Ozempic or Mounjaro: is switching really worthwhile?

The results attracted attention and contradiction. Lilly Germany emphasises that no generally valid therapy recommendations can be derived from the analysis and points to the existing evidence from randomised clinical trials, which shows tirzepatide to be superior to semaglutide on several endpoints.²

So what does this mean in practice? Should patients switch from Ozempic to Mounjaro, or better not?

Two studies — two statements

At first glance the results appear to contradict one another. In fact, however, the questions they ask differ fundamentally.

The analysis presented by Novo Nordisk examined people with type 2 diabetes who were already being treated with semaglutide 1 mg. It compared titrating up to 2 mg with switching to tirzepatide. The evaluation showed that both strategies were similarly successful when it came to reaching an HbA1c below 7 %. In achieving weight loss of at least five per cent, titrating up the semaglutide even performed somewhat better in this analysis.¹

Eli Lilly, by contrast, points to the large randomised SURPASS-2 trial. There tirzepatide was compared directly with semaglutide 1 mg — but in patients newly enrolled in the respective therapy. In that trial tirzepatide led both to a stronger reduction in HbA1c and to greater weight loss.²

The apparently contradictory results are therefore explained above all by different study designs and different questions.

Real-world data are important, but no substitute for clinical trials

The investigation presented by Novo Nordisk is based on so-called real-world data. Such analyses reflect everyday care and deliver valuable insights into how medicines are used outside strictly controlled trials.

However, real-world analyses can never entirely exclude statistical differences between patient groups. Factors such as age, comorbidities, adherence or the reasons for a change of medication can only be taken into account to a limited extent. Randomised controlled trials therefore remain the gold standard for directly comparing the efficacy of different medicines.

The new data thus provide interesting indications, but do not conclusively answer the question of the optimal therapy switch.¹

When can a switch make sense?

A blanket switch from Ozempic to Mounjaro cannot be recommended on the basis of the currently available evidence.

Whether a switch makes sense depends far more on the individual therapy goals. If good blood glucose control is achieved on semaglutide and the patient tolerates the therapy well, there is frequently little to be said for a routine switch. If glycaemic control is inadequate, however, or if greater weight loss is sought, tirzepatide may be a sensible option because of its dual action on GLP-1 and GIP receptors — provided the individual circumstances and the applicable authorisations are taken into account.³

Tolerability, comorbidities, cost, availability and patient preference likewise play an important role.

What does this mean for pharmacies?

For community pharmacies the debate shows one thing above all: the choice of a GLP-1-based medicine cannot be reduced to simple comparisons.

Patients pursue different goals. While for some the reduction of HbA1c is paramount, others want above all weight loss or the best possible tolerability. Counselling must be correspondingly individual.

Pharmacists can help to avoid unrealistic expectations. Not every new study automatically means that existing therapies should be changed. Nor is every newer medicine fundamentally the better choice.

In a market increasingly shaped by intensive marketing activity and competing study data, evidence-based interpretation is gaining importance.