A Phase 2, Randomised, Double-Blind, Placebo-Controlled Trial to Investigate the Safety and Efficacy of AV608 in Subjects with Idiopathic Detrusor Overactivity

1) Female, 18 to 65 years of age, inclusive. Individuals outside this age range will not be included in line with standard clinical trial practice.
2)A current primary diagnosis of OAB consistent with idiopathic detrusor overactivity with symptoms present for at least 6 months prior to Screening.
3)Idiopathic detrusor overactivity, demonstrated by a urodynamic observation, which is characterized by involuntary detrusor contraction during the filling phase and is associated with a sensation of urgency.
4)Evidence of frequency (greater than 8 micturitions/24 hours) in combination with urinary urgency during the 7 days prior to baseline (Visit 2) based on the micturition diary.
5)Willingness to participate in this study as evidenced by a signed, written informed consent form (ICF).
6)If of child*bearing potential (i.e., not post*menopausal or documented to be surgically sterile) willingness to avoid pregnancy and practice adequate birth control (e.g., oral contraception, intrauterine devices, implantable devices, depot contraceptives, double barrier method) from the time of study enrollment through at least 30 days after the final dose of study medication.
7)Negative serum pregnancy test at Visit 1 (Screening) and negative urine pregnancy test at Visit 2 (Randomisation).
8)Agrees to refrain from blood donation during the course of the study.

1) Subjects who are pregnant or lactating.
2) Clinically significant abnormality or clinically significant unstable medical condition as indicated by medical history, physical examination, ECG results, clinical laboratory testing, or the investigator's judgment at Screening (Visit 1) or Baseline (Visit 2).
3) QTc interval of 470 msec or greater at Screening (Visit 1).
4) Predominant stress urinary incontinence versus urge urinary incontinence based on subject history.
5) Neurogenic bladder (e.g. associated with spinal cord injury, multiple sclerosis, etc.).
6) Post micturition volume of >100 mL at baseline assessment.
7) Maximum bladder capacity > 400 mL at baseline assessment.
8) Anatomic or structural abnormalities possibly causing urinary incontinence or urgency,including but not limited to urogenital prolapse stage 2 or more according to the Pelvic Organ Prolapse Quantification (POP*Q) system.
9) Current UTI or frequent UTIs (i.e., greater than 4 UTIs per year), interstitial cystitis, hematuria of unknown cause, or use of indwelling catheter.
10) Urological or gynecological surgery within 3 months of the baseline urodynamic assessment; cystoscopy within 30 days of the baseline urodynamic assessment.
11) Electro*stimulation therapy, bladder training, or physiotherapy for bladder control within 2 weeks of Screening (Visit 1).
12) History (within 1 year of Screening) of alcohol or substance dependence (except nicotine dependence) according to DSM*IV*TR criteria.
13) History of any kind of cancer within the last 2 years.
14) Existing non*malignant tumors that could compromise the function and/or anatomy of the lower urinary tract.
15) Subjects who have taken any prohibited medications within two weeks of baseline (Visit 2) or have any anticipated need or intended use of these medications during the study. Prohibited medications include, but are not limited to, oxybutynin, tolterodine, duloxetine, trospium chloride, darifenacin, solfenacin, and herbal preparations.
16) Participation in any clinical trial within the past 3 months (for investigational drugs, products, or devices).
17) Subjects who have previously received AV608 (previously known as NKP*608).
18) Positive result on urine testing for drugs of abuse (cannabis, amphetamines, cocaine, and phenycylidine) at Screening (Visit 1).
19) Any past or present history of liver disease (with the exception of history of hepatitis A) or renal failure (creatinine clearance < 60 cc/minute).
20) Current hypothyroidism or hyperthyroidism or laboratory findings consistent with thyroid dysfunction. Subjects who are being treated for thyroid disorder are eligible if they have been on stable doses of thyroid hormone for at least 6 months prior to Screening (Visit 1) and are currently euthyroid.
21) Any other condition that, in the opinion of the investigator, would jeopardise the safety or rights of a subject participating in the trial or would render the subject unable to comply with the protocol.
22) Members of the investigative staff or their families.