Tamiflu-Resistance Gene in H7N9 Bird Flu Spurs Drug Tests

[Pathfinder]

Tamiflu-Resistance Gene in H7N9 Bird Flu Spurs Drug Tests

By Kanoko Matsuyama & Jason Gale - 2013-04-11T05:08:42Z.

A gene mutation known to help influenza resist Tamiflu was found in the first of three H7N9 bird-flu patient specimens in China, sequence data show.

The flu virus from the patient in Shanghai has a mutation known as R292K that causes high-level resistance to the Roche Holding AG (ROG) pill and reduced sensitivity to a related drug from GlaxoSmithKline Plc (GSK) called Relenza, genetic sequence information posted on the website of the Global Initiative on Sharing Avian Influenza Data show. Subsequent H7N9 specimens from a patient in Shanghai and one in Anhui province don?t show the mutation.

The finding of the mutation warrants further analysis, said Masato Tashiro, a director at Japan?s National Institute of Infectious Diseases in Tokyo.

More...
http://www.bloomberg.com/news/2013-...e-gene-in-h7n9-bird-flu-spurs-drug-tests.html

 

[JJackson]

Re: Tamiflu-Resistance Gene in H7N9 Bird Flu Spurs Drug Tests

This is on Shanghai/1 at position 289 on the N9 alignment (position numbers vary slightly depending on sero-type). I have not been able to find anything specific on its effects on an N9 background but it can certainly produce resistance on other backgrounds and reduced fitness in ferrets - also on other Ns).
This is the most relevant paper (with open access) I found. If anyone has anything better please post.

 

[Catbird]

Re: Tamiflu-Resistance Gene in H7N9 Bird Flu Spurs Drug Tests

Saw a tweet that mentions an interesting article on this situation in regards to H5N1.

"Why Meat in China ? and the U.S. ? Has a Drug Problem

Feb. 12, 2013

...Chinese chicken farmers had an unfortunate habit of prophylactically dosing their birds with Tamiflu, the only antiviral drug that showed any effectiveness against H5N1. (U.S. preparations for a possible bird-flu pandemic included stockpiling millions of doses of the drug.) As a result, it became that much more difficult for health officials to track H5N1 outbreaks because Tamiflu-dosed chickens could still get infected and spread the virus but without showing the symptoms that would set off medical alarm bells. And overusing Tamiflu also eroded its effectiveness as over time the H5N1 virus was able to develop a resistance to the drug. Had an H5N1 human pandemic ever occurred, we may well have been helpless...".

xhttp://science.time.com/2013/02/12/why-meat-in-china-and-the-u-s-has-a-drug-problem/

 

[JimO]

Re: Tamiflu-Resistance Gene in H7N9 Bird Flu Spurs Drug Tests

Preventative use of Tamiflu on chickens? I would think that would be too expensive. But, if true, that is not good news.

 

[Labrador - Sadie]

Re: Tamiflu-Resistance Gene in H7N9 Bird Flu Spurs Drug Tests

http://www.bloomberg.com/news/2013-05-28/new-bird-flu-found-to-be-resistant-to-roche-s-tamiflu-in-study.html


New Bird Flu Found to Be Resistant to Roche’s Tamiflu Drug

A gene mutation known to make flu viruses resistant to Roche Holding AG (ROG)’s Tamiflu was identified in two patients infected with the H7N9 bird flu virus in China, a study found.

The gene was discovered in two of three patients who became the most severely ill in a study of 14 patients treated with Tamiflu after being admitted to a Shanghai hospital in April with H7N9 infection, according to an article published in The Lancet medical journal today. In one patient, the resistance developed after the initial infection, suggesting treatment with Tamiflu may have spurred the..............

 

[NS1]

Re: Tamiflu-Resistance Gene in H7N9 Bird Flu Spurs Drug Tests

Fatalities
Associated With
TamiFlu Resistance
via
NA 292K​

Of the 5 sequences representing 4 human cases that carry the NA 292K polymorphism, 2 fatalities have occurred, both in Shanghai. At least 3 of the 4 cases required treatment involving in extremis measures such as ECMO.

