Rebuttal to OpenPhilanthropy.org's list of objections against DRACO

[rick]

Some time ago, the folks at openphilanthropy.org posted a long article with their objections against DRACO: https://www.openphilanthropy.org/informal-writeup-dracos-potential-antiviral-treatment

No one has yet undertaken a rebuttal, so I thought the time is right. I can't say I'm thrilled about the idea of posting and discussing a link with so much misinformation in it, but given the likelihood of it coming up in any serious Google search or due diligence investigation, it's better to just address it head-on. I'd like to discuss each objection in a detail when I can, so this will be a thread, not just one giant post.

Chris Somerville spent 2 hours reading about DRACOs and then discussed for about an hour with Holden.

Chris, who is not a virologist, emailed a friend with knowledge of virology about DRACOs for a quick opinion.

In other words, the authors aren't experts, and only spent a few hours thinking about things. This gets more obvious as time goes on.

Complicated delivery: For DRACOs to work as a therapy, there needs to be an efficient method for therapeutically delivering proteins inside of cells in intact animals. Protein motifs (PTDs) that can induce uptake by cultured cells were used in the Rider paper and have been widely used experimentally. By contrast, delivery of therapeutic proteins into cells in live animals is relatively poorly described in the literature.

Protein transduction tags (PTDs) were demonstrated in Rider's paper as working effectively in live mice. The paper describes successful and safe treatment of mice against Influenza H1N1 using DRACO, including tags to deliver the protein into cells.

In addition, earlier research showed the effectiveness of transduction tags in live mice. For example:

The graphic above shows how a transduction tag delivered a protein into a wide range of tissue types in mice, including the brain (so it passes the blood-brain barrier), and that there were no side effects in these mice after 2 weeks of use.

On the left in the graphic above, a fluorescence study visually shows the effectiveness of transduction tags at carrying DRACO into human lung fibroblast cells. With the TAT tag, as above, the concentration of the protein in the nucleus appears higher than the cytoplasm, although there is still a significant amount in the cytoplasm.

The diagram also shows how the concentration of DRACO in cells increases over time, first appearing at about the 10 minute mark, reaching a maximum after about 1.5 hours, and lasting for at least 11 days.

The ultimate test of the effectiveness of transduction tags was the fact that DRACO performed as expected against 15 different types of viruses in 11 different tissue types, and against 3 different viruses in mice (only Influenza was mentioned in the paper; the other two came later). As in the prior studies, the DRACO-treated mice were happy and healthy:

Is it possible that there are some cells or tissues which transduction tags won't reach in adequate quantities when our compound is injected, ingested or inhaled? Sure, it's possible, although you could say the same thing about any drug and administration method. But to say the mechanism is "complex" and "poorly described" in animals is disingenuous at best. It's actually a simple, safe and extremely elegant cellular delivery mechanism.

[rick]

Whatever delivery method there is would likely have to be more complicated than a pill and might require skilled administration, limiting potential for widespread or quick use.

Rider's paper used two methods of administration: intraperitoneal injection (i.p.) and intranasal (i.n.). I.p. injection in mice is often used simply because it's easier than other forms of parenteral administration. I.n. basically consists of letting the mouse inhale the substance through its nose (see the short video below). Neither of these are complex in mice.

Intranasal immunization of mice

In humans, we don't know the best method of administration yet, and in fact it might vary from one virus to another. The equivalent of i.n. in people would just be a nose spray; i.p. would be an intravenous injection or IV drip. In mice, i.n. was effective in treating Influenza, partly because the lungs and airways are the tissues most affected by the virus. The same may be true in humans.

It's possible that oral administration will be possible in humans, particularly for viruses that affect the gut, but also systemic. Although DRACO is a protein, there are many well-established ways to effectively protect proteins from enzymes and early digestion (enteric coatings, for example).

Even though the most effective method of administration is something we intend to investigate, there's nothing here that limits the potential for widespread or quick use.

