• Willing and able to give electronically informed consent for participation in the trial and willing and able to participate in all procedures and follow-up evaluations necessary to complete the trial.

• Male or female patient clinically diagnosed with KOA, no later than 3 months prior to Visit 1. The KOA diagnosis should be confirmed in the patient's medical record.

• Dominant pain in one knee due to KOA with weight bearing pain between 4 and 8 inclusive on the NRS scale (0-10) at the time of inclusion (checked at screening \[Visit 1\] and confirmed at Visit 2, pain during the last 7 days).

• Age 40 to 79 years, inclusive at the time of Visit 1.

• Body mass index (BMI) ≥ 18.5 and \< 35.0 kg/m2.

• Patients without abnormal clinically significant medical history, physical findings, vital signs, hypotension, cardiovascular disease, ECG, and laboratory values at the time of the screening visit, as judged by the Investigator. (Discussion is encouraged between the Investigator and the Medical Monitor regarding the clinical relevance of any abnormal laboratory value during the pre-dose period.)

• Patient is willing to discontinue all pain medication (COX-2 inhibitors, NSAIDs, and opioid analgesics) at least 10 days before trial drug administration (prior to Day 1) and for the trial duration. Paracetamol will be allowed as rescue medication up to max 4000 mg/day (except for 24 hours prior to visit to the trial site).

• Patient agrees not to take additional knee symptom-modifying drugs (e.g., glucosamine, collagen, HA) at least 10 days before trial drug administration (prior to Day 1) and for the trial duration.

• WOCBP must practice abstinence heterosexual intercourse (only allowed when this is the preferred and usual lifestyle of the patient) or agree to use a highly effective method of contraception with a failure rate of \< 1 % to prevent pregnancy from that least 2 weeks prior to the administration of IMP to 4 weeks after the last administration of IMP. In addition, any male partner of a female patient must, unless he has undergone vasectomy, agree to use a condom from the first administration of IMP until 4 weeks after the last administration of IMP.

• The following are considered highly effective methods of contraception:

⁃ combined (estrogen and progestogen containing) hormonal contraception associated with inhibition of ovulation (oral, intravaginal, transdermal),

⁃ progestogen-only hormonal contraception associated with inhibition of ovulation (oral, injectable, implantable),

⁃ intrauterine device \[IUD\]or intrauterine hormone-releasing system \[IUS\]). WOCBP must refrain from donating eggs from the first IMP administration until 3 months after the last IMP administration.

• Women of non-childbearing potential are pre-menopausal females who have undergone any of the following surgical procedures; hysterectomy, bilateral salpingectomy, or bilateral oophorectomy, or who are post-menopausal defined as 12 months of amenorrhea (in questionable cases a blood sample with detection of follicle stimulating hormone \[FSH\] \>25 IU/L is confirmatory).

• Male patients must be willing to use condom or be vasectomized or practice sexual abstinence from heterosexual intercourse (only allowed when this is the preferred and usual lifestyle of the patient) to prevent pregnancy and drug exposure of a partner and refrain from donating sperm from the first administration of IMP until 3 months after the last administration of IMP. Any female partner of a non-vasectomized male patient who is of childbearing potential must use contraceptive methods with a failure rate of \< 1% to prevent pregnancy (see above) from at least 2 weeks prior to the first administration of IMP to 4 weeks after the last administration of IMP.

⁃ Patients without contraindications for treatment with diclofenac.