Semaglutide Treatment: What a Course of Therapy Looks Like

Which semaglutide the course refers to

Semaglutide is a GLP-1 receptor agonist that activates receptors in brain areas that regulate appetite and calorie intake, and it delays gastric emptying [1]. Wegovy injection and Wegovy 25 mg tablets are the weight-management products and also carry the indication to reduce major cardiovascular events in adults with established cardiovascular disease plus obesity or overweight; only the injection is also approved for noncirrhotic MASH with moderate to advanced fibrosis [1]. Ozempic (injection or tablets) and Rybelsus are type 2 diabetes labels, and Ozempic carries no weight-loss indication [4][5]. The dose numbers below are Wegovy's.

The Wegovy label says it is not recommended in combination with another semaglutide-containing product or any other GLP-1 receptor agonist [1].

Phase 1: the dose escalation

Wegovy injection rises in four-week steps: 0.25 mg for weeks 1 to 4, 0.5 mg for weeks 5 to 8, 1 mg for weeks 9 to 12, 1.7 mg for weeks 13 to 16, then maintenance from week 17 [1]. The label lists 2.4 mg (or 1.7 mg) as the maintenance doses for weight reduction [1].

The tablets keep a different clock: 1.5 mg daily for days 1 to 30, 4 mg for days 31 to 60, 9 mg for days 61 to 90, then 25 mg from day 91 [1]. The tablet label says to take them on an empty stomach in the morning with up to 4 ounces of plain water, swallow them whole, and wait at least 30 minutes before food, drink or other oral medicines [1].

Missed doses depend on the form. The Wegovy injection label says a missed dose can be given when the next scheduled dose is more than 2 days away, and that after 2 or more consecutive missed doses its schedule calls for re-escalation from a lower dose [1]. For the tablets, the label says to skip the missed dose and take the next one the following day [1].

The Ozempic and Rybelsus labels state that the majority of nausea, vomiting and diarrhea reports occurred during dose escalation [4][5].

Phase 2: maintenance and what the weight results look like

Maintenance is the long-term stretch. The recommended Wegovy injection dose for weight reduction is 2.4 mg weekly, or 1.7 mg; adults who tolerate 2.4 mg for at least 4 weeks and need more weight loss can go to a maximum of 7.2 mg weekly [1].

What that produces depends on the trial and the person:

• STEP 1, 1,961 adults without diabetes, 68 weeks: mean weight change minus 14.9% on 2.4 mg versus minus 2.4% on placebo, and 86.4% versus 31.5% lost at least 5% [2].
• STEP UP, 1,407 adults without diabetes, 72 weeks: minus 18.7% on 7.2 mg, minus 15.6% on 2.4 mg, minus 3.9% on placebo [6].
• OASIS 4, 307 adults, oral 25 mg daily: minus 13.6% versus minus 2.2% on placebo, with the primary endpoints measured at week 64 [7].
• STEP 2, 1,210 adults with type 2 diabetes: minus 9.6% on 2.4 mg versus minus 3.4% on placebo [8]. The label notes less weight loss in people with type 2 diabetes than in those without [1].
• STEP 5, 304 adults: minus 15.2% versus minus 2.6% at week 104 [9].

For adults with established cardiovascular disease and obesity or overweight but no diabetes, SELECT followed 17,604 people for a mean 39.8 months: cardiovascular death, non-fatal heart attack or non-fatal stroke occurred in 6.5% on 2.4 mg versus 8.0% on placebo (HR 0.80) [10].

Phase 3: how long the course runs

The label's dosing schedule ends at a maintenance dose, not at a set number of weeks, and the trials ran long: STEP 5 followed people receiving semaglutide 2.4 mg for 104 weeks, with a mean weight change of minus 15.2% versus minus 2.6% on placebo [9]. Semaglutide has an elimination half-life of about one week, and it stays in the body roughly 5 to 7 weeks after the last 2.4 mg or 7.2 mg injection or 25 mg tablet [1].

What happens when the drug stops

Regain after withdrawal has been measured. In a 327-participant off-treatment extension of STEP 1, the semaglutide group had lost a mean 17.3% by week 68 and regained 11.6 percentage points by week 120, about two-thirds of it, leaving a net loss of 5.6% versus 0.1% on placebo; most cardiometabolic improvements moved back toward baseline [3].

STEP 4 asked the same question with a randomized withdrawal design. After a 20-week run-in that produced a mean loss of 10.6%, 803 adults were assigned to continue semaglutide 2.4 mg or switch to placebo for 48 weeks. From week 20 to week 68, weight changed by minus 7.9% on continued treatment and plus 6.9% on placebo [11].

Side effects that change the plan

In pooled trials of 2,116 adults on Wegovy 2.4 mg and 1,261 on placebo, up to 68 weeks, the common reactions were nausea (44% versus 16%), diarrhea (30% versus 16%), vomiting (24% versus 6%) and constipation (24% versus 11%). Any gastrointestinal reaction occurred in 73% versus 47%, and 6.8% versus 3.2% stopped treatment for an adverse reaction, most often nausea, vomiting or diarrhea [1].

The Wegovy label calls for discontinuing treatment if pancreatitis is suspected. It also lists acute gallbladder disease (cholelithiasis 1.6% versus 0.7% and cholecystitis 0.6% versus 0.2% in adult injection trials), acute kidney injury from volume depletion, hypoglycemia when combined with insulin or a sulfonylurea, and a mean heart-rate rise of 1 to 4 beats per minute [1]. The Wegovy, Ozempic and Rybelsus labels carry a boxed warning about thyroid C-cell tumors seen in rodents. Whether semaglutide causes these tumors in humans is unknown [1][4][5]. The Wegovy, Ozempic and Rybelsus labels state a contraindication for a personal or family history of medullary thyroid carcinoma or MEN 2 [1][4][5]. The Wegovy label says to stop at least 2 months before a planned pregnancy [1].

On gastric emptying, the labels say semaglutide is not recommended in patients with severe gastroparesis and list ileus and intestinal obstruction as postmarketing reports; they do not state that semaglutide causes gastroparesis [4][1].