4 ms·

Is "highly pure" really pure enough for the FDA? I knew a guy who worked on phages. The problem they ran into is when they submitted their virus to the FDA th

by tsotha 13y ago

Is "highly pure" really pure enough for the FDA? I knew a guy who worked on phages. The problem they ran into is when they submitted their virus to the FDA there was no way they could guarantee the absence of dangerous mutations in a given batch. EDIT: I should say I didn't follow his work that closely, so it's possible there were efficacy problems as well.

bhickey 13y ago
The bar has certainly been met with regards to phage as a food additive: http://www.fda.gov/OHRMS/DOCKETS/98fr/cf0559.pdf http://www.fda.gov/OHRMS/DOCKETS/98fr/cf0559.pdf The error rate of an E.coli DNA polymerase in vitro in <9x10^-6. Lambda phage, for example, has a genome that's about 48 kilobases in length. Which gives a mean error rate of 0.432 bases / replication. Ballpark estimate that the phage goes through 30 replications to produce a plaque, so we're talking ~13 mutations (it's a little different than that due to the founder effect, etc). It isn't like a phage is going to jump Kingdoms and start predating you instead of the preferred host. This simply isn't a realistic risk, while the immunogenicity issues could be. In terms of my own risk tolerance, I would have been comfortable drinking any of my own samples.
- tsotha 13y ago
  >In terms of my own risk tolerance, I would have been comfortable drinking any of my own samples. Hmmmm. Maybe so, but would you inject them?
  - bhickey 13y ago
    If there was a medical need and they were shown to be efficacious, sure. I'm currently receiving allergy shots which involves frequent injections of dust mites. Injections are followed by a 30 minute observation period as a caution against anaphylaxis. Staff are on hand to intubate. The frequency of life threatening reactions is around 1 in 10^6. If phage were ever used clinically, I suspect the protocol would be similar. I mean, heck, some people have life threatening reactions to common antibiotics (I believe sulfa allergies are particularly common), but that doesn't keep them out of use.

by tsotha 13y ago

bhickey 13y ago

The bar has certainly been met with regards to phage as a food additive: http://www.fda.gov/OHRMS/DOCKETS/98fr/cf0559.pdf http://www.fda.gov/OHRMS/DOCKETS/98fr/cf0559.pdf The error rate of an E.coli DNA polymerase in vitro in <9x10^-6. Lambda phage, for example, has a genome that's about 48 kilobases in length. Which gives a mean error rate of 0.432 bases / replication. Ballpark estimate that the phage goes through 30 replications to produce a plaque, so we're talking ~13 mutations (it's a little different than that due to the founder effect, etc). It isn't like a phage is going to jump Kingdoms and start predating you instead of the preferred host. This simply isn't a realistic risk, while the immunogenicity issues could be. In terms of my own risk tolerance, I would have been comfortable drinking any of my own samples.

tsotha 13y ago
>In terms of my own risk tolerance, I would have been comfortable drinking any of my own samples. Hmmmm. Maybe so, but would you inject them?
- bhickey 13y ago
  If there was a medical need and they were shown to be efficacious, sure. I'm currently receiving allergy shots which involves frequent injections of dust mites. Injections are followed by a 30 minute observation period as a caution against anaphylaxis. Staff are on hand to intubate. The frequency of life threatening reactions is around 1 in 10^6. If phage were ever used clinically, I suspect the protocol would be similar. I mean, heck, some people have life threatening reactions to common antibiotics (I believe sulfa allergies are particularly common), but that doesn't keep them out of use.