Today's publication in The Lancet from Dr. Malik Peiris and an extensive multi-disciplinary team of Chinese organisations defines clinical progressions, treatments, outcomes and experimental findings including discussions on two TamiFlu Resistance markers, NA 292K and NA 152K. Their initial study reveals that the single 292K polymorphism increases oseltamivir resistance 100 fold.

www.thelancet.com Published online May 28, 2013 http://dx.doi.org/10.1016/S0140-6736(13)61125-3
Association between adverse clinical outcome in human disease caused by novel influenza A H7N9 virus and sustained viral shedding and emergence of antiviral resistance

We have shown that A/Shanghai/1/2013 (H7N9) virus isolate contains a mixed population of Arg/Lys at position 292 of the NA gene, and by purifying virus plaques that carry NA Arg292 and Lys292, we have noted that this mutation increases resistance to oseltamivir by 100-fold and zanamivir by 30-fold in a fluorescence-based NA inhibition assay (unpublished data).

In patient 6 (from the mechanical ventilation group), we found emergence of Arg152Lys mutation in the NA gene. This mutation was first reported from an
immunocompromised patient infected with influenza B after zanamivir treatment.13 Using the baculovirus expressed N9 NA protein, it had been shown to exhibit mild resistance to both zanamivir and oseltamivir in vitro.14

We have been concerned that the few detailed clinical progressions may not have fully reported sepsis. This paper provides insight confirming one type of clinical similarity to other zoonotics including many pH1N1 cases and H5N1 human infections:

We detected viral RNA in the serum obtained at some time during the clinical illness of 12 (86%) of the 14 patients (appendix; all three patients in the ECMO group, all four patients in the mechanical ventilation group, and five of seven patients in the pneumonia group).

 

[NS1]

Re: Tamiflu-Resistance Gene in H7N9 Bird Flu Spurs Drug Tests

This thread has moved

Almost all patients responded to oseltamivir treatment.

In some ECMO patients, and / or under corticosteroids treatment, R292K mutation in the NA happened, despite initial viral suppression.

During the course of treatment, a viral load 'rebound' was observed and it was suggested that either the immune status of patient or the concurrent use of steroids made the emersion of R292K much easy than in other patients.

Mixed population of susceptible and resistant to oseltamivir H7N9 viruses in certain cases has been noted from ALL the WHO updates so far.

Since the old age of the patients and the severity of the disease in these cases, this represents an expected finding as happened for H5N1 cases in the past.

Functional antivirals tests performed on R292K isolates demonstrated they are susceptible to oseltamivir and zanamivir albeit with some degree of variability.

It should be used a combination therapy in order to safeguard the limited arsenal of antivirals currently available for treatment and for pandemic preparedness stockpile.

An expedited clinical testing of such combinations should be performed as soon as possible in addition to an enhance surveillance for resistant strain in human and animals.

GM

Almost all Influenza cases self-resolve without treatment of any kind (~99.1 to 99.4%).

We can hardly nominate this situation as a clinical success when a substance designed to prevent the release of viral RNA from human cells preceded a finding of viral RNA in the blood from 86% (12 of 14) of professionally-treated patients. As you may recall, virus in the blood is a rarity in human influenza infections and is a direct indicator of increased morbidity. The entire cohort of 14 patients was treated aggressively with oseltamivir.

A 100 fold reduction in inhibition due to the NA 292K is no minor matter when 5-fold increase in IC50 is a traditional boundary for gathering statistics. Drug resistance was recorded as early as 4 days after treatment initiation.

Table 1: Demographic details, therapy, and outcome of patients with A/H7N9 infection appears to indicate that multi-drug antiviral therapy contributed at this time to only 1 successful discharge (Patient 8 at 22 days) with 1 remaining under standard treatment (Patient 5 at 37 days) and with 1 remaining on ECMO (Patient 3 at 46 days) at the time of data gathering. One death has also occurred after multi-drug treatment (Patient 2 at 19 days).

Ergo, at the time of data gathering, the "Released versus Deceased" counts are equal for this cohort (1/1) . . . demonstrating something much less than a stellar summary.

Despite the continual applause at these self-declared victories, the actual data predicts a future catastrophic clinical failing (even where logistics allow heroic measures) should emergent H7N9 transmission increase . . .

