Karyopharm Therapeutics Inc. has expanded its lease at Wells Center in Newton.

Karyopharm, a clinical-stage pharmaceutical company, is now leasing 46,167 square feet of office and laboratory space on the second and third floors at 75 – 95 Wells Ave., a 16,234-square-foot expansion.

Transwestern | RBJ’s John Lashar, Jon Varholak and Ron Friedman, partners, along with Managing Partner and Northeast Market Leader Steve Purpura represented Karyopharm in the expansion. Transwestern | RBJ also advised Karyopharm when it selected the Newton location in May 2014 after outgrowing its Natick facility. Normandy Real Estate Partners, the owner of Wells Center, was represented by Alex Dauria and Brendan Cohn of JLL.

“Our goal is to foster scientific creativity with pioneering technologies and developmental approaches within an innovative culture that will accelerate first-in-class small molecule modulators of nuclear transport into effective therapeutics for life threatening conditions,” Justin Renz, executive vice president and chief financial officer of Karyopharm, said in a statement. “Our expanded location in Newton has enabled us to enhance our collaboration and communication research and development efforts. A factor in our choosing of Wells Center last year was its expansion potential.”