Nektar Therapeutics has presented positive Phase II study results of NKTR-102 in patients with metastatic breast cancer.

NKTR-102, a topoisomerase I inhibitor, is designed using Nektar’s proprietary polymer conjugate technology and is being developed in multiple tumour settings.

USC Norris Comprehensive Center Clinical Medicine associate professor Agustin Garcia said that NKTR-102 exhibits a high response rate and excellent clinical benefit rate in patients with metastatic breast cancer, and that anti-tumour activity is maintained in each of the poor prognosis subsets within the study.

“The data from the Phase II study also shows highly promising progression-free survival of 5.3 months and overall survival of 13.1 months in the every three week dose schedule, which was also very well-tolerated,” Garcia added.

The randomised two-stage study of single-agent NKTR-102 evaluated two 145mg/m² dose schedules of NKTR-102, every two weeks (q14d) and every three weeks (q21d), in 70 metastatic breast cancer patients.

In the trial, NKTR-102 achieved a confirmed objective response rate by RECIST of 29%, while 71% of patients showed no tumour progression.

The company also plans to conduct a Phase III clinical trial of NKTR-102 in 840 metastatic breast cancer patients who have had prior treatment with anthracycline, taxane and capecitabine in either the adjuvant or metastatic setting.

The primary endpoint of the breast cancer outcomes with NKTR-102 study, expected to begin in December 2011, will be overall survival and secondary endpoints will include progression-free survival and overall response rate.