A 60-year-old with long-standing obesity and type 2 diabetes controlled on metformin presents with recent weight gain and rising A1c despite medication. Evaluate which next-step strategy is most justified, considering pathophysiology.

Prescribe only insulin without lifestyle advice because lifestyle modification never affects glycemic control after age 50 and medications are ineffective.

Intensify therapy with addition of an agent that improves insulin sensitivity (eg, GLP-1 receptor agonist or SGLT2 inhibitor if appropriate) and concurrently implement structured weight-loss interventions, because progressive insulin resistance and beta-cell stress likely explain worsening glycemia.

Refer for immediate pancreatic transplant because any loss of control on metformin indicates complete beta-cell loss identical to type 1 diabetes.

Discontinue all medications immediately and replace with a high-carbohydrate diet to stimulate beta cells into normal function, since drug exposure causes progressive diabetes by suppressing endogenous insulin.