Hi @nick0912,
This has been answered in a recent post by @john.tavis:
Cheers,
Thomas
1 Like
Is anyone but me worried that the pharmaceutical industry may stand in the way of finding a cure for hepatitis B? They surely have more money to make by people taking medication every day indefinitely than they’d make if hep b patients were all cured.
Dear @Barry,
Your concern is valid in that pharmaceutical companies stand to make more money from a drug that people have to take forever than from a drug which can provide a cure with a finite course of therapy. However, it is important to understand that we already have this situation well developed in HBV with drugs that directly target viral replication like ETV, TDF and TAF. The first two have already become much more cheaply available as generic medications as the patents protecting these medications have already expired. This makes it very unattractive for companies to develop new medications which cannot improve on the performance already achieved by these medications.
Importantly, these three medications, while effective at halting the progression of liver disease and controlling viral replication, have not done a good job at controlling the death rates from HBV infection. In fact the most recent data show that global death rates from HBV are unfortunately increasing. This is due in part to guidelines restricting the introduction of these medications earlier on in the disease and ageing of the patient population but also because of an important deficiency in these medications: they cannot remove the infection from the liver.
As such, there is a real drive in the industry to develop new medications, most of which are focused on targeting restoration of immune control of the virus (by targeting HBsAg) so that therapy is no longer required. With this scenario achieved (we call this functional cure) only a very tiny but dormant trace of viral infection is present and is persistently dormant in the absence of therapy. These new therapies by definition will all have to be finite in nature and have the promise of better long term outcomes for patients without the need for therapy.
Best regards.
5 Likes
Hello,
I’m totally ignorant about it… but I just came across this article and wanted to ask @ThomasTu and @john.tavis what do you think? could this be used in HBVDNA?
New algorithm finds lots of gene-editing
enzymes in environmental DNA**
CRISPR—Clustered Regularly Interspaced Short Palindromic
Repeats—is the microbial world’s answer to adaptive immunity.
Bacteria don’t generate antibodies when they are invaded by a
pathogen and then hold those antibodies in abeyance in case
they encounter that same pathogen again, the way we do.
Instead, they incorporate some of the pathogen’s DNA into their
own genome and link it to an enzyme that can use it to
recognize that pathogenic DNA sequence and cut it to pieces if
the pathogen ever turns up again.The enzyme that does the
cutting is called Cas, for CRISPR associated. Although the
CRISPR-Cas system evolved as a bacterial defense mechanism,
it has been harnessed and adapted by researchers as a
powerful tool for genetic manipulation in laboratory studies. It
also has demonstrated agricultural uses, and the first CRISPR-
based therapy was just approved in the UK to treat sickle-cell
disease and transfusion-dependent beta-thalassemia.
Now, researchers have developed a new way to search
genomes for CRISPR-Cas-like systems. And they’ve found thatwe may have a lot of additional tools to work with.Modifying
DNA
To date, six types of CRISPR-Cas systems have been identified in
various microbes. Although they differ in detail, they all have the
same appeal: They deliver proteins to a given sequence of
genetic material with a degree of specificity that has heretofore
been technically difficult, expensive, and time-consuming to
achieve. Any DNA sequence of interest can be programmed
into the system and targeted.
The native systems found in microbes usually bring a nuclease—
a DNA-cleaving enzyme—to the sequence, to chop up the
genetic material of a pathogen. This ability to cut any chosen
DNA sequence can be used for gene editing; in tandem with
other enzymes and/or DNA sequences, it can be used to insert
or delete additional short sequences, correcting mutant genes.
Some CRISPR-Cas systems cleave specific RNA molecules
instead of DNA. These can be used to eliminate pathogenic
RNA, like the genomes of some viruses, the way they are
eliminated in their native bacteria. This can also be used to
rescue defects in RNA processing.
But there are lots of additional ways to modify nucleic acids that
might be useful. And it’s an open question as to whether
enzymes that perform additional modifications have evolved.
