Sana Biotechnology went public before testing any treatments in people. The cell and gene therapy startup won't launch clinical trials for at least a year. Noted life sciences VCs Flagship Pioneering and Arch Venture Partners were its biggest shareholders pre-IPO. Cell and gene editing startup Sana Biotechnology's shares jumped more than 40% on its first day of trading, making one of its investors' stakes worth more than $1.5 billion. The company sold 23.5 million shares at $25 apiece Thursday. Its stock price was up 40.40% at the end of the first day of trading, closing at $35.10 per share. Sana will have about 185 millions shares outstanding after the IPO, valuing the company at $6.5 billion.