Superiority of Dutasteride Over Finasteride in Hair Regrowth and Reversal of Miniaturization in Men with Androgenetic Alopecia: A Randomized Controlled Open-label, Evaluator-blinded Study

Design

Prospective, parallel, randomized, open-label superiority study

N= 72

Objective

To compare the efficacy, safety, and tolerability of dutasteride and finasteride in men with androgenetic alopecia (AGA)

Study Groups

Dutasteride (n= 35)

Finasteride (n= 37)

Inclusion Criteria

Aged 18 to 40 years with AGA classified as Grade III vertex, IV, or V (excluding types IV and V anterior)

Exclusion Criteria

Patients using minoxidil, anti-androgenic drugs causing hypertrichosis (phenytoin, acetazolamide, cyclosporine, diazoxide, psoralens, penicillamine, streptomycin and cortisone); or hypotrichosis within ≤ 6 months; systemic illness; smokers or tobacco chewers; history of breast or prostate cancer; first degree relative with prostate cancer before the age of 50

Methods

Patients were randomly assigned to receive either 0.5 mg dutasteride or 1 mg finasteride daily for a period of 24 weeks. Clinical assessment was performed by blinded and unblinded dermatologists using standardized photographs of the vertex scalp taken by placing the head on a stereotactic positioning device.

Duration

Enrollment: January 2013 to May 2014

Intervention: 24 weeks

Follow-up: N/A

Outcome Measures

Primary: Hair counts (thick and thin) in the target area from modified phototrichograms; global photography evaluation

Secondary: Subjective assessment using a preset questionnaire

Baseline Characteristics

Dutasteride

(n= 35)

Finasteride

(n= 37)

Age, years (mean)

Total hair count

Thin hair count

Thick hair count

Results

Endpoint

Dutasteride (n=35)

Finasteride (n=37)

p-Value

Change in hair counts in target area

Total hair count

Thin hair count

Thick hair count

23.14 ± 8.44

7.37 ± 11.99

30.51 ± 12.86

4.30 ± 12.46

1.27 ± 15.03

5.57 ± 12.97

<0.001

0.0156

<0.001

Global photography evaluation (change from baseline) 

Hair loss from top of scalp (decreased, same, increased)

Bitemporal recession (decreased, same, increased)

33, 2, 0

5, 30, 0

27, 9, 1

0, 37, 0

0.035

0.023

Subjective assessment using a preset questionnaire

0

1

2

3

4

5.7%

2.9%

17.1%

51.4%

22.9%

5.4%

24.3%

37.8%

29.7%

2.7%

Adverse Events

Study Author Conclusions

In our study, dutasteride 0.5 mg was found to be significantly more effective than finasteride 1 mg in men aged 18–40 years with androgenetic alopecia as assessed by hair counts, subject self-assessment and blinded and non-blinded evaluation of global photographs.

InpharmD Researcher Critique

The study included a short duration, small sample size, and open-label design, which may affect the generalizability and robustness of the results. Notably, the observed variation in finasteride's effectiveness might be influenced by genetic polymorphisms, highlighting the need for personalized approaches in treatment.

Long-Term Effectiveness and Safety of Dutasteride versus Finasteride in Patients with Male Androgenic Alopecia in South Korea: A Multicentre Chart Review Study

Design

Retrospective, observational, multi-center chart review

N= 600

Objective

To describe baseline characteristics, treatment patterns, and long-term safety and effectiveness of dutasteride versus finasteride

Study Groups

Dutasteride (n= 295)

Finasteride (n= 305)

Inclusion Criteria

Aged ≥ 18 years; male patients with confirmed androgenic alopecia (AGA) with ≥ 1 prescription for either treatment; ≥ 3 years of available medical charts during the observation period while receiving the treatment prescribed on the index date

Exclusion Criteria

Received any prescription of dutasteride ≤ 12 weeks before finasteride initiation or any prescription of finasteride ≤ 8 weeks before dutasteride initiation; prior surgical correction of scalp hair loss; history of malignancy other than non-melanotic cancers; systemic cytotoxic therapy; diagnosis of global hair thinning; scarring of the scalp; hair loss not caused by AGA; any other condition of the scalp or hair

Methods

A pilot study with 50 patients assessed the quality of data needed to populate the case report form for the full study. The index date was defined as the first prescription of dutasteride or finasteride for patients with confirmed AGA and data was collected retrospectively from medical charts and entered into an electronic CRF by clinical staff.

Patients were retrospectively assessed for the safety and efficacy of either dutasteride (0.5 mg/day) or finasteride (1 mg/day) using the basic and specific (BASP) classification of AGA. Effectiveness and safety data were extracted from patient charts at the index date and at each patient visit during the observation period.

