Eli Lilly & Co. (NYSE:LLY) shares were on a tear this week, thanks to the company's strong quarterly results and positive clinical readout from Novo Nordisk A/S (NYSE:NVO), which has a rival offering.

Former hedge fund manager Whitney Tilson in his firm’s Empire Financial Research newsletter weighed in on the stock rally. He recalled his comments from September 2022 in which he discussed weight-loss drugs, calling them “nothing short of miraculous.”

Lilly's Mounjaro seems to have fewer side effects and is most efficacious in terms of weight loss, he said then.

Recalling the comments, Tilson said, "Alas, while I highlighted the stock of Mounjaro's maker Eli Lilly (LLY), I didn't pound the table on it." Instead, he had said then he would stay on the sidelines and hope for a pullback.

Tilson evidently regretted the lost opportunity. “I should have followed my instincts and paid up for the stock, as it’s up 68% since then after yesterday’s [Tuesday’s] 15% spike in the wake of blowout earnings and this huge news.”

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Referring to positive clinical results from Novo Nordisk, Tilson said the ability of the company's weight-loss drug Wegovy to significantly reduce a major cardiac event should dramatically increase the usage of these weight-loss drugs.

This is because of the increasing willingness to take the drug and the increased probability of payors, both governments and health insurers, providing coverage, he added.

“While Wegovy is made by Novo Nordisk (NVO), I have no doubt that the similar studies underway for Mounjaro will show similar, if not greater, results,” Tilson said.

Lilly closed Thursday’s session down 0.93% at $521.34, according to Benzinga Pro data.

Read Next: Obesity Drug Wegovy Sales Jump 365% In H1 As Novo Nordisk Reports Solid Results, Raises FY23 Guidance