VX-809/VX-661, Vertex

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The drugs: VX-809/VX-661
The disease: Cystic fibrosis
The developer: Vertex
Peak sales potential: $4 billion to $6 billion for the combo franchise with Kalydeco

The scoop: Vertex ($VRTX) made drug history the first time when it successfully developed a new standard of care for hepatitis C, Incivek. But now that that blockbuster is about to be relegated to history by a new generation of hep C drugs, it's the cystic fibrosis franchise that gets all the attention. And for good reason.

Vertex's Kalydeco demonstrated its ability to improve lung function--which typically worsens over time--in CF patients with a specific mutation which only covers about 4% of the patient population. Priced close to $300,000 a year, though, the therapy generated substantial sales quickly. And now VX-809 is being paired with Kalydeco in a late-stage bid to greatly expand its market reach, with a follow-up combo program demonstrating the potential to expand Vertex's reach to the vast majority of patients.

Early this year the Boston-based developer laid out plans for a late-stage program that will enroll 1,000 patients age 12 and older at 200 sites. Patients have two copies of the F508del mutation in the CFTR gene, which covers about half of the 70,000 CF patients worldwide. And the company has also set up a safety and pharmacokinetics study for a group of 6- to 11-year-olds to be used for registration in the U.S. and food for discussion with European regulators.

Vertex--a longtime collaborator with the Cystic Fibrosis Foundation--did itself a tremendous amount of good earlier this year with a positive mid-stage readout for a combination of Kalydeco and VX-661, a follow-up match-up with a CFTR corrector molecule. And it won one of the FDA's first "breakthrough" drug designations for the Kalydeco/VX-809 combo.

Vertex has an outstanding executive team, covering CEO Jeffrey Leiden and their brilliant R&D chief Peter Mueller. By turning the spotlight to CF, the biotech has managed to avoid much of the collateral damage to be expected with setbacks on its attempt to mount a next-gen approach to hep C.

For more:
Special Report: Top 15 Drug Launch Superstars - Kalydeco | Top 20 orphan drugs by 2018 - Kalydeco
Vertex skyrockets on positive Ph2 combo study in cystic fibrosis
Vertex's new data on CF drug cocktail doesn't disappoint