Obesity isn't a temporary problem, practically every weight loss solution fails at 2-5 year outlooks. If this drug has to be taken for decades it's still better than decades of obesity.
Any condition that is not chronic is temporary by definition. It doesn't matter if it can be cured in 5 years or 20. If a person is dependant on a drug to maintain health, then they have a chronic condition.
This is exactly why I italicized usually.