It’s attainable that tirzepatide is barely simpler as a result of it’s a twin receptor agonist. Along with GLP-1, it additionally prompts receptors of GIP, one other hormone concerned in regulating blood sugar and urge for food. However McGuire says GIP isn’t effectively understood, and it’s not clear whether or not the addition of GIP is driving the elevated weight reduction or if tirzepatide is simply higher at activating GLP-1. “We simply don’t have a solution to unravel that biology proper now,” he says.
That hasn’t stopped pharma firms from pursuing GIP as a goal. Viking Prescription drugs can be creating a drug that prompts each the GLP-1 and GIP receptors. The San Diego firm is testing each an injectable and capsule kind. In a trial of the injectable model, individuals misplaced practically 15 p.c of their weight over 13 weeks. And information launched in March from an early-stage trial confirmed that individuals who took Viking’s day by day capsule model misplaced round 5 p.c of their weight on common in only a month.
Novo Nordisk, Eli Lilly, and Pfizer are all engaged on their very own GLP-1 tablets. Some sufferers might desire taking a day by day capsule over a weekly injection. Drugs are additionally simpler to fabricate than the injector pens used to manage Wegovy and Zepbound. The pens additionally must be refrigerated.
“All of that makes these medicine dearer,” says Laura Davisson, director of the load administration program on the West Virginia College Well being System. “If we may get oral variations available on the market, perhaps the costs would come down.”
Amgen, in the meantime, thinks a much less ceaselessly taken medicine may very well be handy for some sufferers. The corporate is engaged on an injectable drug known as MariTide that may be given simply as soon as a month. The drug additionally targets GLP-1 and GIP, however as a substitute of stimulating GIP receptors, MariTide blocks them. It’s not solely clear why each stimulating and blocking these receptors appears to advertise weight reduction.
Amgen’s strategy relies on analysis displaying that mice that lack GIP, in addition to individuals with mutations on this receptor, have decrease physique weight. In outcomes printed in February, individuals taking MariTide in an early-stage trial misplaced as much as greater than 14 p.c of their physique weight in 12 weeks.
Eli Lilly is hoping to make an much more potent drug than Zepbound by including a 3rd mechanism concerned in weight reduction. It’s engaged on an investigational drug dubbed retatrutide that targets the receptors for GLP-1, GIP, and glucagon, the latter of which may help break down fats shops. In trial information printed final 12 months, retatrutide helped individuals lose greater than 17 p.c of their physique weight, or 41 kilos, after 24 weeks. At 48 weeks, individuals had misplaced a median of 24 p.c of their physique weight, or about 58 kilos—greater than every other drug available on the market.
“Now we have not seen outcomes like this earlier than in a trial of lower than one-year period with an anti-obesity medicine,” stated Ania Jastreboff, an endocrinologist and weight specialist on the Yale College of Medication throughout a press convention final 12 months on the American Diabetes Affiliation annual assembly.