14.1 Monotherapy
Finasteride tablets 5 mg/day was initially evaluated in patients with symptoms of BPH and enlarged prostates by digital rectal examination in two 1-year, placebo-controlled, randomized, double-blind studies and their 5-year open extensions.
Finasteride tablets was further evaluated in the finasteride tablets A Long-Term Efficacy and Safety Study, a double-blind, randomized, placebo-controlled, 4-year, multicenter study. 3,040 patients between the ages of 45 and 78, with moderate to severe symptoms of BPH and an enlarged prostate upon digital rectal examination, were randomized into the study (1,524 to finasteride, 1,516 to placebo) and 3,016 patients were evaluable for efficacy. 1,883 patients completed the 4-year study (1,000 in the finasteride group, 883 in the placebo group).
Effect on Symptom Score
Symptoms were quantified using a score similar to the American Urological Association Symptom Score, which evaluated both obstructive symptoms (impairment of size and force of stream, sensation of incomplete bladder emptying, delayed or interrupted urination) and irritative symptoms (nocturia, daytime frequency, need to strain or push the flow of urine) by rating on a 0 to 5 scale for six symptoms and a 0 to 4 scale for one symptom, for a total possible score of 34.
Patients in A Long-Term Efficacy and Safety Study had moderate to severe symptoms at baseline (mean of approximately 15 points on a 0 to 34 point scale). Patients randomized to finasteride tablets who remained on therapy for 4 years had a mean (± 1 SD) decrease in symptom score of 3.3 (± 5.8) points compared with 1.3 (± 5.6) points in the placebo group. (See Figure 1.) A statistically significant improvement in symptom score was evident at 1 year in patients treated with finasteride tablets vs placebo (-2.3 vs -1.6), and this improvement continued through Year 4.
Figure 1 Symptom Score in A Long-Term Efficacy and Safety Study
[Finasteride-Fig.1]
Results seen in earlier studies were comparable to those seen in A Long-Term Efficacy and Safety Study. Although an early improvement in urinary symptoms was seen in some patients, a therapeutic trial of at least 6 months was generally necessary to assess whether a beneficial response in symptom relief had been achieved. The improvement in BPH symptoms was seen during the first year and maintained throughout an additional 5 years of open extension studies.
Effect on Acute Urinary Retention and the Need for Surgery
In A Long-Term Efficacy and Safety Study, efficacy was also assessed by evaluating treatment failures. Treatment failure was prospectively defined as BPH-related urological events or clinical deterioration, lack of improvement and/or the need for alternative therapy. BPH-related urological events were defined as urological surgical intervention and acute urinary retention requiring catheterization. Complete event information was available for 92% of the patients. The following table (Table 5) summarizes the results.
Patients (%)*
Event Placebo
N=1503 Finasteride
N=1513 Relative
Risk† 95% CI P
Value†
Table 5: All Treatment Failures in A Long-Term Efficacy and Safety Study
All Treatment Failures
37.1
26.2
0.68
(0.57 to 0.79)
<0.001
Surgical Interventions for BPH
10.1
4.6
0.45
(0.32 to 0.63)
<0.001
Acute Urinary
Retention Requiring
Catheterization
6.6
2.8
0.43
(0.28 to 0.66)
< 0.001
Two consecutive symptom scores ≥20
9.2
6.7
Bladder Stone
0.4
0.5
Incontinence
2.1
1.7
Renal Failure
0.5
0.6
UTI
5.7
4.9
Discontinuation due to worsening of BPH, lack of improvement, or to receive other medical treatment
21.8
13.3
*patients with multiple events may be counted more than once for each type of event
†Hazard ratio based on log rank test
Compared with placebo, finasteride tablets was associated with a significantly lower risk for acute urinary retention or the need for BPH-related surgery [13.2% for placebo vs 6.6% for finasteride tablets; 51% reduction in risk, 95% CI: (34 to 63%)]. Compared with placebo, finasteride tablets was associated with a significantly lower risk for surgery [10.1% for placebo vs 4.6% for finasteride tablets; 55% reduction in risk, 95% CI: (37 to 68%)] and with a significantly lower risk of acute urinary retention [6.6% for placebo vs 2.8% for finasteride tablets; 57% reduction in risk, 95% CI: (34 to 72%)]; see Figures 2 and 3.