Dangerous: For DRACOs to work, it would be necessary to deliver a lot of protein to cells (because DRACOs have to get into all cells that might be infected). Based on the mouse studies reported by Dr. Rider, it seems possible that a gram or more of DRACO would need to be administered to humans

The doses used in the paper for i.p. were 0.8 to 2.5 mg in 200 ul (4 to 12.5 g/L concentration), or for i.n. 0.5 mg in 50 ul (10 g/L). The conventional rule-of-thumb scaling factor between mouse and human dosing is based on skin surface area. On a mg/kg basis, that works out to dividing by a factor of 12.3. So, a little math: 2.5 mg absolute / 50 g typical mouse = 50 mg/kg. Scaling to humans: 50 / 12.3 = 4.1 mg/kg. Scaling to a 70 kg human: 4.1 * 70 = 287 mg. If it ends up being possible to take it orally and in powder (perhaps lyophilized / freeze-dried) form, that's about the same as a medium-sized vitamin pill.

In terms of injection amount, assuming the i.p. concentration of 12.5 g/L, a 287 mg dose would be about 23 cc. Although that's too much fluid for I.M. or simple by-hand venous injection, it's easily done with an I.V. drip. Note that Rider doesn't say what the concentration of a saturated solution is; it's possible that we will be able to make it much more concentrated than he did.

However, there's an important caveat about the above numbers. Rider also measured the minimum dose at which DRACO was fully effective, and found it to be only 10 nM/L, which is unusually low as conventional drugs go; it's roughly the same order as human hormones. For example, the concentration of typical human thyroid hormone (T4) is about 100 nM/L. The oral dose of T4 required to maintain homeostasis is on the order of 100 mcg/day. If we crudely apply the same scaling to DRACO, it suggests a dose of only 10 mcg might be enough to achieve the effective in-cell level of 10 nM/L. That's a factor of some 28 million less than the dose used in the original study.

Dr Rider clearly didn't (and couldn't) know what the required dose would have to be before he started his study. My take on his work is that he gave the mice the highest dose he could that he thought wouldn't be toxic. Importantly, even at the high mg/kg doses he administered to mice, the mice still didn't show any toxic effects. One of things we plan to test for is exactly what the dose really needs to be in people, but as I've explained above, we have good reason to be hopeful that it can be quite low.

[rick]

Because DRACOs contain a non-human component, it is very likely that they will induce a strong immune response.

On the theory side, DRACOs are mostly made from parts of two existing human proteins. The only non-human component is a very short peptide (roughly 9 to 11 amino acids), which is a transduction tag. Based on this, while some immunogenic response is possible, as with all drugs, the odds of it being significant are small. It's certainly much safer and less immunogenic than current approaches that use entire active viruses to deliver payloads inside cells.

On the practical side, the mice that were treated with DRACO in the 2011 study showed no signs of either toxicity or immunogenecity, in spite of the relatively high doses they received.

Viruses sometimes infect large numbers of cells. If DRACOs succeeded in killing all human cells with viruses in them, that could mean killing very large numbers of human cells, potentially posing substantial health risks.

This is a valid concern. One of the ways that VTose is different from DRACO is that we have several potential solutions. I can't say too much more at the moment, though, other that this is something we've given considerable thought and attention to.

Nature could have evolved a mechanism for triggering apoptosis in cells with dsRNA, but appears not do it naturally.

Yes, nature could have done that -- and it did:

You can see PKR in the middle of the diagram, attached to dsRNA, which triggers FADD, then Caspase 8, which causes apoptosis.

The problem with this pathway is that viruses like to interfere with it. For example, Caspase 8 is a common target:

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4515451/

There is a risk that some cells may naturally have enough dsRNA that they could potentially be attacked by DRACO despite being healthy. The proteins used in the DRACO system are most strongly activated by long dsRNA which is intended to make the mechanism specific for viruses. However, short dsRNA of 11-16 nucleotides can bind to the dsRNA binding sites and activate the proteins under some conditions.