Duration

Enrollment: January 2010 to December 2019

Intervention: Index date until death, loss to follow-up, or data cut off

Follow-up: Three years post-index

Outcome Measures

BASP classifications of AGA; adverse events (common and serious)

Baseline Characteristics

Dutasteride (n= 295)

Finasteride (n= 305)

Age, years

Smoking status

Never (<100 cigarettes during lifetime)

Former

Current

n= 91

43 (47.3%)

18 (19.8%)

30 (33.0%)

n= 32

14 (43.8%)

5 (15.6%)

13 (40.6%)

Alcohol consumption

No alcohol consumption

Light to moderate (≤14 drinks/wk)

Heavy (>14 drinks/wk)

n= 8

1 (12.5%)

2 (25.0%)

5 (62.5%)

n= 5

1 (20%)

3 (60%)

1 (20%)

Family history of AGA

Yes

No

n= 213

163 (76.5%)

50 (23.5%)

n= 140

108 (77.1%)

32 (22.9%)

Recent hair loss

Yes

No

n= 255

86 (33.7%)

169 (66.3%)

n= 195

103 (52.8%)

92 (47.2%)

Age at which hair loss was first observed, years

Baseline BASP classification

BASP severity^†

Mild (M1-2, C1, V1-2, F1-3)

Moderate (M3, C2, V3)

Severe (C3, U1-3)

75 (74.3%)

24 (23.8%)

2 (2.0%)

85 (90.4%)

9 (9.6%)

0 

BASP basic type

L

M

M0

M1

M2

M3

C

U

0

93 (92.1%)

17 (16.8%)

29 (28.7%)

33 (32.7%)

14 (13.9%)

7 (6.9%)

1 (1.0%)

4 (4.3%)

87 (92.6%)

11 (11.7%)

33 (35.1%)

40 (42.6%)

3 (3.2%)

3 (3.2%)

0

BASP specific type

V

F

80 (79.2%)

81 (80.2%)

48 (51.1%)

46 (48.9%)

Use of treatments related to AGA

Any

Topical minoxidil

263 (89.2%)

210 (79.8%)

207 (78.7%)

222 (72.8%)

131 (59.0%)

129 (58.1%)

^† Severity was determined by the more severe of basic type or specific type. For example, if a patient had M1 (mild) as the basic type and V3 (moderate) as the specific type, they would be classified as moderate.

For patients with available BASP measurements at index, most exhibited basic M type hair loss. Comorbidities were significantly higher among dutasteride-treated patients versus dinasteride, and more dutasteride patients were receiving a form of AGA treatment at baseline.

Results

BASP classifications of AGA*

Dutasteride (n= 295)

Finasteride (n= 305)

IRR (95% CI; p-value)

BASP basic type

Patients with improvement in BASP basic type

IR of improvement in BASP basic type, 100 PPPY

51

44 (86.3%)

79.09

57

26 (45.6%)

23.27

Basic M type

Patients with improvement in basic M type

IR of improvement in basic M type, 100 PPPY

50

43 (86%)

80.40

55

25 (45.5%)

23.21

BASP specific V type

Patients with improvement in V type

IR of improvement in V type, 100 PPPY

55

49 (89.1%)

89.70

33

21 (63.6%)

37.38

BASP specific F type

Patients with improvement in F type

IR of improvement in F type

56

48 (85.7%)

75.80

36

19 (52.8%)

29.88

Adverse events

Dutasteride (n= 250)

Finasteride (n= 285)

Any adverse event

19 (7.6%)

30 (10.5%)

Any adverse event of special interest

Sexual adverse events

Decreased libido

Impotence/erectile dysfunction

4 (1.6%)

4 (1.6%)

3 (1.2%)

1 (0.4%)

3 (1.1%)

3 (1.1%)

2 (0.7%)

0

Yes

Yes

Yes

Yes

Any other adverse event

Allergic reactions/face/rash/urticaria

Back pain

Diarrhea

Dyspepsia

Fatigue

Other

Skin disorders

17 (6.8%)

1 (0.4%)

1 (0.4%)

1 (0.4%)

1 (0.4%)

1 (0.4%)

12 (4.8%)

11 (4.4%)

27 (9.5%)

2 (0.7%)

0

2 (0.7%)

1 (0.4%)

0

24 (8.4%)

17 (6.0%)

No

Yes

Yes

Yes

Yes

Yes

No

Yes

Any SAE

Serious cardiovascular event

Other SAE

0

0

0

2 (0.7%)

1 (0.4%)

1 (0.4%)

Yes

Yes

Yes

IRR, incidence rate ratio; CI, confidence interval; IR, incidence rate; PPPY, per-person per-year; SAE, serious adverse event

* Comparative analysis of effectiveness, as measured by first observed improvement in BASP classification, among patients prescribed the recommended doses of dutasteride (0.5 mg daily) and finasteride (1 mg daily).

