Inclusion Criteria:

1. Males, aged 50 years or older with prior diagnosis of BPH;
2. Patients may be eligible whether or not they are on medication for LUTS due to BPH.
3. Patients who are candidates for interventional therapy;
4. Patients who understand and have the ability to sign written informed consent prior to any study procedures and/or discontinuation of exclusionary medications;
5. Patients with an International Prostate Symptom Score of ≥ 15 points;
6. Patients with moderate to severe BPH (Bother Score ≥ 3);
7. Maximum urinary flow rate (Qmax) ≤ 15 mL/sec;
8. Post void residual volume (PVR) ≤ 300 mL;
9. Length of prostatic urethra ≥ 4.0 cm.

Exclusion Criteria:

1. Patients with any previous minimally invasive or surgical intervention for BPH.
2. Patients who are currently enrolled in or who have enrolled in another clinical trial for any disease within the past 30 days.
3. Patients with an active urinary tract infection.
4. Patients with a urethral stricture.
5. Patients with interstitial cystitis.
6. Patients with a predominant middle lobe obstruction.
7. Patients who have evidence or history of prostate or bladder cancer or carcinoma in situ of the bladder.
8. Patients with an abnormal digital rectal exam suggestive of carcinoma of the prostate.
9. Patients with an abnormal digital rectal exam suggestive of an indurated nodule.
10. Patients with a PSA of > 10 ng/ml. If the PSA is 4-10 ng/ml, local standard of care should be pursued to ensure the possibility of prostate cancer is followed up and ruled out prior to, entry into the study.
11. Patients who had a biopsy of the prostate within the past 6 weeks.
12. Patients with bleeding diathesis.
13. Patients with clinically significant renal or hepatic impairment.
14. Patients with neurological conditions felt to affect the bladder or a history of a neurogenic or chronically decompensated bladder.
15. Patients who daily use a pad or device for incontinence.
16. Patients who had an episode of unstable angina pectoris, myocardial infarction, transient ischemic attack, or cerebrovascular accident (stroke) within the past 6 months, or peripheral arterial disease with intermittent claudication or Leriches syndrome.
17. Patient has an interest in future fertility.
18. Patients with prolonged QT interval at baseline and/or who are currently taking medication that prolongs QT interval ("prolonged QT interval" defined as > 450 ms).
19. Inadequate organ function as evidenced by the following: Platelet count <100,000/mm3; WBC <4,000/mm3; Neutrophils <1,800/mm3; Hemoglobin <10 g/dL; AST and ALT >3 x ULN; Creatinine >1.5 x ULN
20. Known sensitivity to porphyrin-type drugs or known history of porphyria.
21. Inability to avoid bright indoor lighting and sunlight during the first 72 hours after LS11 administration.