Activation of the apoptosis requires binding of two molecules of DRACO to dsRNA, as shown in the above diagram for "regular" PKR. This requires at least 30 to 50 base pairs of dsRNA. Short segments don't and can't bind. If they did, they would activate PKR in healthy cells, along with all of its downstream effects. Uninfected mammalian cells generally do not produce dsRNA longer than 21 to 23 base pairs.

Harmless viruses in cells could be targeted by DRACOs as well, posing additional risk (i.e., widespread cell death).

I would like to know which viruses the author considers harmless. There are viruses like CMV and EBV that often produce subclinical symptoms, but there's also clear evidence that they're harmful. The widespread cell death issue was addressed earlier.

Bacteriophages are viruses that attack bacteria, and may be helpful as a result. DRACO doesn't affect bacteriophages.

[rick]

In light of the safety concerns above, it may not make sense to use DRACOs to treat low-stakes conditions like rhinovirus (the common cold).

The safety concerns were debunked above. It's possible that a low-dose DRACO administered by nose spray may end up being an inexpensive and effective treatment for the common cold. We already know DRACO is effective against Rhinovirus, so that's an important first step. As with any new drug development, there are, of course, questions to be answered and investigations to be done. However, based on what we know today, we don't see any show stoppers.

While it might make sense to use a risky treatment against a very deadly virus, DRACOs would not work against HIV because this virus does not rely on dsRNA.

HIV is a Lentivirus, which is a positive-sense single-stranded RNA enveloped retrovirus:

These viruses are similar to Dengue virus, which DRACO was found effective against in Rider's paper:

SARS-CoV-2 is also a (+)ssRNA enveloped virus.

Although HIV's viral genome uses ssRNA, the viral replication process still uses dsRNA -- as do all viruses.

One difference is that Dengue is not a retrovirus like HIV, nor were any of the tested viruses, and retroviruses do behave a bit differently in some ways than other viruses. However, since dsRNA is still present while a retrovirus virus is replicating, there's good reason to believe DRACO will be effective. We do, of course, need to test to be sure.

The Rider paper presented some preliminary mouse trials which indicated significant protection against life-threatening viral infections. However, the trials were quite short and there was no detailed analysis published of effects on the overall health or longevity of the mice. If further experiments were done, the emphasis should probably be on long-term health effects on a variety of animals with and without viral infections

I agree with this point. Rider described his trials with mice as a "proof of concept." We learned many interesting and useful things as a result, but more work remains, including longer-term studies.

Crowdfunding page cites the “valley of death” as an explanation for why the NIH is not funding work on DRACOs. Chris is skeptical of this explanation. He thinks that antivirals are a very hot area, and that it’s generally easy to get funding and interest around in vitro/cheap-animal trials of things that have worked before. Given above point, Chris thinks it’s a bad sign that there has been so little follow-up research since the Rider paper.

What I've heard is that it's generally easy to get NIH funding for basic research, and for the final take-it-to-market step, but not for the in-between phase that involves clinical trials and the like. But I wasn't there, so I can't say for sure what happened. I have done my fair share of US Gov-funded research though, and can say with some authority that they are a fickle beast, and that politics and hidden third parties are often involved. From where I'm sitting the lack of NIH funding simply means someone at NIH decided there was some reason not to fund it. It tells me exactly nothing about what that reason was. What the rest of us should be doing is looking critically at the science in the paper. Surprisingly, the critique on which this thread is based seems to have completely avoided that approach.

Given the points above, Chris’s guess is that there are further reasons and possibly further evidence for the unpromising-ness of DRACOs that we aren’t seeing.

Guesses and possibilities about things imagined aren't helpful. At this stage of the paper, and as I hope you can see from my rebuttal above, it sure looks to me more like a hit piece, and less like honest journalism.

