Since you can’t eat a protein drug as it will be broken down and not absorbed, what alternative routes are there?
Injection seems to be the main one. Are there more convenient ones?
What about something like an IUD, some kind of implant that releases small amounts of the protein in question over time. Would that work, or would the proteins degrade?
Even if it was a problem, couldn’t you create some kind of subcutaneous patch then inject new proteins in on a monthly basis or so? That would be more convenient than daily injections. Once a month inject some new proteins into your implanted patch, then they get released over the course of the month.
What about nasal administration? What about microneedle patches? Are those realistic anytime soon?
There’s been various attempts at inhalable insulin, so that’s one option.
One of the issues you’d have with the various options you list (implants, etc) is dosage. If the dosage isn’t evenly-spaced throughout the day, how would you control it?
The other question is “what happens if you need to stop it?”, ie, you have an allergic reaction, or the stuff isn’t working, or whatever. Any drug delivery system would need to have a way to stop it, and “surgery” isn’t going to be a good answer for most people.
Here is an article about research into preparing protein drugs as “nanoclusters” in solution, in hopes of avoiding larger clumping. The goal is to package more protein drugs in an easily self-injectable form, like insulin, so as not to have to resort to expensive, time-consuming IV drips.
Injection is often the preferred delivery method in oncology - an area where biologicals are probably most represented and continue to grow. For something life-threatening like cancer, a clinician needs total compliance with the medication, and the patient will be visiting hospital in any case.
For non life-threatening conditions, arthritis say, then regular injections are problematic for reasons already stated.
Thinking up new drug delivery systems is an eternally popular research area - it lends itself to very creative and imaginative science, with a breakthrough having the possibility of massive translational importance. I’m not aware of anything really novel coalescing out of that field as far as trad small molecule drugs go, but ISTM that biologicals such as proteins or nucleotides will drive discovery there at a much faster rate.
I think you are probably thinking of peptides rather than proteins. Most actual proteins are likely to cause an immune response if injected (or, indeed, if they get into the bloodstream in some other way), up and including causing death by anaphylactic shock. Insulin is a peptide rather than a protein.
He prob is thinking of proteins - most of the blockbuster biological drugs atm are monoclonal antibodies which are protein structures - often quite sizable ones.