Significant Anti-Tumor Activity of NKTR-102 in Patients With Refractory Solid Tumors; Interim Data Published in ASCO 2008 P...( Nektar's Technology Enables First-Ev...),Health

Nektar's Technology Enables First-Ever PEGylation of a Small Molecule with

Demonstrated Therapeutic Activity

SAN CARLOS, Calif., May 16 /PRNewswire-FirstCall/ -- Nektar Therapeutics (Nasdaq: NKTR) announced initial results today from a Phase 1 study of NKTR- 102, PEGylated irinotecan. The data shows significant anti-tumor activity in patients with refractory solid tumors. The study also demonstrates that Nektar's small molecule PEGylation technology produced an increase in SN38 exposure that was up to six-fold higher than the exposure previously reported with irinotecan at equivalent doses. SN38, a topoisomerase I inhibitor, is the active metabolite of irinotecan.

The ASCO abstract reports interim data on 27 of 32 patients in the first of three dose schedules from the Phase 1 trial.(1) Results for the first schedule (weekly x3 q4 weeks) found anti-tumor activity in 7 out of the total 32 patients evaluable for efficacy. Partial responses were confirmed in three patients, or 10% (greater than 30% tumor regression per RECIST), and other evidence of anti-tumor activity was confirmed in four patients, or 12% (tumor regression by more than 15% but less than 30% per RECIST, or significant biomarker evidence).

"This significant anti-tumor activity in a number of patients whose tumors have progressed on prior therapies makes NKTR-102 one of the most promising cancer drugs I have ever studied," said Daniel D. Von Hoff, M.D., lead Phase 1 investigator for NKTR-102, Physician-in-Chief at the Translational Genomics Research Institute and Chief Medical Officer for the Scottsdale Clinical Research Institute at Scottsdale Healthcare.

Nektar's proprietary PEGylation technology can enhance the properties of t
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