Figure 2 Percent of Patients Having Surgery for BPH, Including TURP
Figure 3 Percent of Patients Developing Acute Urinary Retention (Spontaneous and Precipitated)
[Finasteride-fig.3]
Effect on Maximum Urinary Flow Rate
In the patients in A Long-Term Efficacy and Safety Study who remained on therapy for the duration of the study and had evaluable urinary flow data, finasteride tablets increased maximum urinary flow rate by 1.9 mL/sec compared with 0.2 mL/sec in the placebo group.
There was a clear difference between treatment groups in maximum urinary flow rate in favor of finasteride tablets by month 4 (1.0 vs 0.3 mL/sec) which was maintained throughout the study. In the earlier 1-year studies, increase in maximum urinary flow rate was comparable to A Long-Term Efficacy and Safety Study and was maintained through the first year and throughout an additional 5 years of open extension studies.
Effect on Prostate Volume
In A Long-Term Efficacy and Safety Study, prostate volume was assessed yearly by magnetic resonance imaging (MRI) in a subset of patients. In patients treated with finasteride tablets who remained on therapy, prostate volume was reduced compared with both baseline and placebo throughout the 4-year study. Finasteride tablets decreased prostate volume by 17.9% (from 55.9 cc at baseline to 45.8 cc at 4 years) compared with an increase of 14.1% (from 51.3 cc to 58.5 cc) in the placebo group (p<0.001). (See Figure 4.)
Results seen in earlier studies were comparable to those seen in A Long-Term Efficacy and Safety Study. Mean prostate volume at baseline ranged between 40 to 50 cc. The reduction in prostate volume was seen during the first year and maintained throughout an additional five years of open extension studies.
Figure 4 Prostate Volume in A Long-Term Efficacy and Safety Study
[finasteride-fig4a]
Prostate Volume as a Predictor of Therapeutic Response
A meta-analysis combining 1-year data from seven double-blind, placebo-controlled studies of similar design, including 4,491 patients with symptomatic BPH, demonstrated that, in patients treated with finasteride tablets, the magnitude of symptom response and degree of improvement in maximum urinary flow rate were greater in patients with an enlarged prostate at baseline.
14.2 Combination with Alpha-Blocker Therapy
The Medical Therapy of Prostatic Symptoms (MTOPS) Trial was a double-blind, randomized, placebo-controlled, multicenter, 4- to 6-year study (average 5 years) in 3,047 men with symptomatic BPH, who were randomized to receive finasteride tablets 5 mg/day (n=768), doxazosin 4 or 8 mg/day (n=756), the combination of finasteride tablets 5 mg/day and doxazosin 4 or 8 mg/day (n=786), or placebo (n=737).
All participants underwent weekly titration of doxazosin (or its placebo) from 1 to 2 to 4 to 8 mg/day. Only those who tolerated the 4 or 8 mg dose level were kept on doxazosin (or its placebo) in the study. The participant's final tolerated dose (either 4 mg or 8 mg) was administered beginning at end-Week 4. The final doxazosin dose was administered once per day, at bedtime.
The mean patient age at randomization was 62.6 years (±7.3 years). Patients were Caucasian (82%), African American (9%), Hispanic (7%), Asian (1%) or Native American (<1%). The mean duration of BPH symptoms was 4.7 years (±4.6 years). Patients had moderate to severe BPH symptoms at baseline with a mean AUA symptom score of approximately 17 out of 35 points. Mean maximum urinary flow rate was 10.5 mL/sec (±2.6 mL/sec). The mean prostate volume as measured by transrectal ultrasound was 36.3 mL (±20.1 mL).
Prostate volume was ≤20 mL in 16% of patients, ≥50 mL in 18% of patients and between 21 and 49 mL in 66% of patients.