So, some researchers decided to search for them.Researchers at MIT developed a new tool to detect variable
CRISPR arrays and applied it to 8.8 tera (1012)-base pairs of
prokaryotic genomic information. Many of the systems they
found are rare and only appeared in the dataset in the past 10
years, highlighting how important it is to continue adding
environmental samples that were previously hard to attain into
these data repositories.The new tool was required because
databases of protein and nucleic acid sequences are expanding
at a ridiculous rate, so the techniques for analyzing all of that
data need to keep up. Some algorithms that are used to analyze
them try to compare every sequence to every other one, which
is obviously untenable when dealing with billions of genes.
Others rely on clustering, but these find only genes that are
highly similar so they can’t really shed light on the evolutionary
relationships between distantly related proteins. But fast locality-
sensitive hashtag-based clustering (“flash clust”) works by
binning billions of proteins into fewer, larger clusters of
sequences that differ slightly to identify new, rare relatives.
The search using FLSHclust successfully pulled out 188 new
CRISPR-Cas systems.
Lots of CRISPyness
A few themes emerged from the work. One is that some of the
newly identified CRISPR systems use Cas enzymes with never-
before-seen domains, or appear to be fusions with knowngenes. The scientists further characterized some of these and
found one to be more specific than the CRISPR enzymes
currently in use, and another that cuts RNA that they propose is
structurally distinct enough to comprise an entirely new seventh
type of CRISPR-Cas system.
A corollary of this theme is the linkage of enzymes with different
functionalities, not just nucleases (enzymes that cut DNA and
RNA), with CRISPR arrays. Scientists have harnessed CRISPR’s
remarkable gene-targeting ability by linking it to other kinds of
enzymes and molecules, like fluorescent dyes. But evolution
obviously got there first.
As one example, FLSHclust identified something called a
transposase associated with two different types of CRISPR
systems. A transposase is an enzyme that helps a particular
stretch of DNA jump to another part of the genome. CRISPR
RNA-guided transposition has been seen before, but this is
another example of it. A whole host of proteins with varying
functions, like proteins with transmembrane domains and
signaling molecules, were found linked to CRISPR arrays,
highlighting the mix-n-match nature of the evolution of these
systems. They even found a protein expressed by a virus that
binds to CRISPR arrays and renders them inactive—essentially,
the virus inactivates the CRISPR system that evolved to protect
against viruses.Not only did the researchers find novel proteins
associated with CRISPR arrays, but they also found otherregularly interspaced repeat arrays that were not associated
with any cas enzymes—similar to CRISPR but not CRISPR. They’re
not sure what the functionality of these RNA guided systems
might be but speculate that they are involved in defense just like
CRISPR is.
The authors set out to find “a catalog of RNA-guided proteins
that expand our understanding of the biology and evolution of
these systems and provide a starting point for the development
of new biotechnologies." It seems they achieved their goal:
“The results of this work reveal unprecedented organizational
and functional flexibility and modularity of CRISPR systems,”
they write. They go on to conclude: “This represents only a small
fraction of the discovered systems, but it illuminates the
vastness and untapped potential of Earth’s biodiversity, and the
remaining candidates will serve as a resource for future
exploration.” New algorithm finds lots of gene-editing
enzymes in environmental DNA
CRISPR—Clustered Regularly Interspaced Short Palindromic
Repeats—is the microbial world’s answer to adaptive immunity.
Bacteria don’t generate antibodies when they are invaded by a
pathogen and then hold those antibodies in abeyance in case
they encounter that same pathogen again, the way we do.
Instead, they incorporate some of the pathogen’s DNA into their
own genome and link it to an enzyme that can use it to
recognize that pathogenic DNA sequence and cut it to pieces if
the pathogen ever turns up again.The enzyme that does the
cutting is called Cas, for CRISPR associated. Although the
CRISPR-Cas system evolved as a bacterial defense mechanism,
it has been harnessed and adapted by researchers as a
powerful tool for genetic manipulation in laboratory studies. It
also has demonstrated agricultural uses, and the first CRISPR-
based therapy was just approved in the UK to treat sickle-cell
disease and transfusion-dependent beta-thalassemia.
