Pfizer announced today that it had chosen to terminate further development of danuglipron (also known as PF-06882961), which was a GLP-1 receptor agonist that was being developed for the treatment of patients with obesity. It is not because there was a lack of efficacy; on the contrary, it noted that it had seen a highly concentrated pharmacokinetic profile in the ongoing studies. Plus, a competitive efficacy similar to that of other GLP-1 receptor agonists on the market that have been approved by the FDA.
It was because of one patient who had drug-induced liver injury while taking danuglipron. The good thing here, though is that as soon as the patient stopped taking the drug, they had recovered without incident.
Things looked very good for this program, because the safety database it had amassed made it appear as though the drug was safe and tolerable to take. As a matter of fact, it was for the 1,400 patients who were given it. Despite liver enzyme elevations, which are typical for a drug of this class, the company could have competed well against the likes of Novo Nordisk with its drug OZEMPIC and Eli Lilly with its drug ZEPBOUND (tirzepatide).
This wouldn’t have been so bad if the discontinuation of this molecule was the only setback that Pfizer had suffered with respect to advancing it to treat patients with obesity. For starters, it began its development of danuglipron as a twice-daily formulation. However, it couldn’t move the development of this drug forward in this treatment dosing regimen because patients in a mid-stage study couldn’t tolerate it. Thus, it had to move to a once-daily formulation in hopes of establishing an efficacy profile similar to that of other GLP-1 agonists, but one that would be more tolerable to take on a daily basis.
Far before the need to switch from twice-daily danuglipron to once-daily formulation, it had another obesity drug it was developing. This was a drug known as lotigriplon and was being advanced as a weight-loss drug as well. However, with elevated liver enzymes in play after only being developed as a once-daily option for these patients made big pharma scrap it. It was believed then that danuglipron was the better option to move forward with at that time in 2023. It appears as though while such a decision was warranted at that time, it didn’t work out well.
Having said all of this, shares of Viking Therapeutics and Structure Therapeutics traded much higher on the back of this news. The reason why is because, quite simply, Pfizer hasn’t had any luck when it has come to developing a weight-loss drug that is not only efficacious but also safe/tolerable for obesity patients to take.
Viking Therapeutics is ideal because it has a subcutaneous version of its GLP-1/GIP drug VK2735 for the treatment of patients that it is expecting to start a phase 3 study with in Q2 of 2025. Plus, the oral version of this very same drug is in phase 2 clinical testing. Even better, the company expects to release data for the oral version of VK2735 in the 2nd half of 2025. The mechanism of action for this drug is the same as that of Eli Lilly’s blockbuster ZEPBOUND. Thus, it is my belief that Pfizer could decide to acquire Viking Therapeutics, because after so many setbacks it might be the best course of action.
In terms of Structure Therapeutics, it is developing a drug known as Aleniglipron (GSBR-1290), which is an oral GLP-1 receptor agonist for the treatment of patients with obesity. What makes this unique is that it could be a best-in-class drug of its kind because of the selectifive nature of its mechanism of action. It avoids β-arrestin signaling, and this is thanks to the selective nature of targeting only G-coupled protein receptors. This is another company to watch in the short-term because it is also expected to have data releases. It expects that it will release data from its phase 2b ACCESS and Phase 2 ACCESS II studies evaluating the use of aleniglipron for the treatment of patients who are obese or overweight. Such data is expected in Q4 of 2025.
Even though Pfizer has seen setbacks in the obesity space, at least it has a few options to recover from. In essence, it would be ideal for it to take its pick of either one of these two biotechs to acquire. It has plenty of cash, and it makes sense after so many trial setbacks in getting a weight-loss drug to market. With a successful acquisition, it would make back its money anyways. The reason why is because the global anti-obesity drugs market is expected to grow to $104.9 billion by 2035. The opportunity exists for Pifzer; it just has to take the leap of faith to make a bold move acquire something and get its growth back on track.