** Equivalence was determined from two one-sided tests to determine whether the 90% confidence interval for the differences in proportions were within the equivalence region, defined as ±5%.

Multivariate models were adjusted for age at index date, study site, index year, recent hair loss at baseline, comorbidities at baseline, use of treatment during baseline, and baseline severity of AGA.

Adverse Events

Study Author Conclusions

Dutasteride showed greater effectiveness than finasteride in improving BASP classification in treating male AGA and had a similar or possibly lower occurrence of overall AEs. Dutasteride may provide an effective and safe treatment option for male patients with AGA.

InpharmD Researcher Critique

A randomized, active- and placebo-controlled study of the efficacy and safety of different doses of dutasteride versus placebo and finasteride in the treatment of male subjects with androgenetic alopecia

Design

Randomized, double-blind, double-dummy, parallel-group trial 

N= 917

Objective

To compare the efficacy and safety of dutasteride (type 1 and 2 5-alpha reductase inhibitor) with finasteride (type 2 5-alpha reductase inhibitor) and placebo in men with androgenetic alopecia

Study Groups

Placebo (n= 181)

Dutasteride 0.02 mg (n= 185)

Dutasteride 0.1 mg (n= 188)

Dutasteride 0.5 mg (n= 184)

Finasteride 1 mg (n= 179)

Inclusion Criteria

Exclusion Criteria

Methods

Patients were randomized in a 1:1:1:1:1 ratio to receive either dutasteride 0.02, 0.1, or 0.5 mg/day, finasteride 1 mg/day, or a matched placebo for 24 weeks of treatment. Investigators, treating physicians, and patients were blinded to treatment allocation until the study was completed or until a patient withdrew due to a serious adverse event. 

Duration

Intervention: 24 weeks

Follow-up: 2 weeks

Outcome Measures

Primary: Change from baseline in hair count within a 2.54-cm diameter circle at the vertex at 24 weeks

Secondary: Change from baseline in hair count within a 2.54-cm diameter circle at 12 weeks; 1.13 cm diameter circle at the vertex at 12 and 24 weeks); hair restoration (change from baseline in hair width and terminal hair [thickness of ≥ 60 μm] count within a 2.54 and 1.13 cm diameter circle at the vertex [12 and 24 weeks])

Baseline Characteristics

Placebo

(n= 181)

Dutasteride 0.02 mg

(n= 185)

Dutasteride 0.1 mg

(n= 188)

Dutasteride 0.5 mg

(n= 184) 

Finasteride 1 mg

(n= 179) 

Age, years

Male

Race

Asian

Hispanic/Latino

White, not Hispanic

100 (55%)

72 (40%)

9 (5%) 

103 (56%)

71 (38%)

11 (6%) 

103 (55%) 

75 (40%)

10 (5%)

101 (55%) 

73 (40%)

10 (5%) 

100 (56%)

70 (39%)

9 (5%)

Body mass index, kg/m²

Smoking status

Current smoker

Former smoker

55 (30%) 

26 (14%)

70 (38%) 

25 (14%) 

70 (37%) 

29 (15%)

50 (27%) 

33 (18%)

59 (33%)

24 (13%)

Consume alcohol

120 (67%) 

118 (64%) 

119 (63%) 

121 (66%) 

117 (65%)

Age hair loss first noticed, years

29.0 ± 7.84

29.9 ± 8.06 

28.4 ± 6.79 

29.6 ± 7.73 

29.8 ± 7.45

Currently experiencing hair loss

151 (83%) 

152 (82%) 

161 (86%) 

160 (87%) 

154 (86%)

Baseline Norwood Hamilton stage

III Vertex

IV

V

82 (45%) 

56 (31%)

43 (24%) 

77 (42%) 

61 (33%)

47 (25%) 

76 (40%)

65 (35%)

47 (25%) 

83 (45%) 

58 (32%)

43 (23%) 

79 (44%)

59 (33%)

41 (23%)

Baseline hair count 2.54 cm diameter

761 ± 227

774 ± 226

721 ± 220 

768 ± 218

764 ± 181

Baseline hair count 1.13 cm diameter

Results

Endpoint

Placebo

(n= 181)

Dutasteride 0.02 mg

(n= 185)

Dutasteride 0.1 mg

(n= 188)

Dutasteride 0.5 mg

(n= 184)

Finasteride 1 mg

(n= 179)

Any drug-related AE

Any SAE*

Death

Common AEs**

Nasopharyngitis

Decreased libido 

Headache 

Erectile dysfunction 

Abdominal pain 

Upper respiratory tract infection 

Back pain 

Upper abdominal pain 

Influenza 

Diarrhea 

Allergic rhinitis 

Pharyngitis

16 (9%) 

2 (1%) 

16 (9%)

7 (4%)

2 (1%)

9 (5%)

4 (2%)

1 (<1%)

5 (3%)

3 (2%)

1 (<1%)