Now, researchers have developed a new way to search
genomes for CRISPR-Cas-like systems. And they’ve found thatwe may have a lot of additional tools to work with.Modifying
DNA
To date, six types of CRISPR-Cas systems have been identified in
various microbes. Although they differ in detail, they all have the
same appeal: They deliver proteins to a given sequence of
genetic material with a degree of specificity that has heretofore
been technically difficult, expensive, and time-consuming to
achieve. Any DNA sequence of interest can be programmed
into the system and targeted.
The native systems found in microbes usually bring a nuclease—
a DNA-cleaving enzyme—to the sequence, to chop up the
genetic material of a pathogen. This ability to cut any chosen
DNA sequence can be used for gene editing; in tandem with
other enzymes and/or DNA sequences, it can be used to insert
or delete additional short sequences, correcting mutant genes.
Some CRISPR-Cas systems cleave specific RNA molecules
instead of DNA. These can be used to eliminate pathogenic
RNA, like the genomes of some viruses, the way they are
eliminated in their native bacteria. This can also be used to
rescue defects in RNA processing.
But there are lots of additional ways to modify nucleic acids that
might be useful. And it’s an open question as to whether
enzymes that perform additional modifications have evolved.
So, some researchers decided to search for them.Researchers at MIT developed a new tool to detect variable
CRISPR arrays and applied it to 8.8 tera (1012)-base pairs of
prokaryotic genomic information. Many of the systems they
found are rare and only appeared in the dataset in the past 10
years, highlighting how important it is to continue adding
environmental samples that were previously hard to attain into
these data repositories.The new tool was required because
databases of protein and nucleic acid sequences are expanding
at a ridiculous rate, so the techniques for analyzing all of that
data need to keep up. Some algorithms that are used to analyze
them try to compare every sequence to every other one, which
is obviously untenable when dealing with billions of genes.
Others rely on clustering, but these find only genes that are
highly similar so they can’t really shed light on the evolutionary
relationships between distantly related proteins. But fast locality-
sensitive hashtag-based clustering (“flash clust”) works by
binning billions of proteins into fewer, larger clusters of
sequences that differ slightly to identify new, rare relatives.
The search using FLSHclust successfully pulled out 188 new
CRISPR-Cas systems.
Lots of CRISPyness
A few themes emerged from the work. One is that some of the
newly identified CRISPR systems use Cas enzymes with never-
before-seen domains, or appear to be fusions with knowngenes. The scientists further characterized some of these and
found one to be more specific than the CRISPR enzymes
currently in use, and another that cuts RNA that they propose is
structurally distinct enough to comprise an entirely new seventh
type of CRISPR-Cas system.
A corollary of this theme is the linkage of enzymes with different
functionalities, not just nucleases (enzymes that cut DNA and
RNA), with CRISPR arrays. Scientists have harnessed CRISPR’s
remarkable gene-targeting ability by linking it to other kinds of
enzymes and molecules, like fluorescent dyes. But evolution
obviously got there first.
As one example, FLSHclust identified something called a
transposase associated with two different types of CRISPR
systems. A transposase is an enzyme that helps a particular
stretch of DNA jump to another part of the genome. CRISPR
RNA-guided transposition has been seen before, but this is
another example of it. A whole host of proteins with varying
functions, like proteins with transmembrane domains and
signaling molecules, were found linked to CRISPR arrays,
highlighting the mix-n-match nature of the evolution of these
systems. They even found a protein expressed by a virus that
binds to CRISPR arrays and renders them inactive—essentially,
the virus inactivates the CRISPR system that evolved to protect
against viruses.Not only did the researchers find novel proteins
associated with CRISPR arrays, but they also found otherregularly interspaced repeat arrays that were not associated
with any cas enzymes—similar to CRISPR but not CRISPR. They’re
not sure what the functionality of these RNA guided systems
might be but speculate that they are involved in defense just like
CRISPR is.
