "Women who wish to start families following a liver transplant should work closely with their physicians to minimize risk and to ensure a healthy outcome for themselves and their babies." The authors encourage transplant recipients to report pregnancy outcomes to transplantation centers for data collection.

In a related editorial, Dr. Vincent Armenti from Thomas Jefferson University in Philadelphia, Pa. writes, "Dr Segev and colleagues conclude that live birth outcomes are possible among liver transplant recipients and this favorable trend is consistent on the international level." He also encourages reporting to active registries to monitor pregnancy and births in patients following liver transplantation.

Provided byWiley

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June 7th, 2012

Scientists working to develop a urine test to identify patients at risk of liver cancer in Africa have received a huge boost after a scientific instrument manufacturer donated a mass spectrometer to laboratories in the Gambia.

The gift from Waters Corporation will allow the researchers to analyse samples from people with hepatitis B infection to identify chemical markers of cancer and liver fibrosis, which can be treated if detected early. Researchers from Imperial College London are among those who will be using the technology as part of a five-year, 3 million-euro research project that aims to reduce the incidence of liver cancer by treating chronic hepatitis B infection. This European Union-funded project, called PROLIFICA, involves institutions from six countries in Europe and Africa.

Hepatitis B is a viral infection transmitted through bodily fluids that attacks the liver. Despite being preventable with a vaccine, infection is endemic in sub-Saharan Africa and about one in four adults with chronic infection die of liver cancer or cirrhosis. Worldwide, an estimated 350 million people live with chronic infection and around 600,000 people die of its effects each year.

Preliminary studies have identified urinary biomarkers that might help doctors to detect cancer at an early stage when it is treatable, but more research is needed to validate these findings and make further progress towards developing a cheap and reliable diagnostic test.

The new machine is the first mass spectrometer installed in the region. It was unveiled on 28 May at a ceremony to mark its installation at the Medical Research Council (MRC) laboratories in the Gambia, attended by representatives from the country’s ministry of health. Aside from the PROLIFICA project, the donation by Waters will support the ongoing work of MRC scientists on bacterial disease, viral disease and malaria. In particular, the machine’s capability to identify biomarkers of disease will enhance the development of new methods to diagnose diseases early. This will help provide treatment to more patients and will particularly benefit the health of African children.

"We are very grateful for Waters’ kind donation,” said Professor Elaine Holmes, from the Department of Surgery and Cancer at Imperial, who travelled to the Gambia to train local researchers to use the mass spectrometer. “It opens up a whole host of new opportunities in research into infectious diseases, childhood illnesses, cancer and crucially in West Africa, into maternal and childhood nutrition."

Professor Simon Taylor-Robinson, from the Department of Medicine at Imperial, said: “The mass spectrometer will be enormously useful to our work towards developing a urinary dipstick for profiling patients with hepatitis B and preventing the progression to liver cancer. It will also enable us to leave a fantastic legacy in Africa, by building the capacity to undertake metabolic profiling studies locally. A number of our Imperial colleagues are keen to explore the potential applications in other diseases that are prevalent in the area, such as tuberculosis, childhood bacterial infections and the neglected tropical diseases.”

Provided by Imperial College London

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Drug diversion suspected in NH hepatitis C cases

By HOLLY RAMER

Associated Press / June 13, 2012

CONCORD, N.H. (AP) — An employee misusing drugs is the most likely cause of an outbreak of hepatitis C among patients who were treated at the Exeter Hospital’s cardiac catheterization lab, New Hampshire’s public health director said Wednesday.

‘‘Based on all the testing we've done, based on all the interviews we've performed with employees and with patients, the review of the hospital data — all of this information points toward drug diversion as the most plausible explanation,’’ Dr. Jose Montero said.

A total of 20 people, including a hospital worker, have been diagnosed with the same strain of the liver-destroying virus since the state began investigating the outbreak last month. Montero would not comment on the specific employee suspected of causing the outbreak or say whether law enforcement is involved, but he said drug diversion generally involves someone using a syringe to inject themselves with medication meant for patients and then re-using the syringe on patients.

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The ancient Korean mummy of a child provides clues to the hepatitis B virus genome. (Credit: Seoul National Univesity)

ScienceDaily (May 29, 2012) — The discovery of a mummified Korean child with relatively preserved organs enabled an Israeli-South Korean scientific team to conduct a genetic analysis on a liver biopsy which revealed a unique hepatitis B virus (HBV) genotype C2 sequence common in Southeast Asia.

Additional analysis of the ancient HBV genomes may be used as a model to study the evolution of chronic hepatitis B and help understand the spread of the virus, possibly from Africa to East-Asia. It also may shed further light on the migratory pathway of hepatitis B in the Far East from China and Japan to Korea as well as to other regions in Asia and Australia where it is a major cause of cirrhosis and liver cancer.

The reconstruction of the ancient hepatitis B virus genetic code is the oldest full viral genome described in the scientific literature to date. It was reported in the May 21 edition of the scientific journal Hepathology by a research team from the Hebrew University of Jerusalem's Koret School of Veterinary Medicine, the Robert H. Smith Faculty of Agriculture, Food and Environment; the Hebrew University's Faculty of Medicine, the Hadassah Medical Center's Liver Unit; Dankook University and Seoul National University in South Korea.

Carbon 14 tests of the clothing of the mummy suggests that the boy lived around the 16th century during the Korean Joseon Dynasty. The viral DNA sequences recovered from the liver biopsy enabled the scientists to map the entire ancient hepatitis B viral genome.

Using modern-day molecular genetic techniques, the researchers compared the ancient DNA sequences with contemporary viral genomes disclosing distinct differences. The changes in the genetic code are believed to result from spontaneous mutations and possibly environmental pressures during the virus evolutionary process. Based on the observed mutations rates over time, the analysis suggests that the reconstructed mummy's hepatitis B virus DNA had its origin between 3,000 to 100,000 years ago.

The hepatitis B virus is transmitted through the contact with infected body fluids , i.e. from carrier mothers to their babies, through sexual contact and intravenous drug abuse. According to the World Health Organization, there are over 400 million carriers of the virus worldwide, predominantly in Africa, China and South Korea, where up to 15 percent of the population are cariers of the virus. In recent years, universal immunization of newborns against hepatitis B in Israel and in South Korea has lead to a massive decline in the incidence of infection.

The findings are the result of a collaborative effort between Dr. Gila Kahila Bar-Gal of the Hebrew University of Jerusalem's Koret School of Veterinary Medicine; Prof. Daniel Shouval of the Hadassah Medical Center's Liver Unit and Hebrew University; Dr. Myeung Ju Kim of Dankook University, Seok Ju Seon Memorial Museum; Dr. Dong Hoon Shin of Seoul National University, College of Medicine ; Prof Mark Spigelman of the Hebrew University's Dept. of Parasitology and Dr. Paul R. Grant of University College of London,Dept. of Virology.

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