We would like to see an emergence of transparency in China by their reporting all of the current cases before the world is faced with a simultaneous emergence of H7N9 pathogen on all populated continents.

Their publication concerning the Beijing case is a start. Now let's put all the data on the table so that strategies may be developed that show potential for success.

 

[NS1]

Re: Tamiflu-Resistance Gene in H7N9 Bird Flu Spurs Drug Tests

This thread has moved

I completely disagree with this perspective.

ECMO patients are quite critical and their outcome is often fatal, taking into account the advanced age and co-morbidities.

Clearly the medical countermeasures arsenal is not enough to cope with a major outbreak but this should emphasize the need for an expedited trial for combined therapy even with M2 ion channel inhibitors (since their possible synergistic effect when combined with NAIs) or ribavirin.

Other avenues should be explored such as use of IVIG, COX-2 inhibitors, statins and other phase-3 investigational antivirals.

Treatment protocols for influenza remain insufficient to date, despite sixteen years after the initial H5N1 scare.

In several instances, researchers called for such revised therapeutical protocols, with the inclusion of other antiviral agents and immunomodulators.

Unfortunately, the stance of some intl agencies toward oseltamivir may have prevented the development of better combination of drugs in severe influenza cases.

'Catastrophic' should not be in the scientist vocabulary and surely not in the communication effort for a better understanding of current events and in the quest for a solution.

We cannot predict the future and it is not our mandate to scare Readers.

Not need to say that - obviously - all people are free to tell their thoughts. GM

And how did the patients get to the ECMO heroic effort . . . by failing to improve under all other interventions attempted. Of course, they are in bad shape at that stage.

Language matters. Word selection matters. A forum is intended to inform.

If those with the data are dissuaded from displaying the facts because the facts are difficult to manage in this managed media environment, then we will all continue in the same failed programs. And those failed percentages are substantial.

If each of these recommended intervention items is known to be insufficient and several are genetically contra-indicated, including M2 ion, where is the logic that using completely untested combinations of items that fail individually will lead to beneficial outcomes? Does some reason exist that the citizens should extend deeper trust to those who have had ample opportunity and continually failed for 16 years? How much longer are we to wait before this process of accumulating sub-optimisations will randomly produce the grand solution?

Science should not be driven by off-label accumulation of sub-optimal solutions in the hope of optimising. Hope is not a plan . . . even in a crisis, hope is not a plan. Does a tornado generate an organised outcome or will we be facing a great deal of wind, noise and disarray? This idea of round-robin, treatment protocol aggregation sounds like the foundation for a somewhat less-than-thoughtful, grand-scale human experimentation led by those who have previously exercised poor discipline, displayed limited planning and demonstrated weak execution.

We agree that 16 years is a long time to rely on a solution that is known to fail. Now are we being asked to rely on those same business leaders and those same public health officials that held citizens to this failure prone solution while consuming 16 years of revenue. Thousands of unnecessary deaths occurred from H5N1 and pH1N1.

We're not certain why everyone in Influenza research continues to say that we can't predict the future? We can predict the future. Carefully cataloging observational cause and effect leads to selection of desired outcomes over undesired outcomes. A catastrophic outcome occurs when these clinical findings employing well-tested primary strategy anti-virals are scaled to the international level using standard Clinical Attack Rates coupled with the outcome percentages of these cases.

Rigorous mathematics is not required to understand the sheer numbers. A failure rate of 18% translates to many millions dying if this strain becomes pandemic.

Those types of numbers are catastrophic regardless of present feelings about danger, fear, psychology, public perception or media management of ongoing clinical failures in the treatment of fulminant zoonotic Influenza.

 

[Vibrant62]

Re: Tamiflu-Resistance Gene in H7N9 Bird Flu Spurs Drug Tests

It is clear that governments the world over need to be investing heavily both in terms of time and money to find beneficial solutions and interventions for H7N9.

They need to be looking at our options right now for the short term, as well as the longer term emphasis on a Universal Vaccine and novel antiviral drugs - both of which need to be continued as a primary research focus. Neither of these options are likely to be close to being delivered if an H7N9 pandemic strikes in the next few months or years.

If an H5N1 pandemic is currently considered by leading scientists working in this field to be a 'when not if' event, then an H7N9 pandemic must be considered as a 'how soon' certainty in view of its greater degree of human adaptation and all the uncomfortable data we are currently being presented with.