The authors set out to find “a catalog of RNA-guided proteins
that expand our understanding of the biology and evolution of
these systems and provide a starting point for the development
of new biotechnologies." It seems they achieved their goal:
“The results of this work reveal unprecedented organizational
and functional flexibility and modularity of CRISPR systems,”
they write. They go on to conclude: “This represents only a small
fraction of the discovered systems, but it illuminates the
vastness and untapped potential of Earth’s biodiversity, and the
remaining candidates will serve as a resource for future
exploration.”
Hi @Gregory,
Yes, CRISPR has been used in many instances to try to target HBV and get rid of the virus DNA in the liver. In general, this has not been highly effective because there is just so much virus in the liver and this can target at most 90% of the virus. If there’s even one copy left over, then there is a chance that the virus infection just restarts itself. One of the issues has been getting the CRISPR into all the infected liver cells. Another issue is that you’re essentially breaking the DNA genomes, which can lead to all sorts of things happening (like precancerous mutations)
This may be a way to reduce the amount of virus in the liver in the far future, but in its current form, it may be at best an additional adjunct to a combination therapy.
Thomas
Hi @Gregory,
Thomas covered the applicability of this to HBV very well, so I’ll just commenton the biology of these gene editing mechanisms. They are part of the bacterial “immune systems” to protect the cells against invading DNA (transposons on plasmids acquired by conjugation, bacterial viruses). They were discovered only relatively recently, and I think that they are biologically exceptionally cool! Note that it is statistically certain that a huge diversity of such mechanisms exist, most of which are unknown adn some which are not CRISPR-related, in bacteria. The amount we don’t know about bacterial metabolism, genetics, and self-defense mechanisms vastly exceeds what we do know. There will undoubtedly be more discoveries of similar massive “coolness”, some of which will have medical implications.
John.
2 Likes
In addition to John’s comment, the search for new enzymes like this may still discover new molecular tools to target HBV in completely novel ways. So I don’t mean to be a dampener on this work, but what we have at the moment has not be terribly promising.
Thomas
Hello Dr. @ThomasTu @availlant @john.tavis
I just came across this article dated 1/11/2024 and was wondering if you have heard of it ( it’s from San Raffaelle hospital in Milan) the scientists involved are Dr. Matteo Iannacone and Dr. Luca Guidotti. I understand its a preclinical model but it sounds promising.
Latest news
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For the first time in the world, an immunotherapy capable of combating chronic hepatitis B has been tested on preclinical models
01/11/2024
Immunotherapy could also prove to be an effective solution for the treatment of chronic hepatitis B, which afflicts over 300 million people worldwide and is among the primary risk factors for liver cirrhosis and liver cancer. In fact, it seems that interleukin-2 (Il2) is able to reactivate the immune system of the HBV virus infection, which normally becomes chronic precisely because the body’s defenses are unable to eradicate the virus, which continues to survive and reproduce. inside the liver cells.
The first tests in the world on the molecule were conducted on preclinical models by a group of researchers from the Irccs San Raffaele hospital in Milan and the Vita-Salute San Raffaele university, in collaboration with the American start-up Asher Biotherapeutics. The results are published in Science Translational Medicine.
Existing therapies
The hepatitis B virus – they recall from San Raffaele – is transmitted by contact with infected blood, sexually or from mother to child during childbirth. Unlike what happens when an adult contracts the virus, over 90% of children infected at birth develop the chronic form of hepatitis B. Today there is a preventive vaccine against the infection, but patients who have already contracted it do not have it can benefit.
The turning point
For them, a possible turning point comes from the study coordinated by Matteo Iannacone, director of the Division of Immunology, Transplants and Infectious Diseases of the Irccs San Raffaele hospital, who returned to Italy after a long experience in the United States thanks to the Career Development Award of the Armenise-Harvard Foundation . Iannacone’s research, in synergy with the unit directed by Luca Guidotti, deputy scientific director of San Raffaele, has contributed in recent years to developing some of the antivirals commonly used to treat hepatitis B in its chronic form.
Previous research
Already in 2019, with some data published in Nature, through a molecular analysis carried out thanks to intravital microscopy techniques, scholars had demonstrated that T lymphocytes are unable to eradicate Hbv infection and are dysfunctional since their activation. The characterization of dysfunctional T lymphocytes had also allowed the San Raffaele researchers to identify the most suitable and effective molecules for reawakening these cells.
