NEEDHAM, Mass. (AP) — Cancer drug developer Celldex Therapeutics Inc. reported a wider loss for its second-quarter due to increased research and development spending.

The company, based in Needham, Mass., is trying to develop a number of drugs to treat cancer and other difficult-to-treat diseases based on antibody and immunotherapy-based treatments.

Celldex on Friday reported a loss of $13.8 million, or 23 cents per share, for the period that ended June 30. That's compared with a loss of $10.2 million, or 27 cents per share, a year earlier.

Revenue increased slightly to $2 million due to contract and grants revenue tied to vaccine research.

Analysts surveyed by FactSet expected a loss of 10 cents per share on revenue of $2.2 million.

The company was weighed down by $11.1 million in research and development expenses, versus the $7.2 million it spent in the prior year.

Celldex spent more on clinical trials for drugs that it is developing for potential treatment of brain tumors, which was offset by lower contracted research and contract manufacturing expenses. The company is in the midst of opening clinical sites to support Phase 2 and Phase 3 studies of the drugs.

Shares fell 15 cents, or 3.2 percent, to $4.60 in afternoon trading. Its shares have traded in a 52-week range of $2.05 to $5.72.