Nektar looks for the positive in a failed PhIII breast cancer study

About two months ago, Nektar ($NKTR) CEO Howard Robin spent part of his day telling a reporter at the San Francisco Business Times about new blueprints for a big expansion, making way for the new staffers that would be needed to start commercializing the breast cancer drug NKTR-102. Today, the biotech may be rethinking that plan, as the drug failed in a pivotal late-stage study.

After analyzing results from 852 patients from the trial, investigators say that NKTR-102 provided a 2.1-month improvement in median overall survival compared to chemotherapies selected by participating physicians in a control arm. That was not enough to qualify for statistical significance.

Once the biotech's shares resumed trading this evening, the stock quickly slid 16%.

Not dwelling on the failure, investigators turned to a subset analysis of patients with a history of brain metastases, and found a 5.2-month advantage in median OS. Subset analyses are frequently cited as a controversial attempt at snatching victory from the jaws of defeat. But company officials were putting the most positive spin on this possible.

"In BEACON, NKTR-102 provided a clinically meaningful benefit with a greater than two month survival advantage in these late-stage breast cancer patients, many who were refractory to existing therapies," said Dr. Javier Cortes, a co-principal investigator. "NKTR-102 exhibited a lower rate of high grade adverse events including a reduced rate of neutropenia as compared to active control, which dramatically decreased the need for growth factor support in the NKTR-102 arm of the study. Of particular significance, median survival in patients with brain metastases was more than double on NKTR-102 and the 12-month survival rate for this sub-group was impressive at 44% compared to 19% with other active agents."

Analysts, however, have been concentrating on the primary endpoint, with considerable skepticism that the drug would work as Nektar hoped. JPMorgan analyst Jessica Fye recently assessed the chances of primary success at 20%.

Nektar developed 102 with its in-house polymer technology platform, billing the drug as the "first long-acting topoisomerase I-inhibitor designed to concentrate in tumor tissue, provide sustained tumor suppression throughout the entire chemotherapy cycle, and to reduce the peak exposures that are associated with toxicities of other cytotoxics."

- here's the release

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