The role of IL2
One is interleukin-2, a messenger molecule of the immune system, which acts as a sort of immunotherapy and has already been successfully tested both in cultured cells obtained from patient samples and in animal models. However, Il-2, when administered systemically, produces serious side effects, increasing the permeability of blood vessels and causing severe edema. This happens because the molecule not only acts on T lymphocytes, but also on Natural killer cells that induce toxicity, as well as on regulatory cells that inhibit the immune response. The new study bypasses these obstacles.
“cis-targeting”
The results just published in the journal Science Translational Medicine add a piece to those published in 2019. Thanks to the collaboration with the company Asher Biotherapeutics which produces interleukin-2, the researchers managed to experiment with this molecule, developing an approach called " cis-targeting”. That is, interleukin-2, conjugated with a specific antibody, is able to target only T lymphocytes, activating them correctly against the disease.
Open road to immunotherapy
“We have seen in mouse models of the disease that, by administering this type of immunotherapy, the T lymphocytes expand in number and increase their function, i.e. they release cytokines capable of inhibiting viral replication and eliminate the infected cells, effectively killing the virus ”, comments Iannacone.
The results have therefore demonstrated, in preclinical models of hepatitis B and in the blood of healthy people, the safety, low toxicity and therapeutic efficacy of this innovative approach. “In addition to antiviral approaches, it is possible to finally think about an immunotherapy strategy. The next step is to test this approach on humans, in combination with antivirals,” concludes the researcher.
The research was supported by the European Research Council (ERC), the Airc Foundation for cancer research, the Ministry of Health and the Ministry of University and Research.
Source: aboutpharma.com
1 Like
Yes, we are familiar with this work. It is quite promising.
Luca has been a colleague and friend for over 25 years. He is a truly outstanding scientist and is one of the leading immunologists in the world studying HBV. The HBV research community voted to award him the annual Distinguished Award in Hepatitis B Research in 2023 in recognition of his outstanding achievements.
2 Likes
Dear @Gregory ,
I completely agree with John, Dr. Guidotti is a very well respected colleague in the field and the data from this preclinical study are interesting.
That being said, the preclincial models for HBV we currently have historically done and continue to do a poor job of predicting clinical performance in human patients or their potential to achieve functional cure with immmunological agents or agents designed to target HBsAg production (siRNA and ASO). In the case of NAPs, these compounds are the only agents which can achieve high rates of HBsAg loss and functional cure and yet they have NO antiviral activity in all in any of the standard preclinical models currently available.
This is not to say that the immnuological approach discussed by Dr. Giudotti is not valid or will fail, but that patients should not take hope before we see real safety and efficacy data in patients who have chronic HBV infection.
2 Likes
Thanks you @availlant and @john.tavis for always taking the time to answer 
hopeful patients
1 Like
Hi @Gregory,
I agree with both @availlant and @john.tavis about this work and the scientists involved in it.
I’m wondering if Matteo Iannacone (@mat who is the senior author involved) has any additional comments regarding the pre-clinical model, how it relates to patients, and where he hopes the research will lead in the upcoming years.
Cheers,
Thomas
2 Likes
Which drugs are capable of targeting cccdy
Dear @chigoziekingsley5454 ,
Welcome to the forum and thanks for your great question. There are no current drugs that can directly target cccDNA, but this is an active area of research. Please see our research showcases to see what is currently going on in development:
Thomas
1 Like
The formation of cccdna, required a reaction to occur inside the cell genome, I guess there should be a way to block, or disrupt either by blocking the oxygen supply or the carbon
Dear @chigoziekingsley5454 ,
The trick here is to target the specific degradation of cccDNA without affecting the overall health of other liver cells (and ideally the health of the cells in question containing cccDNA). General approaches like the one you are describing would stop the metabolic activity of ALL cells in the liver (not a good idea!).
So for targeting cccDNA we need something like the following:
- Ideally targeted to the liver.
