Court invalidated Eli Lilly's Prozac patent in 2000, beginning a long stock decline

Eli Lilly's shares fell $31 in a matter of hours on Aug. 9, 2000, after a federal appeals court invalidated the company's patent on the antidepressant Prozac ^[1]. The ruling ended Lilly's exclusive hold on the drug, and longtime executives at the Indianapolis company still recalled the day years later ^[1].

Lilly stock had closed at an all-time high of $108 the day before ^[1]. The Prozac decision was one of several setbacks that sent the shares into a prolonged slide; they bottomed at $29 during the financial crisis of 2008 ^[1].

The company spent the following decade bracing for more of the same. As of 2010, four of its largest products were headed toward the end of patent protection: the cancer drug Gemzar, the schizophrenia treatment Zyprexa, the antidepressant Cymbalta and the osteoporosis medicine Evista ^[1]. Generic competition was expected to follow each one ^[1]. In 2009, those four medicines brought in $10.4 billion of Lilly's $21.8 billion in sales ^[1]. Not everyone believed the company could absorb those losses on its own. "It's a very strange position they're taking, considering what they're facing," Standard & Poor's analyst Herman Saftlas told Reuters in 2010 ^[1].

John Lechleiter, a longtime Lilly executive, became CEO in 2008 with the job of preparing the company for those expirations while its labs raced to bring new drugs to market ^[1]. He told analysts Lilly had worked to avoid another boom-and-bust cycle like the one that marked the previous 10 years ^[1]. Chief Financial Officer Derica Rice said on a Jan. 31 conference call that the company had delivered on the financial commitments it made five years earlier, advanced its pipeline and built what he called a sustainable research engine ^[1]. Lilly kept its quarterly dividend at 49 cents a share ^[1].

Company sales peaked at $23.3 billion in 2011 and fell to a seven-year low of $19.6 billion in 2014 ^[1]. J.P. Morgan projected they would reach $25.6 billion by 2020 ^[1]. By early 2015 the shares had climbed 45 percent since October 2013, back above $70, a range they had not traded in for 11 years ^[1]. Analysts credited new drug launches, a $5.4 billion purchase of Novartis Animal Health and a pipeline they viewed more favorably ^[1]. UBS analyst Marc Goodman wrote in a Jan. 31 report that Lilly could post low-to-mid-teens earnings-per-share growth over the next five years, near the best in the sector ^[1], and Bernstein analyst Tim Anderson said sentiment had slowly turned more positive, calling the company a pipeline-driven return to growth ^[1]. Neither analyst assumed success from the company's Alzheimer's program, described as perhaps the biggest unknown, with a high chance of failure and a large payoff if it worked ^[1].

Why it matters for patients

Patent protection is the clock that decides when a brand-name medicine can face cheaper generic copies ^[1]. Invalidating Lilly's Prozac patent opened the door to that competition for one drug, and the later expirations of four other products did the same ^[1].

Nothing in this account sets out patent dates, generic timelines or price projections for semaglutide, tirzepatide or orforglipron. Those have not been reported here. The figures above describe Prozac and four other Lilly medicines, not GLP-1 drugs.

The episode also shows how much of a drugmaker's planning is built around exclusivity clocks. While Lilly absorbed the lost revenue, it cut costs and held its dividend steady ^[1], and management said it wanted to avoid a repeat of that cycle ^[1]. Which treatments a company chooses to develop, and when rivals can sell copies of them, sits behind the options patients and their doctors face.