Safety and Efficacy Evaluation of BZ371A Topically Applied on Prostatectomized Patients

Inclusion Criteria:

1. Men between the ages of 40 and 65 years;

2. Exclusive heterosexual men, regardless of race or social class.

3. RP due to prostate cancer without metastasis;

4. RP performed less than 60 days before the screening visit;

5. Erectile function prior to normal RP, defined as IIEF questionnaire with more than 22 points in domain A;

6. Stable sexual partner (more than 2 months prior to RP), and intention to maintainthe relationship during the study.

7. Continuous use of 5mg Tadalafil from the 30th up to the 60th day after RP.

Exclusion Criteria:

1. Prostate cancer in TNM stage classified as T3 or T4.

2. Perineal and/or open RP;

3. Necessity of other therapy for prostate cancer than RP, including radiation therapyor hormone therapy;

4. Uncontrolled diabetes at screening visit (HbA1C > 10%);

5. Prior spinal cord injury with lower limb paralysis;

6. Current male hormone use, or hypogonadism, defined by total testosterone below 8nmol/L (2300 pg/mL) or total testosterone between 8 and 11 nmol/L (2300 and 3170pg/mL) and free testosterone < 220 pmol/L (< 64 ng/dL);

7. Patients with current depression, characterized by use or need for use ofantidepressants.

8. Presence of genital lesions (such as severe penile fibrosis or Peyronie's disease)or active sexually transmitted disease (STD) (such as herpes, gonorrhea,candidiasis, HPV, and others) that impair analysis of local adverse effects on thegenitalia;

9. Use of topical medications in the genital region that may interfere in the IPevaluation, as well as in its absorption or drug interaction;

10. Possession of penile prosthesis;

11. History of symptomatic hypotension, or diseases that increase the risk ofsymptomatic hypotension, such as patient with heart diseases (including history ofangina and/or heart failure) and nephropathies;

12. Current use of nitrates, such as propatilnitrate (Sustrate®), isosorbide (Monocordil®, Cincordil®, Isordil®), nitroglycerin (Nitradisc®, Nitroderm TTS®, ®, Tridil®) and isosorbitol dinitrate (Isocord®);ketoconazole; ritonavir;and rifampicin.

13. Findings on ECG and/or laboratory tests that, in the Investigator's criteria, areconsidered significant and offer risk to the research volunteer's participation ormay hinder the study analyses;

14. BP outside the limits considered safe: SBP below 90 mmHg or above 170 mmHg; or DBPbelow 50 mmHg or above 100 mmHg, except situations such as "white coat syndrome";

15. Diseases that can cause priapism, such as sickle cell anemia, multiple myeloma, orleukemia;

16. Histroy of priapism, defined as painful erection from up to 6 hours.

17. Current relevant diarrhea, defined as duration over four weeks, association withabdominal pain or dysabsortive syndrome, or presence of mucus, pus, or blood in thestool;

18. Known hypersensitivity to tadalafil and/or BZ371A;

19. History of symptomatic Lactose intolorence such as: the necessity of enzymatictreatment, abdominal distension or diarrhea when ingesting products or supplementswith lactose;

20. Low adhsesion to 5mg Tadalafil use, characterized by the use of <80% of the pillsbetween the 30th and 60th day post PR;.

21. Pregnant or lacting partner.

22. Partner in childbearing age which does not accept to get exposed to the treatment

23. Any disease, condition or physical finding that the Investigator considerssignificant and that increases the risk of the research subject's participation ormay interfere with the results, including severe debilitating illness, presence ofcancer other than prostate cancer, severe mental illness persistent medicationabuse;