CAMBRIGE, Mass. ( TheStreet) -- Vertex Pharmaceuticals ( VRTX) shares are soaring 60% to $84.87 Friday morning following an announcement last night that its cystic fibrosis drug Kalydeco combined with an experimental drug VX-661 significantly improved the lung function of patients in a mid-stage clinical trial. Analysts are rushing to upgrade and slap triple-digit price targets on Vertex because it now appears more likely that the company's cystic fibrosis drug franchise will prove effective for a large swath of the 70,000 people with the genetic lung disease worldwide. Peak sales could easily top $5-6 billion. Last May, when Vertex released interim results from its combination therapy for cystic fibrosis, I wrote a column explaining why investors should look at Vertex as the next Gilead Sciences ( GILD). Like Gilead dominates HIV therapy (and perhaps hepatitis C therapy soon), Vertex will now dominate cystic fibrosis. I've reprinted this column below because the "Vertex is the next Gilead" thesis is now stronger than ever. Originally published on May 7. Vertex Pharmaceuticals is the next Gilead Sciences. You think I'm reaching? Okay, then Vertex is the next Alexion Pharmaceuticals. Either way, the big move higher in Vertex's stock price Monday, spurred by the release of strong cystic fibrosis data, is totally justified and likely undervalues the company going forward. Vertex shares rose $20.71, or 55%, to $58.12 Monday following the announcement that two drugs -- the experimental VX-809 and currently marketed Kalydeco -- significantly improved lung function in patients with the most common genetic mutation causing cystic fibrosis. Monday's data were the result of an interim analysis from a relatively small number of patients, so without a doubt, caution is warranted and the benefit seen from the two-drug therapy must be maintained and confirmed in a larger, pivotal trial. But if we assume VX-809 and Kalydeco are approved, the revenue numbers for Vertex get very, very large: $4 billion a year in peak cystic fibrosis sales is a floor. The company's cystic fibrosis drugs could top $6-7 billion a year, easily. There are 70,000 cystic fibrosis patients worldwide and Vertex could easily treat more than half of them with Kalydeco or the VX-809-Kalydeco combination. A year of Kalydeco therapy today costs $294,000 -- not uncommon for orphan disease pricing. Vertex may cut the price of the two-drug regimen but even if you assume $200,000 per year, the sales potential is enormous.