From scratch? Small molecule? Depends on which country you’re trying to sell it in and if the process is known.
If you knew the entire process, it would probably take a couple of months to source all of the materials and probably half a year to do the facility fit. Fortunately for drugs like this, you can use the preexisting equipment of your facility to do the manufacture.
One thing they don’t really tell you is that you need your facility to be approved to produce the drug substance. The plant will do a Process Validation (PV) using a Process Performance Qualification (PPQ) to produce initial commercial material which ultimately needs to be in a Long-Term Stability Study (LTSS). This takes would potentially take another year. While this is going on, the regulatory agencies will perform a Pre-Approval Inspection (PAI) to assess the plant’s ability to product quality and equivalent drug substance.
As the demonstration of the manufacturing process is going on, they can use the LTSS material to do the initial bioequilvalence clinical studies to demonstrate that the drug behaves in a similar way. If it’s a once daily small molecule pill, these studies can be fairly quick. Large molecules studies can take a year.
All of data goes into an Abbreviated New Drug Application (ANDA) to the FDA. This goes through three stages. A complete response (CR) where the FDA replies to the manufacturer. After that, a tentative approval (TA) is given followed by a full approval (AP). The FDA timelines for a CR, TA, and AP are 12 months, 24 months, 36 months respectively.
Overall, in the ideal case, you’re looking at 0.5-2 years for the facility fit, 1 year to do the PV, and 1-3 years for the ANDA to get reviewed and approved. This meets most of the typical timelines of 2-5 years that generic manufacturers typically work on.
If you don’t have a defined process that requires reverse engineering, process development and characterization, or you’re looking at a large molecule, those 2-5 years go up to 10.
Where things can get interesting is if the molecule is produced by multiple plants but only one is approved in a specific country. In that case, the PV and PPQ have already been done and all it takes is the PAI and ANDA approval.
Who ever said that there isn’t money to be made with off patent drugs?