- A mechanism which will not affect the functioning of liver cells.
- Target the DNA of cccDNA without affecting DNA in chromosomes.
- Be able to target cccDNA with all sorts of mutations (there are populations of these in every person with chronic HBV infection).
- Be able to target cccDNA in its highly condensed latent form. Here cccDNA is immunologically silent.
As Thomas has mentioned, there is early work ongoing in this area. However, even with a highly active drug meeting all of the effects above, any residual cccDNA escaping such a drug would still be highly susceptible to reactivation in the presence of HBsAg. Currently, the most potent form of immune control with best overall clinical impact is functional cure (where HBsAg loss is critical). Here we know that cccDNA activity is perfectly controlled. The problem is that HBsAg is produced independently from cccDNA by another genetic form of the virus (integrated HBV DNA in host chromosomes). The challenges of targeting integrated HBV DNA are similar to those of cccDNA with the additional (and important) concern of exacerbating chromosomal structure / gene disruption already present with HBV DNA integration. These chromosomal changes are the primary cause for liver cancer developing in patients with chronic HBV infection.
It may be that such a cccDNA targeting drug could be part of a short term therapy and help improve functional cure rates, however, there is no such clinical data suggesting this yet and the animal models we have for human HBV infection are not so reliable in predicting clinical effects. I look forward to the entry of some of these early stage cccDNA targeting approaches into the clinic!
1 Like
Dear @availlant and @ThomasTu . I am new here. diagnosed a year ago with hep b. Thank you very much for your explanations and also for giving us hope that excellent work is underway. You are heroes, especially @ThomasTu because of your life story, because you had such high altruism with, at times, such low investments.
My question is looking for good news… when any of these studies demonstrate the capacity for functional cure, will there be as long an interval for the medicine to be distributed as it was with hep c? Or do today’s means allow for greater speed?
Thank you in advance
1 Like
Hi sir,
what can you say about bepirovirsen, an oral medication that will cure hepatitist b, that GSK and ionis pharmaceutical promised the world…?
Dear @La.sciamachie ,
Welcome to the forum.
This is actually a complicated question. The timing on the availability of any new HBV drug will depend on the following:
- When the drug is approved in individual countries.
- How much functional cure the drug can achieve or if it is restricted to certain niche patient populations.
- How much the drug will cost - this will influence if public / private healthcare will support paying for the drug.
With these intangables, even with today’s markets, it is not possible to predict how fast a new HBV drug will become available worldwide. In some countries the new HCV medications were available very quickly but were very expensive. On other countries it took a few years and significant price reductions before HCV medications became available.
1 Like
Dear @Suleiman,
Welcome to the forum.
Bepirovirsen is a medication which is administered in two phases. The first phase is a brief loading phase (typically given by IV infusion) followed by a longer phase where the medication is taken by a weekly subcutaneous injection. This drug cannot be taken orally.
Because of its action as an immunotherapy, this drug has achieved short term HBsAg loss during therapy with rapid rebound during early (6 months) follow-up in most patients. There are a small fraction of patients (~9%) who have maintained HBsAg loss at this time point but we have not seen the required longer followup (1 year) to see if these patients really have achieved functional cure. Unfortunately these effects were restricted to individuals with very low levels of HBsAg only present in 5-10% of patients. The current phase III study is only focusing on this niche patient population (so they are having a hard time finding patients to enroll).
Recently, GSK licensed the GalNAc-siRNA JNJ 3989 from J&J. Becuase of the failure of JNJ-3989 to achieve functional cure (even in combination therapy) and universal viral rebound in all patients, J&J closed down its HBV development program and has exited the viral hepatitis space. However, JNJ-3989 (again due its action as an immuotherapy) is able to achieve moderate HBsAg reduction in all patients (regardless of baseline HBsAg). JNJ-3989 must also be taken by SC injection once each month.
GSK likely hopes to develop a staged therapy where patients first take JNJ-3989, then bepirovirsen, then pegIFN.
This therapeutic approach will have to be tested for safety and efficacy in phase IIA studies not yet announced.
2 Likes