As the threat is immediate and the basic 'weapons' we have at our disposal are severely lacking in terms of their deliverability and efficacy, we need the powers that be to open their minds to look at interim solutions that could help mitigate such a pandemic whilst other pharmaceutical options are developed; we dont have time to wait.

To summarise:-
a) vaccine manufacturing capacity is still subject to the problems experienced in the H1N1 2009 pandemic. The first and second waves of any pandemic virus are likely to have been and gone before vaccines can be delivered in any meaningful quantites. This is aside and apart from the issues created by the low immunogenicity of the H7 protein.

b) based on the available data, it appears that an H7N9 pandemic is likely to be resistant to tamiflu at outbreak or very shortly thereafter.

So what do we know about that is currently available and could have some beneficial effects?

There is data that supports positive benefits of basic things such as Vitamin C, Zinc, Vitamin D which need thorough testing to see if there is a mitigating effect in the case of H7N9 individually and in combination.

See (as a small representative sample of the currently available data):-

Zinc 'keeps immune system in check'

Vitamin C Is an Essential Factor on the Anti-viral Immune Responses through the Production of Interferon-α/β at the Initial Stage of Influenza A Virus (H3N2) Infection

Clin Infect Dis. Low Serum 25-hydroxyvitamin D Level and Risk of Upper Respiratory Tract Infection in Children and Adolescents

Low vitamin D levels a risk factor for pneumonia

Such interventions could be widely applied globally and individuals could self medicate and self purchase. However governments and health authorities want to see additional data and research (ferret trials, human trials) before making any recommendations for interventions like this. The problem is that this data simply does not exist at this time (proving the case one way or the other) because:-

i) these are not patentable entities
ii) producing/ manufacturing companies of these non-patentable products simply do not have access to anything close to the level of funding or internal resources as pharmaceutical companies and
iii) pharmaceutical companies would not carry out this research as these are non-patentable interventions. How can any company invest tens of millions in research when they may have no control over the findings nor reap the benefits for thier shareholders via global use of a specific product? They cant.

That leaves non-pharmacological measures such as social distancing, quarantines, school closures etc. However, H5N1 modelling has shown that society cannot function if these measures are applied too aggressively; critical infrastructure must be maintained; economies and social stability must be maintained.

Even if more detailed research found that the benefits of the type of interventions highlighted above were limited but still positive (i.e they would be no panacea) such interventions would at least self empower individuals in their own health protection if there is data to support their use.

In other words, the market driven model (which depends on rapid commercial funding and development for new interventions) simply does not work in these circumstances and governments and health authorities need to 'bite the bullet' and think outside the standard pharmaceutical paradigm to find the money and secure the research time to properly test these options which at least could be rapidly deployed globally and made widely available to populations in every nation.

Some benefit would be better than nothing at all, and may help to buy time whilst better long term solutions are developed.

 

[sharon sanders]

Re: Tamiflu-Resistance Gene in H7N9 Bird Flu Spurs Drug Tests

I have moved 2 posts to the archives that were irrelevant to the topic of this thread.

 

[Giuseppe]

Re: Tamiflu-Resistance Gene in H7N9 Bird Flu Spurs Drug Tests

bump this

 

[mixin]

Re: Tamiflu-Resistance Gene in H7N9 Bird Flu Spurs Drug Tests

Giuseppe,
I hope you will leave them. I think the points you make are worth considering.

When we are so limited, thinking outside the box or off-label uses may be the only chance to save lives.

 

[NS1]

Re: Tamiflu-Resistance Gene in H7N9 Bird Flu Spurs Drug Tests

TamiFlu Resistance
via
NA 292K​

Originally published on 2013-05-31-06:24 at China - H7N9 Human Isolates on Deposit at GISAID [thread].

www.thelancet.com Published online May 28, 2013 http://dx.doi.org/10.1016/S0140-6736(13)61125-3
Association between adverse clinical outcome in human disease caused by novel influenza A H7N9 virus and sustained viral shedding and emergence of antiviral resistance

Four of the fourteen Sanger Neuraminidase sequences deposited at GenBank by Fudan University today and associated with the 2013-05-28 AntiViral Resistance paper (Malik Peiris and associates, The Lancet) show NA 292K. Two patients were indicated in the paper as developing antiviral resistance at NA 292K.

