New Medicines

Moderate-to-severe chronic back pain


New molecular entity

Development and Regulatory status

Mar 20Removed from company pipeline [14].
Jan 20Nektar has withdrawn the new drug application following an advisory committee unanimous vote against approval. Nektar has stopped further development of the drug [13].
Nov 19Nektar continue to work closely with the FDA, and anticipate an advisory committee meeting for NKTR-181 will be formally scheduled to occur within the next several months. If approved, they plan to commercialise NKTR-181 through a wholly owned subsidiary, Inheris Biopharma, Inc., with one or more potential capital partners to support commercial launch. No plans for EU development or colllaborations have been reported [12].
Jul 19The FDA has postponed an Advisory Committee meeting whilst it addresses scientific and policy issues. This may result in a delay launching the drug past the expected early 2020 planned date [11].
Jun 19Plans for EU development are unclear. Nektar describes oxycodegol (NKTR-181) as unpartnered. Neither Nektar or Inheris have premises in the EU [9].
May 19According to its quarterly report, Nektar plan to commercialise NKTR-181 through Inheris with one or more potential capital partners to support commercial launch. Since they have not yet completed work to establish a commercial launch capability for NKTR-181, there remains substantial risk and uncertainties related to successful and timely completion of establishing this commercialisation infrastructure for NKTR-181. Nektar has no experience commercialising products, previously relying on collaborations with other companies. Nektar does not specify its plans for launch in countries other than the US [10].
May 19Inheris has taken over launch plans for Nektar´s drug. FDA decision is expected on 29 August 2019 [8].
May 19Nektar Therapeutics have announced the launch of a new subsidiary, Inheris Biopharma, Inc., which will be responsible for the launch and commercialisation of loxicodegol.[7]
May 18Filed in US for chronic low back Pain in adults new to opioid therapy [6].
Apr 18Nektar Therapeutics announces its intention to submit a NDA to US FDA in May 18 [5].
Mar 17Nektar have previously stated that if the SUMMIT-07 PIII trial results were positive, they would out-license NKTR-181 to a company with an existing strong presence in the pain market [4].
Jun 12Granted Fast Track designation by the US FDA for treatment of moderate-to-severe chronic pain [1].


First-in-class, PEGylated mu-opioid agonist. Taken twice daily. It is being developed as a safer opioid, with a reduced potential for abuse, through the use of advanced polymer conjugation technology platform.
Back pain is extremely common. 60-80% of people in the UK report back pain at some time in their lives. A UK population-based cross-sectional study of people aged 25 years and older found the one-month period prevalence of low back pain to be around 30%, peaking at age 41-50 years. The one-year prevalence of chronic low back pain is about 1% [2].
Moderate-to-severe chronic back pain

Trial or other data

Mar 17A PIII trial of NKTR-181 meets its primary endpoint with statistically significant improvement in pain scores over placebo. Nektar enrolled opioid-naive patients with moderate to severe chronic low back pain in the trial. All the subjects were titrated up to a tolerable, effective dose of NKTR-181—up to 400 mg twice a day—before being randomized to either continue on the experimental drug or switch to placebo. This marked the start of the 12-week double-blind randomized treatment period. The primary endpoint looked at changes in pain scores over this period. During the titration period, pain scores fell from 6.73 to 2.32, a 65% decline. Then, once subjects were randomized, the pain scores of the treatment and placebo cohorts rose respectively by 0.92 and 1.46. That difference was enough for the trial to hit its primary endpoint with a p-value of 0.0019. The difference was more pronounced among the 83% of patients who completed the trial. In this subgroup, the placebo and treatment pain scores rose by 1.25 and 0.56, respectively. Nektar also reported the performance of NKTR-181 against some secondary endpoints. The trial found statistically significant differences in the proportion of patients in the treatment and placebo groups who achieved 30% and 50% reductions in pain. In the NKTR-181 arm, 71.2% of patients hit the 30% mark and 51.1% of subjects achieved a decline of 50% or more. Safety data show 10.4% of patients in the treatment arm experienced nausea and 8.7% suffered from constipation. Neither adverse event affected more than 5% of patients in the placebo group. The data come from the double-blind randomized treatment period. Nektar is yet to post safety data on the titration period [3].
Mar 15The PIII SUMMIT-LTS trial to evaluate the long-term safety and tolerability of NKTR 181 in patients with moderate to severe chronic lower back pain or chronic non-cancer pain starts (NCT02367820). This 52-week, open-label study intends to enrol approximately 600 patients in the US [1].
Feb 15Nektar Therapeutics initiates a 12-week PIII trial to evaluate the safety, efficacy and tolerability of NKTR 181 in opioid-naive patients with moderate to severe chronic low back pain (SUMMIT-07; NCT02362672). The randomised trial will evaluate the change in pain as measured by change in patient´s weekly pain score from baseline as the primary endpoint of the trial. Enrolment of approximately 416 participants who have failed previous treatment with non-opioid therapeutics, was completed in August 2016, in the US [1].