Sep. 22, 2009 (PR Newswire) --

BERLIN and SAN CARLOS, Calif., Sept. 22 /PRNewswire-FirstCall/ -- Nektar Therapeutics (Nasdaq: NKTR) presented favorable data today on lead oncology program, NKTR-102, demonstrating encouraging Phase 1 and preclinical anti-tumor activity of the investigational compound in ovarian cancer. These data were presented at the European CanCer Organisation (ECCO) and the European Society for Medical Oncology (ESMO) 2009 Joint Multidisciplinary Congress in Berlin, Germany.

"As highlighted in our data presented today at ECCO/ESMO, we continue to see encouraging signs suggesting that NKTR-102's improved pharmacokinetics could result in an enhanced therapeutic profile," said Lorianne Masuoka, M.D., Chief Medical Officer. "We are also pleased with the rapid enrollment of the first stage of our Phase 2 clinical study in platinum-resistant ovarian cancer. Although many patients are not yet evaluable for response, we have already achieved a sufficient number of confirmed responses to open the second stage for both regimens in the study earlier than anticipated. This important new compound may offer a valuable new treatment option to overcome chemo-resistance in patients with recurrent ovarian cancer."

NKTR-102 is a novel prodrug of irinotecan that was designed using Nektar's proprietary small molecule advanced polymer conjugate technology platform. Nektar's proprietary technology is being used to significantly improve the half-life and potentially enhance the therapeutic profile of important chemotherapeutic agents and also to create novel, oral small molecule drug candidates across multiple therapeutic areas.

In the preclinical studies presented today, NKTR-102 was evaluated at three dose levels and compared to three equivalent dose levels of irinotecan in a platinum-resistant 2780 ovarian cancer mouse model. NKTR-102 showed clear superiority over irinotecan at all dose levels, with 100% of animals demonstrating partial or complete tumor regression with NKTR-102 compared to only 1 of 10 animals with a partial response at the highest irinotecan dose. NKTR-102 was also better tolerated than irinotecan at all doses tested.

Data were also presented on patients with recurrent ovarian cancer from the Phase 1 dose-escalation study of single agent NKTR-102. Of five patients with ovarian cancer in the study, two were evaluable for efficacy. Both patients showed significant anti-tumor activity, including tumor reductions of up to 37% and a decrease in CA-125 marker levels of up to 80%. These patients had failed multiple prior therapies and had progressed following prior platinum-based therapy.