Nektar has had a mixed few months as data fed through for its lead cancer drug NKTR-214, but new data in bladder cancer should help steady the ship, although a drop in ORR has hit the biotech's shares.
The biotech is due to report updated results from its PIVOT-02 trial of NKTR-214 in combination with partner Bristol-Myers Squibb’s Opdivo at the ASCO Genitourinary Cancers Symposium later this week. According to the abstract, the combination achieved an overall objective response rate (ORR) of 48%, including 17% complete responses, in patients with metastatic urothelial carcinoma (mUC), the most common form of bladder cancer.
That ORR is lower than the 60% reported with NKTR-214 at ASCO’s main 2018 meeting, but analyst Robert Hazlett of BTIG is remaining positive, saying the results are still “well above what is likely to be necessary for meaningful response and licensure in UC patients,” according to a StreetInsider.com report. Still, a drop is not what investors wanted to see, and shares were off 9% in mid-morning trading.
Nektar and BMS were forced to defend the combination regimen at last year’s ASCO meeting when data from the PIVOT-02 trial in melanoma seemed to reveal a dip in response rates compared to an earlier readout. Later in 2018, at the SITC meeting, additional results from the melanoma cohort seemed to suggest the ORR was holding steady.
Breaking down the trial into separate solid tumor cohorts means that the number of patients being assessed is pretty small—for example there are just 23 evaluable subjects in the latest mUC readout—and that means some variation in response at these interim stages is not unexpected.
NKT2-214 is a CD122-biased agonist designed to stimulate the patient’s immune system via the IL-2 pathway, and its importance to Nektar is hard to overstate. Last year, BMS committed $3.6 billion to develop NKTR-214 in combination with Opdivo and Yervoy, including $1 billion upfront and an $850 million purchase of Nektar stock.
BMS’ decision to merge with Celgene sparked concerns that the Nektar collaboration could drop in priority, but the news last month that NKTR-214 and Opdivo would start two new phase 3 studies in front-line and second-/third-line non–small-cell lung cancer (NSCLC) laid those fears to rest.
At the time, analyst Andy Hsieh at William Blair said: “we continue to believe in the disruptive potential of NKTR-214 as the compound progresses to pivotal studies across various tumor types.” At last count, BMS and Nektar were planning 20 trials across nine cancer indications.
Checkpoint inhibitors such as Opdivo have already transformed the treatment of mUC when given on their own, but a sizable proportion of patients don’t respond to them and there is still a pressing need for new treatment options, particularly for the first-line treatment of people who can’t be given cisplatin and whose tumors are PD-L1-negative. Encouragingly, the NKTR-214/Opdivo combo also seemed to work in PD-L1 positive and negative tumors.
Nektar is planning to hold a conference call on Friday to discuss the data following the presentation at the ASCO symposium.