Traders at a securities brokerage look at changing stock prices. (Photographer: Jerome Favre/Bloomberg)

Former Stock Market Darling Loses $4 Billion in One Week

(Bloomberg) -- No other stock has been on a roller-coaster ride like this one, at least not over the past week.

SanBio Co., once a darling to investors thanks to its highly anticipated traumatic brain injury medicine, has wiped out more than $4 billion in value over the past week. The company on Jan. 29 announced a surprise failure in a key trial for the drug. The shares were untraded for a week on a glut of sell orders, before exchanging hands for the first time on Tuesday and fell for a record five-day nosedive of 78 percent.

The stock, which had the largest weighting of almost 14 percent on the Tokyo Stock Exchange Mothers Index as recently as last Tuesday, has tumbled to the No. 5 spot with a current weighting of a little over 3 percent. No other Japanese stock recorded a decline as steep as SanBio’s in the period, although Sumitomo Dainippon Pharma Co., SanBio’s partner in the SB623 drug, came close with a 31 percent slide.

On SanBio, “I really find it hard to see any upside scenario for the stock, other than a very short-term bounce after such a huge decline, given it’s got zero growth drivers now SB623 is gone,” said Andrew Jackson, head of Japanese equities at Soochow CSSD Capital Markets. “They will try and develop the Japan market but it’s not looking very exciting for them.”

Former Stock Market Darling Loses $4 Billion in One Week

The two companies disclosed in a statement last week they failed to reach a necessary target, or a primary endpoint, for the drug’s latest trial as a post-stroke treatment. The companies will “consider future development plans” for the drug, based on additional analyses of the study results. This was a letdown especially after the drug succeeded in a different trial in November, snowballing expectations for the stock.

“This is a big retail name and I’m sure some of them won’t resist a punt on something that’s been limit down for so long,” Jackson said, suggesting the possibility of a near-term rebound. But he sounded less optimistic over the longer term.

“It’s more like a shell of a company now,” he said. “I mean all the revenue projections for it were based purely on SB623. And now that’s gone.”

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