Press Release

SAN FRANCISCO, Aug. 7, 2012 /PRNewswire/ -- Nektar Therapeutics (NASDAQ:NKTR) announced today the start of a Phase 2 study of etirinotecan pegol in patients with bevacizumab (Avastin)-resistant high-grade glioma being conducted at Stanford Cancer Institute. The Phase 2 study is an investigator-sponsored trial being conducted under the direction of Lawrence Recht, M.D., Professor of Neurology and Neurosurgery, with co-investigators Seema Nagpal, M.D. and Pamela Kunz, M.D.

"Patients with bevacizumab-resistant high-grade glioma currently have little to no treatment options to help them manage their disease," said Dr. Recht. "We know that the mechanism of topoisomerase I inhibition has resulted in anti-tumor activity in gliomas in the past.  As a result, we are interested in evaluating etirinotecan pegol, this new targeted topoisomerase I inhibitor, which provides sustained exposure of drug metabolite to tumor cells."

The primary endpoint of the Phase 2 study is the six-week progression free survival (PFS) rate. Secondary endpoints include survival from time of first etirinotecan pegol infusion, overall survival from date of pathologic diagnosis or confirmation of high-grade glioma, and the safety profile of etirinotecan pegol in patients with bevacizumab-resistant high-grade glioma. The open label, single-arm trial is expected to enroll approximately 20 patients who will receive etirinotecan pegol once every three weeks as monotherapy.

"Etirinotecan pegol has demonstrated promising results in drug-resistant solid tumors, such as advanced and heavily pre-treated breast and ovarian cancers," said Robert Medve, M.D., Senior Vice President and Chief Medical Officer of Nektar Therapeutics.  "Recognizing the high unmet need in glioma, we are very pleased to support Dr. Recht and his colleagues with this study of single-agent etirinotecan pegol in this setting."

About High-Grade Glioma

High-grade gliomas are the most common and most aggressive primary brain tumors. Prognosis for patients with high-grade gliomas remains poor with estimated median survival of 12 to 18 months. Recurrence after initial therapy with temozolomide and radiation is nearly universal. Since May 2009, the majority of patients in the U.S. with an initial recurrence of high-grade glioma receive bevacizumab. Bevacizumab has response rates from 32-62% and has improved median overall survival in patients with recurrent high-grade gliomas.¹ However, the response is short lived and nearly 100% of patients eventually progress despite bevacizumab. No chemotherapeutic agent administered following progression through bevacizumab has made a significant impact on survival.^2,3 Patients progress to death within 1-5 months after resistance develops.^3,4 Patients with high-grade gliomas who have progressed through bevacizumab represent a population in dire need of new therapies.

About Etirinotecan Pegol

Etirinotecan pegol is a unique, targeted topoisomerase I inhibitor designed for prolonged tumor cell exposure. Etirinotecan pegol is believed to penetrate the vasculature of the tumor environment more readily than normal vasculature, increasing the concentration of active drug within tumor tissue to enhance anti-tumor activity.  The BEACON study is a Phase 3 clinical study currently evaluating etirinotecan pegol for the treatment of metastatic breast cancer.   In addition, etirinotecan pegol is also being tested as a single agent in a Phase 2 clinical trial in patients with platinum-refractory/resistant ovarian cancer, a Phase 2 clinical trial in patients with colorectal cancer with KRAS mutations after failing first- line therapy, and a Phase 1 clinical trial evaluating etirinotecan pegol in combination with 5-FU and leucovorin therapy.

About Nektar

Nektar Therapeutics is a biopharmaceutical company developing novel therapeutics based on its PEGylation and advanced polymer conjugation technology platforms.  Nektar has a robust R&D pipeline of potentially high-value therapeutics in oncology, pain and other therapeutic areas. In the area of pain, Nektar has an exclusive worldwide license agreement with AstraZeneca for naloxegol (NKTR-118), an investigational drug candidate, which is being evaluated in Phase 3 clinical studies as a once- daily, oral tablet for the treatment of opioid-induced constipation.  This agreement also includes NKTR-119, an earlier stage development program that is a co-formulation of naloxegol and an opioid.  NKTR-181, a novel mu-opioid analgesic candidate for chronic pain conditions, is in Phase 2 development in osteoarthritis patients with chronic knee pain.  NKTR-192, a novel mu-opioid analgesic in development to treat acute pain is in Phase 1 clinical development.  In oncology, etirinotecan pegol (NKTR-102) is being evaluated in a Phase 3 clinical study (the BEACON study) for the treatment of metastatic breast cancer and is also in Phase 2 studies for the treatment of ovarian and colorectal cancers.

Nektar's technology has enabled eight approved products in the U.S. or Europe through partnerships with leading biopharmaceutical companies, including Affymax's OMONTYS® for anemia, UCB's Cimzia® for Crohn's disease and rheumatoid arthritis, Roche's PEGASYS® for hepatitis C and Amgen's Neulasta® for neutropenia.  Additional development-stage products that leverage Nektar's proprietary technology platform include Baxter's BAX 855, a long-acting PEGylated rFVIII program, which is in Phase 1 clinical development.

Nektar is headquartered in San Francisco, California, with additional operations in Huntsville, Alabama and Hyderabad, India.  Further information about the company and its drug development programs and capabilities may be found online at http://www.nektar.com.

SOURCE Nektar Therapeutics