14 January 2010 - US biopharmaceutical company Nektar Therapeutics (NASDAQ: NKTR) reported on Tuesday preliminary results from the first stage of a two-stage Phase II study evaluating NKTR-102 in women with platinum-resistant ovarian cancer.

In the first stage of the study, 39 patients enrolled with platinum-resistant disease were evaluable for the primary endpoint of overall response rate using Gynecologic Cancer InterGroup (GCIG) criteria, i.e., a combination of response by tumour imaging (RECIST) and/or ovarian cancer biomarker (CA-125) criteria.

The first stage of the NKTR-102 Phase II study showed an overall GCIG response rate of 32% (6/19) in the once every 14 days (q14 day) dose schedule and 35% (7/20) for the once every 21 days (q21 day) dose schedule. Confirmed objective response rates using RECIST were 21% (4/19) and 22% (4/18) for the q14 day and q21 day dose schedules, respectively.

CA-125 response rates were 31% (5/16) and 38% (6/16), for each dose schedule, respectively. The Phase II study has now completed enrollment with a total of 71 patients. Approximately one-third of the patients in the study remain on NKTR-102 treatment, including a number of patients in the first stage of the study, the company said.

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 (29%/10%) and neutropenia (14%/10%).

The Phase II study is evaluating two dose regimens (q14 day and q21 day) of single-agent NKTR-102 in women with platinum-resistant ovarian cancer. The study employs a two-stage design, with 41 patients in the first stage and 30 patients in the second stage.

Two patients in the q14 day dose regimen in the first stage had platinum-sensitive disease and were not evaluable for the primary outcome measure. 44% of the patients in the first stage were platinum-refractory, having progressed within three weeks of their last platinum therapy. 77% of the patients in the first stage had a platinum-free interval of less than three months (progression within three months of last platinum therapy). Secondary endpoints of the Phase II study include progression-free survival and safety.

CA-125 is a biochemical marker that is found in the blood of ovarian cancer patients and is measured to assess disease progression and recurrence. RECIST classifies response based upon tumour reduction measured by imaging methods.

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