Like a "dangerous to use after 01/01/2019" label on things that actually are dangerous.
Other items could have labels like, "Safe for use until 01/01/2025 - Effectiveness may be degraded after 09/05/2019"
But nobody wants to run long stability studies, because that costs a lot of money (i.e. several batches that have to be analyzed in regular basis, documented, reported, QA'ed, inspected, etc... - and you need to place them in numerous conditions, too, ambient temperature as well as stressed conditions depending on where you intend to market the drug), and bring very little returns at the end of the day. You'd rather want your engineers to work on developing new formulations and regulatory teams to spend time on the application of new drugs rather than adding one or two years of shelf life to an existing drug on the market.
Also know that you can't "extrapolate" and need actual data based on regulations of the big 3 geographies (US, Europe, Japan). So "models" are not accepted. Also, these agencies are extremely conservative when it comes to what impurities should be considered acceptable and at what levels they should be. Not saying they are necessarily wrong, but this is another constraints. I have seen cases where it was difficult to extend one drug's shelf life because of a single impurity being a little over the tolerated limit.
Some medication that expires quickly can be extended simply by refrigerating it. I wonder what other environmental controls could extend the shelf life of common, expensive medication?
By storing it for 2 years and testing it after.
> I wonder what other environmental controls could extend the shelf life of common, expensive medication?
Common, expensive is an oxymoron. The vast majority of all medication in use is practically free to produce. The packaging of drugs typically costs more than the drugs themselves. Drug discovery has long concentrated on small-molecular-weight drugs that can be mass-produced for a pittance. The reason drugs cost so much is that proving that they are safe and that they work costs so much. Because of this, there is little economic sense in trying to preserve drugs for longer (which would require more extremely expensive trials), when you can just trash the drugs and order up a new batch that has a combined msrp of $100M for $5k.
In their economics, small molecular weight drugs share more with software than with, say, bread. That is, practically all of the economic cost is upfront investment and the replication cost is non-existent.
Apart from biologic drugs, most small molecule compounds are dirt cheap to produce. So cheap that nobody is even striving to produce them in a cheaper, more efficient way. If you compare this kind of industry with chemical specialty industries, where the mindset is to increase yield as much as possible, in pharma the production cost is not much of a consideration. So, what you pay for your drugs has almost no relationship to how much it costs to produce. You are paying for patents, market exclusivity and the whole system that goes with it (the pharma companies are not the only ones benefiting from it).
> How did they come to an expected shelf-life of 2 years in the first place?
Stability studies supporting 2 years data (submission to approval takes one year, and compiling all data before submission for filing is a 6 months process, so you can start submission with 1 year stability data in your hands, and tell the regulatory agencies you will provide the 2 years data during the second half of the regulatory review to get 2 years).
Because that's good enough for most drugs. 3 years is usually ideal, but not always necessary. If your drug is used in high volume most patients won't get batches that are produced long ago anyway.
Any drug submission that supports shelf life via ALT data will be expected to also say "and we're doing real time testing to support this", and FDA will expect the follow up real-time data.
But if, in reality, that drug only lasts for a strong 5 years, after which time it loses effectiveness, especially in high humidity or with high UV exposure. We could catch this with real-time tests and adjust accordingly - before it actually affects the general public's health.
For the vast majority of manufactured products, HALT makes sense because any uncertainty that remains after testing is not likely to harm users. But with some of these drugs, any uncertainty, even after HALT, could cause major problems for users. And it seems that the FDA is unwilling to accept that risk. But as far as I know, the FDA is actively seeking methods for performing HALT that produce accurate and repeatable results.
Given the amount of money spent on medicines, I really think there is a good moral business case to identify the correct expiration dates and save money for people.
We just went through the Health care ordeal. Money saved anywhere is money saved for people who desperately need healthcare to work for them.
Given that it's the very same party that would be doing the testing for expiration dates, I kind of doubt they would research this out of the goodness of their corporate hearts. Effectively the same outcome could be realised without the effort of extra testing anything: by just lowering the price of medicine a bit; big pharma would make less money, the public would have more medicine for cheaper.
A case could be made for legislation that obliges free replacement of out of date medication for the original purchaser, perhaps with a small surcharge.
The issue here though is that it's not in the drug manufacturers interest to have super long dates. Putting labels that expire sooner means they can push higher volume.
I assume that would be done after bringing a drug to market, otherwise drugs could easily be delayed 10+ years if they're shelf-stable.
If it's a new drug and they can only say for sure that it lasts 6 months then put that on the label and ship it out. But assuming the drug will be out for 10+ years they should be continually testing the expiration date and updating as they've had more time to make that determination.
But like I said initially (and as you nicely pointed out) that costs money so why bother?
This needs regulatory work. And this bring very little returns, so your regulatory resources are better spent somewhere else. There are other incentives in place.
It's very likely it is not favorable to companies to look into this, just as it was revealed that the EpiPen expiration date was not really true.
What kind of error rate are you willing to accept in models of pharmaceutical shelf stability? Bearing in mind that errors potentially translate into deaths, probably disproportionately of the less privileged among us?
"able to calculate the longevity of chemicals, food, and other products without having to wait the actual time period"
I'm not anywhere near knowledgeable on pharma, but I worked on an FDA regulated medical device. If we made a claim, we had to test it. Knowing that e.g. every component in the machine was rated safe between temperatures X and Y did not mean that we didn't have to perform real environmental testing.
There is a great comment farther down about how complex label changes can be. Getting a revised label, or packaging through FDA is an enormous undertaking. This why sometimes dosing seems very weird. If research says we need a 2mg and a 4mg but later in the process patients need a .5mg it's a big mess.
Suffice to say it's a deep rabbit hole.