Relenza - Pharma's biggest Flops

Company: GlaxoSmithKline
Year approved: 1999

The Promise: Relenza (zanamivir) was developed by Australian biotech Biota before being licensed to GlaxoSmithKline in 1990. After its approval in 1999, flu pandemic fears began to spread as the avian flu captured the public's attention. As one of only two pandemic flu drugs approved by the FDA--the other being Tamiflu--Relenza was set for megablockbuster sales.

What went wrong: Despite its better efficacy rates compared to Tamiflu, as well as its lower price, Relenza had too many warnings. The powder-form, administered via a "diskhaler," aggravated respiratory problems in some patients. Plus, Tamiflu's pill and liquid systems were approved for patients as young as two years old, while Relenza was approved only for those over seven. Also, Relenza was only approved for use as a treatment for influenza, whereas Tamiflu could be taken as a preventative measure.

But Relenza's sales never matched its competitor's. In 2006, Relenza only gained $13 million in revenue, compared to Tamiflu's $770 million in the first half.

In a show of good will at the start of the H1N1 flu scare, Roche donated 30 million doses of Tamiflu to the World Health Organization stockpile, and the drug was widely touted by agencies and doctors alike as prescription for swine flu.

As Biota's CEO Peter Cook said in a Pharmaceutical Manufacturing interview, "Relenza should be a billion-dollar product." The company sued GSK in 2004 for not marketing Relenza properly, leading to disappointing returns for its shareholders.

Relenza - Pharma's biggest Flops
Read more on

Suggested Articles

Johnson & Johnson and Bayer’s Xarelto is working to reverse a sales slide, and a new indication could help.

AZ's FluMist will be dramatically limited in the U.S. this flu season because of production problems, a spokeswoman said.

To get its $12 billion opioid deal off the ground, Purdue Pharma pushed for a stay on thousands of lawsuits against it. Last week, a judge signed off.