PSD502 in Subjects With Premature Ejaculation

Inclusion Criteria: * Willing and able to provide written informed consent. * Male and aged 18 years and over. * Diagnosed with PE according to the ISSM definition, that is, he ejaculates always or nearly always prior to or within about one minute of vaginal penetration; and is unable to delay ejaculation on all or nearly all vaginal penetrations; and experiences negative personal consequences, such as distress, bother, frustration and/or the avoidance of sexual intimacy. * Subject has lifelong PE from the first sexual experience. * Subject must be in a stable heterosexual and monogamous relationship of at least 3 months' duration with this partner. * Subject has at least documented 3 sexual encounters, each separated by an interval of at least 24 hours, in the baseline period. * IELT ≤1 minute in all sexual encounters in the baseline period. * The subject's partner must provide written informed consent, be aged 18 years or over and willing to comply with the study procedures. * Subject indicates a level of Bother on Item 3 of the PEBEQ of either "moderately", "quite a bit" or "extremely" on all encounters during the baseline period. * Subject registers a level of "bother" at a score of 4 or greater on an 11-point NRS scale at Screening to ensure that subjects not bothered by the quickness of their ejaculation are not entered into the baseline period. Exclusion Criteria: * Subject, or his sexual partner, has received an investigational (unapproved) drug within 30 days of Screening. * Subject has erectile dysfunction, defined as an IIEF-5 score of 21, unless the low score is entirely related to PE symptoms in the opinion of the Investigator. * The subject, or his sexual partner, has a physical or psychological condition that would prevent them from undertaking the study procedures, including, but not limited to, the following: 1. Urological disease (e.g., prostatitis, urinary tract infection) or genitourinary surgery within 8 weeks of Screening. 2. Ongoing significant psychiatric disorder (e.g., bipolar disease, depression / anxiety disorder or schizophrenia) not controlled by medication. * Subject has safety testing abnormalities at the Screening Visit, in particular liver function tests or anemia, that are indicative of a medical condition that would preclude further participation in the opinion of the Investigator. * Subjects taking tricyclic antidepressants, monoamine oxidase inhibitors (MAOIs) or selective serotonin reuptake inhibitors (SSRIs), for indications other than PE, where the dose has been changed within 4 weeks of Screening or it is planned that the dose will change during the treatment period. * Subject has received any treatment for PE e.g., anti-depressant therapy, local anesthetic spray, eutectic mixture of local anesthetics (EMLA®) cream, intra-cavernosal injection, tramadol or psychotherapy within 4 weeks of Screening * Subject, or his sexual partner, has a current history of alcohol or drug abuse, in the opinion of the Investigator. * The subject, or his sexual partner, is unlikely to understand or be able to comply with study procedures, for whatever reasons. * Subject, or his sexual partner, has known drug sensitivity to amide-type local anesthetics. * Subjects with pregnant partners. * Subject with sexual partners of child-bearing potential and not using appropriate contraception (hormonal contraception or intra-uterine device \[IUD\]). * Subject, or his sexual partner, has a history of glucose-6-phosphate dehydrogenase (G 6 PD) deficiency or currently using medications that would increase susceptibility to methemoglobinemia (e.g., anti-malarial agents) or has congenital or acquired methemoglobinemia, or is at risk of industrial exposure to agents causing methemoglobinemia. * Subject, or his sexual partner, uses Class I (e.g., mexiletine, tocainide) or III (e.g., amiodarone, sotalol) anti-arrhythmic drugs, or cimetidine, beta blockers or local anesthetics. * Subject has received PSD502 in a clinical study or has received Fortacin within 1 year of Screening.