The Los Angeles Business Journal’s index of largest local public companies fell for the week.

The weighted LABJ Stock Index closed down 3.7 percent to 181.97 for the trading week ended April 11. Decliners outpaced gainers 132 to 22, with seven companies unchanged.

The biggest decliner was Puma Biotechnology Inc., falling 27 percent to $76.17. The Westwood drug developer reported clinical trial results for its experimental breast cancer drug that disappointed investors.

Several other small biotech companies were among the biggest decliners, in line with the larger industry. Pasadena biotech Arrowhead Research Corp. fell 23 percent to $13.13 despite a lack of market-moving news. CytRx Corp., which fell 19 percent to $3.19, said it began an important, late-stage trial of its lead cancer drug candidate. Xencor Inc. fell 9.6 percent to $9.59, even though the Monrovia drug developer said it received a milestone payment from a partner.

Herbalife fell 13 percent to $51.48 after the Financial Times reported that the U.S. Department of Justice and the FBI were investigating the L.A. supplements company.

Among the biggest gainers was RadNet Inc., which rose 20 percent to $$4.07. The Los Angeles medical imaging chain announced an expanded agreement with Kennedy Health System in southern New Jersey.

Jakks Pacific Inc. rose 15 percent to $8.28. BMO Capital Markets raised its rating on shares of the Malibu toymaker to “outperform”.

Rentech Inc. rose 11 percent to $2.14. The Los Angeles company said that a Blackstone Group unit would invest $150 million in its wood fiber business.