Shares of Synlogic Inc. SYBX, +4.77% sank 9.3% toward a record low in premarket trading Tuesday, after the biotechnology company said it has discontinued the development of SYNB1020 for the treatment of hyperammonemia following disappointing trial results. The company said that data from a phase1b/2a study showed that while SYNB1020 was well tolerated in patients with cirrhosis, there was no evidence of blood ammonia lowering or changes in other exploratory endpoints relative to placebo. “Moving forward, we will focus our resources on advancement of SYNB1618 for the treatment of phenylketonuria, SYNB1891 for the treatment of solid tumors and several new programs in early development,” said Chief Executive Aoife Brennan. The stock has tumbled 31.1% year to date through Monday, while the iShares Nasdaq Biotechnology ETF IBB, +1.13% has gained 10.1% and the S&P 500 SPX, +1.21% has advanced 16.6%.