1:13 PM
 | 
Nov 06, 2018
 |  BC Extra  |  Clinical News

Nektar shares fall on updated response data for NKTR-214 combo

Nektar Therapeutics (NASDAQ:NKTR) was off $3.92 (10%) to $36.08 on Tuesday as investors digested updated response data released in an abstract ahead of this week's SITC meeting from a Phase I/II trial of NKTR-214 plus anti-PD-1 mAb Opdivo nivolumab.

The update appeared to disappoint investors who had hoped to see the response rate rise in a larger cohort of patients and with longer follow-up. However, the updated data, which showed no change from a 50% objective response rate (ORR) among patients with melanoma reported at the American Society of Clinical Oncology meeting in June, only included about six weeks of additional follow-up.

Data to be released Friday should be more telling. Nektar spokesperson Jennifer Ruddock told BioCentury the company's oral presentation will include updated data with three additional months of maturity for the 38 patients on treatment, as well as more details on the complete response rate and disease control rate (DCR). The Society for Immunotherapy of Cancer meeting runs Nov. 7-11 in Washington.

The readout from the SITC abstract showed investigator-assessed responses in 19 of 38 evaluable previously untreated patients with metastatic stage IV melanoma in the Phase I/II PIVOT-02 trial, as of a July 12 cut-off. At ASCO, Nektar reported an ORR of 50% among 28 melanoma patients, as of a May 29 cut-off (see "Nektar Plummets on Lower-Than-Expected Response Rates").

NKTR-214 is an immunostimulatory cytokine engineered to selectively activate IL-2 receptor β chain (CD122; IL2RB) receptors on cytotoxic T cells, resulting in increased PD-1 expression on T cells and NK cells in the tumor microenvironment.

Bristol-Myers Squibb Co. (NYSE:BMY) markets Opdivo. The pharma and Nektar are co-developing the NKTR-214 combo under a February deal in which Nektar received $1.85 billion in upfront cash and equity (see "Clever Pegylation Pay Off").

The partners plan to start a Phase III trial this year to evaluate NKTR-214 plus Opdivo vs. Opdivo alone in treatment-naïve advanced melanoma patients.

In the Phase III CheckMate -067 trial in 945 previously untreated patients with unresectable stage III/IV melanoma, Opdivo plus BMS's anti-CTLA-4 mAb Yervoy ipilimumab led to a best ORR as assessed by the investigator of 57.7%. The combo led to a confirmed ORR of 50%.

Separately on Tuesday, Nektar partnered with Pfizer Inc. (NYSE:PFE) to combine NKTR-214 with several of the pharma's marketed drugs to treat prostate cancer, testing the biotech's hypothesis that stimulation of IL-2 alongside these other MOAs in tumors with a high mutational burden could provide synergistic benefits (see "Pfizer's PARP, Androgen Inhibitors Next Combo Partners for NKTR-214").

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