We are grateful to Dr. Peiris for coordinating production of the cross-reference information with the authoring organisations concerning serialisation and patient assignment for the samplings.

NA 292K

Our preliminary groupings for the four genotypic AntiViral Resistant sequences are estimated until we receive the master cross-reference. These groups represent either patient 2 or patient 3 from the tables in the paper. ECMO was required for each. Patient 2 expired at 19 days post-onset; patient 3 remained under treatment at 46 days (as of May 18, 2013). Group 1 is very likely Patient 2 who died during ECMO treatment. At least one fatality is represented in these 2 groupings.

We have arranged Group 1 due to Hemagglutinin homology:

Group 1 with 3 Sequences
Probable as Patient 2 Fatality
Drug Resistance by Treatment Day 4

• ChinaShanghai5240T_88M_2013_04_25_TmX_f [KF028381]
• ChinaShanghai5180T_88M_2013_04_23_TmX_f [KF028380]
• ChinaShanghai5083T_88M_2013_04_20_TmX_f [KF028379]

Group 2 with 1 Sequence
Probable as Patient 3

• ChinaShanghai4842T_56M_2013_04_13_TmX_s [KF028383]

NA Polymorphism Summary

ChinaShanghai4798T_62M_2013_04_12_TmX_s [KF028387] shows 152K and is likely Patient 6 who was mechanically ventilated and successfully discharged 35 days from onset. The polymorphism developed after day 3 of oseltamivir treatment and by the sampling date on day 5 of treatment.

ChinaShanghai4821T_2013_04_12_s [KF028392] shows NA 285K [284K] with first and third base polymorphisms. Only the emergent H7N9 ChinaShanghai4664T_2013_03_05 [KC853231] and a single instance from H4N9 avian show this polymorphism in the data record.

HA Polymorphism Summary

Three HA sequences carry a synonymous change at the third base of aa471 producing syn471E (GAg) [syn462E (GAg)]:

Probable as Patient 2 Fatality

• ChinaShanghai5240T_88M_2013_04_25_TmX_f [KF028376]
• ChinaShanghai5180T_88M_2013_04_23_TmX_f [KF028375]
• ChinaShanghai5083T_88M_2013_04_20_TmX_f [KF028374]

All three are also TamiFlu Resistant and are from a patient that required ECMO.

This syn462E (GAg) polymorphism has been seen in non-emergent H7N9 and in 5 emergent Human H7N9 sequences, including 3 from the single Taiwan case and 2 from the Pasteur Shanghai GISAID deposit of preliminary sequences on 2013-05-23.

The revision is also found in Pandemic H1N1 2009 (pH1N1), H5N1 (wildtype), H7N3 (extensive), H7N7 (rare, passerine), H9N2 (extensive, ostrich) and H9N9. Four of the nine instances within pH1N1 (all host transition from 2009) are from China and three others are from neighboring Asian countries. Argentina shows 2 sequences from subjects aged 2 years and younger. Seven of the eight pH1N1 sequences with this polymorphism and age metadata are pediatric cases and one of those Chinese sequences was published as part of a drug resistance investigation.

Additional Reading on Emergent H7N9 Genetics

We acknowledge the authors, originating and submitting laboratories of the sequences from GenBank & from GISAID’s EpiFlu™ Database on which this research is based. An additional list is detailed in the linked PDF entitled "GISAID_Citations_H5N1_2011" at Is H7N9 Spreading from Human to Human in China? Post#164

GISAID Citations

• GeneWurx Cross Serotype Homology Analysis, Open-Access, Full-Text version
• Human Emergent H7N9 from Zhejiang Province
• Environment Emergent H7N9 from Zhejiang
• Fatal H5N1 Homology to Emergent H7N9 from Shanghai in March
• Fatal H5N1 Karo Cluster Homology to Emergent H7N9 from First Fujian Case
• Receptor Binding Site Novelty from First Taiwan H7N9 Case
• China - H7N9 Human Isolates on Deposit at GISAID, Comprehensive Genetics Discussion