TRENTON, N.J. – Swiss drugmaker Roche Holding AG said it will close its former U.S. headquarters, a sprawling facility where the groundbreaking drugs Valium and interferon were invented.

The move announced last week is part of a consolidation of research and development programs that will eliminate 1,000 jobs and shut down the site in Nutley, N.J., by the end of 2013.

Nutley served as Roche’s U.S. headquarters for marketing, sales and administration, plus the base for numerous research programs, from 1929 until 2009. Roche bought biotech drugmaker Genentech that year and transferred headquarters operations to Genentech’s base in South San Francisco, Calif.

The Basel, Switzerland-based maker of influenza treatment Tamiflu said the research and drug development conducted in Nutley will be consolidated with operations in Basel and Schlieren, Switzerland, and in Penzberg, Germany. That will result in about 80 more jobs in Switzerland and Germany.

At its peak about 10 years ago, the 119-acre Nutley site had about 10,000 employees, including scientists researching potential new treatments for cancer, hepatitis C and arthritis and other inflammatory disorders. The workforce dropped to about 5,000 people when Roche integrated Genentech and shifted many Roche workers to California.

Roche spokesman Daniel Grotzky in Switzerland said some early-stage arthritis research at Nutley that wasn’t very promising will be eliminated, and other arthritis projects will continue at Genentech. Selected hepatitis research projects will be shifted to Switzerland, and research on injected cancer treatments will move to Penzberg.

He wouldn’t say how much money the closure would save but said savings would be shifted toward ongoing and new drug testing, with the number of Roche’s mid- and late-stage drug tests expected to jump 20 percent in 2013 compared to this year.

Darien Wilson, a spokeswoman at Nutley, known as Hoffmann-La Roche Inc., said staff will be told in mid-August whether they will lose their jobs or can transfer to a new research center Roche is planning for somewhere on the East Coast. That site, which will employ about 240 people, will support patient testing of experimental drugs and coordinate with the Food and Drug Administration and university research partners. Roche hopes to identify a location by September.