The primary endpoint was a composite measure of the first occurrence of any of the following five outcomes: a ≥4 point confirmed increase from baseline in symptom score, acute urinary retention, BPH-related renal insufficiency (creatinine rise), recurrent urinary tract infections or urosepsis, or incontinence. Compared to placebo, treatment with finasteride tablets, doxazosin, or combination therapy resulted in a reduction in the risk of experiencing one of these five outcome events by 34% (p=0.002), 39% (p<0.001), and 67% (p<0.001), respectively. Combination therapy resulted in a significant reduction in the risk of the primary endpoint compared to treatment with finasteride tablets alone (49%; p≤0.001) or doxazosin alone (46%; p≤0.001). (See Table 6.)
Table 6: Count and Percent Incidence of Primary Outcome Events by Treatment Group in MTOPS
Treatment Group
Placebo
N=737
Doxazosin
N=756
Finasteride
N=768
Combination
N=786
Total
N=3,047
Event
N (%)
N (%)
N (%)
N (%)
N (%)
AUA 4-point rise 100 (13.6)
59 (7.8)
74 (9.6)
41 (5.2)
274 (9.0)
Acute urinary
retention 18 (2.4) 13 (1.7)
6 (0.8)
4 (0.5)
41 (1.3)
Incontinence 8 (1.1)
11 (1.5)
9 (1.2)
3 (0.4)
31 (1.0)
Recurrent UTI/urosepsis 2 (0.3)
2 (0.3)
0 (0.0)
1 (0.1)
5 (0.2)
Creatinine rise 0 (0.0)
0 (0.0)
0 (0.0)
0 (0.0)
0 (0.0)
Total Events 128 (17.4)
85 (11.2)
89 (11.6)
49 (6.2)
351 (11.5)
The majority of the events (274 out of 351; 78%) was a confirmed ≥4 point increase in symptom score, referred to as symptom score progression. The risk of symptom score progression was reduced by 30% (p=0.016), 46% (p<0.001), and 64% (p<0.001) in patients treated with finasteride tablets, doxazosin, or the combination, respectively, compared to patients treated with placebo (see Figure 5). Combination therapy significantly reduced the risk of symptom score progression compared to the effect of finasteride tablets alone (p<0.001) and compared to doxazosin alone (p=0.037).
Figure 5
Cumulative Incidence of a 4-Point Rise in AUA Symptom Score by Treatment Group
[Finasteride-Fig.5]
Treatment with finasteride tablets, doxazosin or the combination of finasteride tablets with doxazosin, reduced the mean symptom score from baseline at year 4. Table 7 provides the mean change from baseline for AUA symptom score by treatment group for patients who remained on therapy for four years.
Table 7: Change From Baseline in AUA Symptom Score by Treatment Group at Year 4 in MTOPS
Placebo
N=534 Doxazosin
N=582 Finasteride
N=565 Combination
N=598
Baseline Mean (SD)
16.8 (6.0)
17.0 (5.9)
17.1 (6.0)
16.8 (5.8)
Mean Change
AUA Symptom Score (SD)
- 4.9 (5.8)
- 6.6 (6.1)
- 5.6 (5.9)
-7.4 (6.3)
Comparison to
Placebo (95% CI)
- 1.8
(-2.5, -1.1)
- 0.7
(-1.4, 0.0)
-2.5
(-3.2, -1.8)
Comparison to
Doxazosin alone (95% CI)
-0.7
(-1.4, 0.0)
Comparison to
Finasteride alone (95% CI)
-1.8
(-2.5, -1.1)
The results of MTOPS are consistent with the findings of the 4-year, placebo-controlled study A Long-Term Efficacy and Safety Study [see CLINICAL STUDIES (14.1)] in that treatment with finasteride tablets reduces the risk of acute urinary retention and the need for BPH-related surgery. In MTOPS, the risk of developing acute urinary retention was reduced by 67% in patients treated with finasteride tablets compared to patients
treated with placebo (0.8% for finasteride tablets and 2.4% for placebo). Also, the risk of requiring BPH-related invasive therapy was reduced by 64% in patients treated with finasteride tablets compared to patients treated with placebo (2.0% for finasteride tablets and 5.4% for placebo).
14.3 Summary of Clinical Studies
The data from these studies, showing improvement in BPH-related symptoms, reduction in treatment failure (BPH-related urological events), increased maximum urinary flow rates, and decreasing prostate volume, suggest that finasteride tablets arrests the disease process of BPH in men with an enlarged prostate.