Oral GLP-1s: the real battle isn’t at launch, it’s in persistence
The oral GLP-1 market has entered a new phase with the arrival of orforglipron (Foundayo, Eli Lilly), now competing directly with Wegovy (Novo Nordisk) in its oral form. At first glance, the narrative seems straightforward: a new entrant showing early traction versus a product that has already demonstrated scale. But, as is often the case with launches in this space, early data can be misleading.
The data for Wegovy oral (Novo Nordisk) helps frame the context. According to IQVIA figures cited by Reuters, its early trajectory was both rapid and consistent:
Week 0 (4 days): 3,071 TRx
Week 1: 18,410 TRx
Week 2: 26,109 TRx
Week 5: 38,220 TRx
Week 13: 105,366 TRx
Week 14: 113,354 TRx
The pattern is familiar: strong early growth followed by gradual deceleration as the product scales.
For Foundayo (Eli Lilly), the available data is far more limited:
Week 1 (partial, ~2 effective days): 1,390 TRx
On the surface, the gap looks significant. But that single data point isn’t directly comparable without adjusting for time on market.
Once adjusted, the picture changes.
Wegovy generated roughly ~768 TRx per day in its initial phase (3,071 over 4 days). Foundayo’s first read comes in at approximately ~695 TRx per day. In other words, Foundayo’s launch velocity is about 10%–15% below Wegovy’s on a like-for-like basis.
That’s not a dramatic gap—but it’s not neutral either. Wegovy started stronger.
What the clinical data says… and what real-world use might show:
Beyond initial velocity, attention quickly shifts to clinical profile. This is where the ORION-type indirect comparison becomes relevant, using data from separate trials (OASIS-4 for semaglutide and ATTAIN-1 for orforglipron).
The findings point to two consistent signals:
- An advantage for oral semaglutide in weight loss (~3 percentage points)
-Higher discontinuation rates with orforglipron, particularly due to gastrointestinal side effects
This is not a head-to-head study, and that limitation matters. But it does highlight a potential difference in the balance between efficacy and tolerability.
There is also a practical, real-world dimension. Foundayo follows a dose-escalation regimen, with monthly titration to higher levels. Regulatory data shows that gastrointestinal side effects increase with dose. The implication is fairly straightforward from a market perspective: early weeks reflect patient uptake, while later weeks reflect patient retention.
How to read TRx without overreacting:
It’s easy to overinterpret early prescription data. TRx (Total Prescriptions) combines both new prescriptions and refills, so it doesn’t cleanly separate growth from retention.
That’s why analysts also look at NRx (new prescriptions) and, more importantly, how week-over-week growth evolves.
For Wegovy (Novo Nordisk), the pattern is clear:
Week 1 → 2: growth above 40%
Following weeks: steady expansion to ~38k
Week 13 → 14: growth around 7%
This reflects a typical progression from hypergrowth to normalization.
For Foundayo (Eli Lilly), there simply isn’t enough data yet to draw the same conclusions. But that will be the key question over the next few weeks: whether growth holds as treatment advances and higher-dose dynamics begin to matter.
With the current information, a gradual divergence in the coming weeks looks like the most plausible outcome. Wegovy oral (Novo Nordisk) should continue growing from its current base of ~113,000 TRx, albeit at a slower pace, consolidating its patient base. Foundayo (Eli Lilly), meanwhile, is likely to grow rapidly from a low starting point. But the real question isn’t whether it will grow—it will—but how much of that growth is sustained once the therapy enters a more demanding phase.
Ultimately, the difference lies not in the launch, but in the shape of the curve. Wegovy has already shown it can scale beyond 100,000 weekly TRx. Foundayo still needs to demonstrate it can follow that path without losing momentum.