With the anticipated launch of Lilly Korea's diabetes and obesity treatment Mounjaro (tirzepatide) in mid-August, its full-scale competition with Novo Nordisk's Wegovy (semaglutide) is expected to unfold.

Amid the imminent competition, the issue of whether to switch between the two drugs has emerged as a key point of contention in clinical settings.

#According to industry sources on the 11th, Lilly Korea plans to launch Mounjaro Pre-filled Pen (tirzepatide, hereinafter referred to as Mounjaro) 2.5 and 5 mg for patients with type 2 diabetes and obesity in Korea in mid-August.

Mounjaro is currently used in Korea as an adjunct to diet and exercise (as monotherapy or combination therapy) to improve blood glucose control in adult patients with type 2 diabetes, as well as in adult patients with obesity (initial BMI ≥ 30 kg/m2) or one weight-related comorbidity (hypertension, dyslipidemia, type 2 diabetes, obstructive sleep apnea, or cardiovascular disease) for chronic weight management as an adjunct to a low-calorie diet and exercise therapy.

For both indications, the recommended starting dose is 2.5 mg once weekly (for treatment initiation, not for blood glucose control or weight management), followed by 5 mg once weekly starting at week 4. If additional dose adjustment is required, increase by 2.5 mg after at least 4 weeks of treatment at the current dose, with a maximum dose of 15 mg once weekly.

The attention is now focused on the competition between Wegovy and Mounjaro in clinical practice.

A key point of interest in this process is whether patients previously treated with Wegovy will switch to Mounjaro.

Although there are no direct comparative studies, based solely on the results revealed during the development process, the weight loss effect of Mounjaro appears to be more pronounced. Considering this, some patients who were previously receiving Wegovy may express a willingness to switch to Mounjaro.

In response, Lilly Korea stated that the decision to change the type of medication or treatment method prescribed to patients should be made through discussion between healthcare professionals and patients.

A representative from Lilly Korea stated, “We have not conducted any studies on switching from GLP-1 RA to Mounjaro for chronic weight management on our own. However, we have a Phase IV clinical trial called SURPASS-SWITCH-2, which involved switching from GLP-1 RA (semaglutide, dulaglutide, or liraglutide) to Mounjaro in adult patients with type 2 diabetes for 12 weeks. The study was not designed to provide long-term results, efficacy comparisons, or optimal switching strategies, as these may vary depending on individual characteristics."

In clinical practice, not many patients are expected to switch from Wegovy to Mounjaro, considering how the initial dose of Mounjaro is 2.5 mg.

Chul-Jin Lee, President of The Korean Society For the Study of Obesity (Joeun Family Clinic), said, “explained, “Just because Mounjaro has been launched does not mean that patients who were previously receiving Wegovy will easily switch treatments in the short term. This is because patients who were receiving high doses of Wegovy may experience relatively lower efficacy when switching to 2.5 mg of Mounjaro.”

Lee said, “If Mounjaro is released, it should be offered first to new patients. The 2.5 mg dose has an advantage in terms of price for patients as it is not covered by insurance, but for the 5 mg dose and above, the volatility of the range of the non-reimbursed price must also be considered.”

Meanwhile, the supply price for Mounjaro has recently been finalized. The currently known domestic supply prices for Mounjaro are KRW 278,066 for 2.5mg, KRW 369,307 for 5mg, and KRW 521,377 for both 7.5mg and 10mg. The dosage forms to be launched in Korea this month are 2.5mg and 5mg.

For reference, when Novo Nordisk launched Wegovy in Korea last year, the supply price was set at KRW 372,025 per month regardless of dosage. Accordingly, patients who receive Wegovy as a non-reimbursable drug, mainly at outpatient clinics, must pay an average of KRW 500,000 to 600,000 per month.

Considering this, when the supply price is taken into account, the non-reimbursed price of 2.5 mg of Mounjaro is expected to be cheaper than Wegovy, but 5 mg is expected to be priced similar to the monthly cost of Wegovy.