FROM THE PR NEWSWIRE: New drug may improve response for women whose tumors have not responded to taxanes.

SAN CARLOS, Calif., June 9 /PRNewswire-FirstCall/ — Nektar Therapeutics (Nasdaq: NKTR) today announced positive preliminary initial results from a two-stage Phase 2 clinical study evaluating single-agent NKTR-102 in women with advanced/metastatic breast cancer patients who have received a prior taxane. The increased use of taxanes in breast cancer often renders tumors resistant to these drugs by the time the disease recurs, thereby underscoring the urgent need for new treatment options with novel mechanisms of action for metastatic disease.

The single-agent NKTR-102 study recently completed enrollment with a total of 70 patients with metastatic breast cancer. A significant majority of the women had been treated with prior anthracycline/taxane with or without capecitabine. Of the 70 patients, 66 patients are currently evaluable per RECIST for the imaging-based primary endpoint of objective response rate. Confirmed and unconfirmed RECIST responses were 21% (14/66) overall for single-agent NKTR-102, with 18% (6/33) for the q14d dose regimen and 24% (8/33) for the q21d dose regimen. There are a significant number of patients in the study still on therapy with NKTR-102.

“This is a very promising result in patients with metastatic breast cancer who have failed prior taxanes and in most cases, prior anthracyclines,” said Prof. Ahmad Awada, Head of the Gynecologic Oncology Clinic at the Institut Jules Bordet in Brussels, Belgium. “I have patients who have not responded to any prior therapy but who have experienced a good response to NKTR-102. These data are quite encouraging, and NKTR-102 should be taken forward as a single agent and in combination therapy in patients with difficult-to-treat disease such as triple-negative breast cancer and anthracycline/taxane failures.”

Of the 70 patients enrolled in the study, approximately 85% had received prior anthracycline/ taxane, either with or without capecitabine therapy. The drug has been well-tolerated to-date. The most commonly observed grade 3 or grade 4 side effects in the study to date (every 14 day/every 21 day dose schedule) were diarrhea (14%/6%) and neutropenia (9%/6%). There were low rates of alopecia observed with single-agent NKTR-102, with only a small number of women experiencing Grade 2 alopecia.

“We are highly encouraged by the compelling preliminary activity observed to-date in the patients from our study,” said Lorianne Masuoka, M.D., Senior Vice President and Chief Medical Officer. “This, combined with our recent results presented at the 2010 ASCO meeting for single-agent NKTR-102 in women with platinum-resistant and refractory ovarian cancer, make us very excited about the future of NKTR-102 as a novel anti-cancer agent.”

About the Study

The Phase 2 study is evaluating two dose regimens (q14 day and q21 day) of single-agent NKTR-102 in women with metastatic breast cancer. The study employs a two-stage design, with 40 patients in the first stage and 30 patients in the second stage. Secondary endpoints of the Phase 2 study include progression-free survival and safety.

About Metastatic Breast Cancer

Breast cancer is one of the most common cancers among every major ethnic group of women in the United States. The chance of developing invasive breast cancer at some time in a woman’s life is a little less than 1 in 8 (12%). According to the American Cancer Society, nearly 200,000 new cases of invasive breast cancer were diagnosed in women in 2009. Anthracyclines and taxanes are the most active and widely used chemotherapeutic agents for breast cancer, but the increased use of these agents at an early stage of disease often renders tumors resistant to these drugs by the time the disease recurs, thereby reducing the number of treatment options for metastatic disease. Drugs used to treat patients who progress following AT treatment can be as high as 20-30%; however, resistance develops rapidly and new agents with different mechanisms of action, such as topoisomerase I-inhibitors, are needed to allow novel ways to overcome the problem of drug resistance.(1) There are currently no FDA-approved topoisomerase-I inhibitors to treat breast cancer.

About NKTR-102

Nektar is developing NKTR-102, a topoisomerase I inhibitor-polymer conjugate with reduced peak concentrations and a continuous concentration profile. NKTR-102 was invented by Nektar using its advanced polymer conjugate technology platform, and is the first oncology product candidate to leverage Nektar’s releasable polymer technology platform.

In addition to the fully-enrolled Phase 2 studies in platinum-resistant ovarian cancer and metastatic breast cancer, NKTR-102 is also being tested in a separate Phase 2 clinical trial in patients with second-line colorectal cancer and a Phase 1 clinical trial of NKTR-102 evaluating it in combination with 5-FU therapy.

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