END

[carrieb]

Regarding the article's claim that "If DRACOs succeeded in killing all human cells with viruses in them, that could mean killing very large numbers of human cells, potentially posing substantial health risks"--

My understanding is that VTose would only be able to target cells containing active viruses that are producing dsRNA. If a virus such as varicella is in the latent phase, it would not be producing dsRNA (based on my understanding of viruses, at least). Hopefully there will be a way to grow cells with latent viruses and investigate the likelihood of VTose affecting such cells.

[rick]

@carrieb

Regarding the article’s claim that “If DRACOs succeeded in killing all human cells with viruses in them, that could mean killing very large numbers of human cells, potentially posing substantial health risks”–

My understanding is that VTose would only be able to target cells containing active viruses that are producing dsRNA. If a virus such as varicella is in the latent phase, it would not be producing dsRNA (based on my understanding of viruses, at least). Hopefully there will be a way to grow cells with latent viruses and investigate the likelihood of VTose affecting such cells.

Yes, that's definitely an area we want to explore.

Retroviruses as well as Herpesviruses like Varicella have a latent phase. The good news is that as long as a virus remains latent, it also isn't damaging the cell or interfering with its function. It's only when the virus starts to replicate inside the cell (Lytic replication) that it causes cell damage or cell lysis or immune system activation -- and when Lytic replication begins, dsRNA appears. It may be that the change from Latent Replication to Lytic Replication actually works in our favor when infections are widespread, allowing infected cells to be pushed into apoptosis more incrementally. However, it's an area we need to study to be sure.

[steve]

What I find deeply astonishing and a bit disturbing about DRACO is the fact that although it seems to be a solution for a broad class of virus related diseases that could help every single person on earth, no one looking at it has regarded it worthy of any kind of investment. Have other professionals in the field seen something that you don't yet see?

In this context it is also a bit startling that Mr. Rider promotes himself as an universal genius who solves everything from virus technology to antimatter rocket propulsion. But he does not seem to have any kind of commercial success with all that. My experience tells me that people like Mr. Rider usually tend to make up a lot of their "inventions" and shouldn't be taken to seriously. Has some else ever replicated his DRACO work? What if you find that most of what he had written is falsified?

[rick]

@steve

What I find deeply astonishing and a bit disturbing about DRACO is the fact that although it seems to be a solution for a broad class of virus related diseases that could help every single person on earth, no one looking at it has regarded it worthy of any kind of investment. Have other professionals in the field seen something that you don’t yet see?

It's disturbing to me, too. In fact, so much so that I co-founded a company to carry the work forward.

The professionals I've discussed Rider's work with so far have had a couple of minor technical criticisms of his paper, but nothing that would invalidate his results.

Keep in mind that the PLoS ONE journal, where the original paper was published, is peer-reviewed--which means the reviewer professionals also didn't see anything significantly wrong.

If you carefully read the paper, it's actually a tour de force. Rider did much more work than he had to for a basic paper. My guess is that he may have suspected he wouldn't be believed, so instead of reporting results on one virus, he tested 15. Not one virus family, but seven. Not just one genome type, but four. Not just one tissue type, but 11. Not just in vitro, but also in vivo in mice. He even verified mechanism of action and ruled-out effects by secondary compounds.

The odd thing is that nearly all would-be investors ask the same question: "If it's so great, why didn't it get funding before?" Well, guess what? If everyone thinks the same thing, then funding never happens. Someone needs to be first, to make the leap. In my experience, investors as a group hate being first; they much prefer to follow than to lead.

@steve

In this context it is also a bit startling that Mr. Rider promotes himself as an universal genius who solves everything from virus technology to antimatter rocket propulsion. But he does not seem to have any kind of commercial success with all that. My experience tells me that people like Mr. Rider usually tend to make up a lot of their “inventions” and shouldn’t be taken to seriously. Has some else ever replicated his DRACO work? What if you find that most of what he had written is falsified?

My view is that Rider is a gifted scientist and researcher. However, it takes an entirely different set of skills to raise money and run a business.

Reporting false results would have required cooperation from his team at MIT Lincoln Lab. I've corresponded with two people there who worked with him, and neither one gave any indication in that direction. MIT/LL is a reputable research lab that would certainly not allow that kind of thing.

