Arrowhead Research Corp. late Wednesday reported a narrower fourth quarter loss, largely due to the Pasadena biotech having more shares outstanding than a year earlier.

After the markets closed Wednesday, the RNAi therapeutics company reported a net loss of $31.1 million (-$1.30 a share) for the quarter ended Sept.30, compared with net loss of $21.1 million (-$1.90) in the same period a year earlier. It reported no revenue in the quarter.

Arrowhead’s drug platform seeks to fight disease by blocking the action of genes that contribute to particular diseases. The company has no products on the market, but has seen great interest from investors due to its lead drug candidate, ARC-520, which fights chronic Hepatitis B virus. ARC-520 is in early-stage clinical trials.

The company’s share price has soared more than 300 percent since the beginning of the year. Shares on Wednesday earlier closed up 39 cents, or 4.5 percent, to $9.14 on the Nasdaq.