- Nektar Therapeutics has convinced another big pharma of the promise of its second-generation cancer immunotherapy, announcing Tuesday a partnership with Pfizer to explore combination treatments in prostate and head and neck cancers.
- Through the planned collaboration, Pfizer will start a Phase 1b/2 study of Nektar's lead drug NKTR-214 together with its PD-L1 blocker Bavencio and either its PARP inhibitor Talzenna or its antiandrogen therapy Xtandi.
- Nektar has generated substantial interest in NKTR-214, which is designed to boost the number of cancer-fighting cells surrounding tumors while potentially enhancing the activity of drugs like Bavencio. That promise spurred Bristol-Myers Squibb to spend $1.85 billion to gain partial rights to the drug, but data presented to date has led to more questions than answers.
Nektar's collaboration with Pfizer suggests the pharma giant sees the same potential in NKTR-214 as Bristol-Myers Squibb did when it decided to ink its upfront-rich deal with the San Francisco-based biotech.
Investors, though, have become more skeptical on NKTR-214 ever since a confusing data presentation earlier this year at the American Society for Clinical Oncology's annual meeting disappointed.
Then, Nektar disclosed early results from a Phase 1/2 combo study of its drug paired with Bristol-Myers' Opdivo (niovlomuab), showing a lower-than-expected response rate to the pairing among patients with metastatic melanoma.
Nektar will present an update from that study this Friday at the Society for Immunotherapy in Cancer conference, but a preliminary look at the new data hasn't impressed either.
Results disclosed in an abstract Tuesday showed the overall response rate to NKTR-214 plus Opdivo has stayed at 50%, the same rate posted at ASCO. Shares in the biotech slumped by more than 10% on the news, before gaining back some of those losses.
The abstract included data on 38 patients through a cut-off of July 12, so Nektar could unveil more recent numbers when it presents the study Friday afternoon.
But investors are more wary of buying into second-generation immunotherapy approaches following the failure of Incyte's much-hyped IDO inhibitor earlier this year. Shares in a number of biotechs testing new ways of directing the immune system against cancer have fallen considerably versus their respective trading peaks.
Many of those companies, including Nektar, aim to turn "cold" tumors "hot," or immune responsive. Current generation immunotherapies, such as Pfizer and Merck KGaA's Bavencio (avelumab) and Opdivo, work well in a minority of patients but many still don't respond to treatment. Pursuit of ways to increase that response rate is the driving force behind the current wave of investment in immuno-oncology.
While Pfizer has only signed up for a clinical collaboration with Nektar, the pharma will explore two different triple combinations in metastatic castration-resistant prostate cancer and squamous cell carcinoma of the head and neck.
Both combos will pair Bavencio with NKTR-214 and add either Pfizer's recently approved Talezenna (talazoparib) or Pfizer and Astellas' prostate cancer drug Xtandi (enzalutamide).