In addition, yes, work on DRACO has been replicated and published. First, in 2015 at a lab in China, where they tested against Porcine Reproductive and Respiratory Syndrome Virus (PRRSV), using a monkey cell line:

https://pubmed.ncbi.nlm.nih.gov/25772577/

Then again more recently, just this year, in a lab in Iran, where they found effectiveness against Influenza:

http://www.biotechrep.ir/article_111083.html

As an aside, note that the above two papers are much more "conventional" than Rider's. One virus, one cell line--and yet still interesting enough to warrant publication.

One of the first things we plan to do as a company is to replicate the work ourselves, too. It's not that we don't believe in or trust the prior results. Rather, the technology in this area has evolved considerably since 2011. We want to make sure we've correctly carried the original work forward to the latest fabrication methods.

[steve]

Thank you for the reply! Your arguments make sense. And the two additional papers give indeed some more legitimacy to Rider's work.

[abotnick]

What kind of VTose dosing duration and schedule are we looking at for injections? My concern is that apoptosis is very intense.  I have a treatment worked out, Craysing, that appears effective for combined HHV6 and EBV infection which is administered by mouth and that one appears to be taking 9 months.  I think the limiting factor is that it relies on antibodies and can only cover so many cells per day so you get a layer by layer removal of infected tissue.  However, if we induce the same amount of total apoptosis within an accelerated time frame, say 3 months, then we have do deal with a much bigger cytokine load which could harm the patient.

One problem I see with the previous patent is that it was very broad, allowing for multiple capsases attached to the transduction tag. FDA drug approval takes a long time (though you might be able to get emergency use authorization to speed it up) and is very costly so without the ability to patent I don't think you would be able to raise enough money through venture capitalists to complete the funding.  I hope you are able to secure a patent.  

[rick]

@abotnick

What kind of VTose dosing duration and schedule are we looking at for injections?

For Rider's study with mice to treat Influenza, he only treated them for a few days.

Dosing in humans will depend on a number of factors, such as the type of virus being treated, the severity of the infection, whether there are other viral co-infections, and so on. We are also looking at formulation changes that are intended to influence the required dose. The specifics in this area are one of the many things that we plan to determine during clinical trials.

[abotnick]

Ok, for a 10 year myalgic encephalomyelitis patient who has to clear years of infected cells what are we looking it?  # of injections over what time interval?  Can an oral form be developed?

[rick]

@abotnick

Ok, for a 10 year myalgic encephalomyelitis patient who has to clear years of infected cells what are we looking it? # of injections over what time interval? Can an oral form be developed?

Specific treatment protocols is one of the things we will be researching.

We certainly will also be putting some effort into trying to develop an oral form. However, proteins are very susceptible to damage and degradation by the digestive system, so it's a challenge. Insulin, for example, which is a relatively small peptide (a short protein), still doesn't have an oral form.

[abotnick]

@rick

Specific treatment protocols is one of the things we will be researching.

We certainly will also be putting some effort into trying to develop an oral form. However, proteins are very susceptible to damage and degradation by the digestive system, so it’s a challenge. Insulin, for example, which is a relatively small peptide (a short protein), still doesn’t have an oral form.

I see the problem. Maybe a port can be put in temporarily for self injection for a year or so and checked monthly by the patient's primary care practitioner. This is a big hurdle. How often does it need to be injected? Your immediate concerns should be reformulating it for caspase 7 and securing a provisional patent.

[abotnick]

If you can't get that patent there is no way to raise the money to afford to complete the drug approval process.

 

[abotnick]

@rick

there’s nothing here that limits the potential for widespread or quick use.

My biggest concern is the chance that immune response that could give a serious anaphylaxis reaction in up to 30% of patients. Granted, it may not occur with VTose but that's a high number.

https://www.cell.com/molecular-therapy-family/molecular-therapy/fulltext/S1525-0016(16)33585-7