7 (4%)

19 (10%) 

10 (5%) 

8 (4%)

8 (4%)

6 (3%)

5 (3%)

5 (3%)

4 (2%)

3 (2%)

2 (1%)

2 (1%)

1 (<1%)

15 (8%) 

9 (5%) 

8 (4%)

7 (4%)

7 (4%)

2 (1%)

3 (2%)

1 (<1%)

4 (2%)

7 (4%)

1 (<1%)

2 (1%)

23 (13%) 

6 (3%) 

11 (6%)

10 (5%) 

2 (1%)

6 (3%)

3 (2%)

2 (1%)

1 (<1%)

2 (1%)

4 (2%)

3 (2%)

14 (8%)

9 (5%)

5 (3%)

10 (6%) 

2 (1%)

1 (<1%)

4 (2%)

5 (3%)

2 (1%)

0

6 (3%)

5 (3%)

Abbreviations: adverse event; SAE, serious adverse event

*SAEs were: syncope and nephrolithiasis in the placebo group; cartilage injury, rectal cancer, increased blood pressure, and metastatic hepatic cancer in the dutasteride 0.1 mg group; parasitic infection, salmonellosis, and gastric ulcer 

**≥3% in any group

At week 24, the increase in baseline hair count was significantly greater in the dutasteride 0.1 mg, dutasteride 0.5 mg, and finasteride groups compared to placebo (all p < 0.001). Dutasteride 0.1 mg and 0.5 mg were non-inferior to finasteride (1-sided 99.165% confidence intervals: -20.1 to 33.1 and 6.1 to 60.0, respectively). However, only dutasteride 0.5 mg was superior to finasteride at both weeks 12 and 24 (both p = 0.003). Findings were provided within the figures.

At week 24, all active treatment groups except dutasteride 0.02 mg were significantly superior to placebo in increasing hair count measured in 1.13 cm diameter areas. (all p < 0.001). Dutasteride 0.5 mg significantly increased hair count compared to finasteride (p = 0.016). Findings were provided within the figures.

For hair restoration, at week 24, dutasteride 0.1 mg, dutasteride 0.5 mg, and finasteride were all significantly more effective than placebo in increasing hair width (2.54 cm diameter) (all p < 0.001). Dutasteride 0.5 mg also significantly increased hair width compared to finasteride (p = 0.004). Findings were provided within figures. 

Adverse Events

Study Author Conclusions

Dutasteride increased hair growth and restoration in men with androgenetic alopecia and was relatively well tolerated.

InpharmD Researcher Critique

The importance of dual 5a-reductase inhibition in the treatment of male pattern hair loss: Results of a randomized placebo-controlled study of dutasteride versus finasteride

Design

Randomized, placebo-controlled study

N= 416

Objective

To evaluate the efficacy of the type 1 and 2 5a-reductase inhibitor dutasteride in men with male pattern hair loss (MPHL)

Study Groups

Dutasteride (n= 346)

Finasteride (n= 70)

Inclusion Criteria

Men aged 21 to 45 years old, with mild-to-moderate MPHL, having never used a 5a-reductase inhibitor or any medication for alopecia during the previous 6 months, with no significant health problems and no use of androgenic or antiandrogenic drugs during previous 6 months

Exclusion Criteria

Not specified

Methods

Patients were randomized to treatment with dutasteride (0.05, 0.1, 0.5, or 2.5 mg), finasteride (5 mg), or placebo daily for 24 weeks. Finasteride 5 mg was utilized at the time of the study since 1 mg dose was not commercially available at the time of the study.  Furthermore, the 5-mg dose of finasteride had previously been shown to have efficacy in MPHL at least as great as the 1 mg dose.

Duration

Treatment: 24 weeks

Outcome Measures

Primary: hair regrowth via target area hair count

Secondary: exploratory assessment of hair count, panel assessment of improvement from baseline, investigators’ assessment of improvement, subjects’ global assessment of improvement (via self-assessment questionnaire at 24 weeks), and stage of MPHL using the modified Hamilton-Norwood classification

Baseline Characteristics

All patients (N= 416)

Age, years

938.5 ± 251.7

Age at first balding, years

Stage of MPHL

III vertex

IV

IVa

V

169 (41%)

131 (31%)

19 (5%)

97 (23%)

There were no significant differences in the groups with respect to age, race or degree of baldness.

Results

Endpoint

Placebo

Dutasteride 0.05 mg

Dutasteride 0.1 mg

Dutasteride 0.5 mg

Dutasteride 2.5 mg

Finasteride 5.0 mg

Mean changes in hair count vs. baseline

12 weeks

24 weeks

-26.5

-32.3

N/A*

N/A** 

55**

78.5**

71.3**

94.6**

99.9**‡

109.6**†

52.1**

75.6**

≥ 10% increase in hair counts at 24 weeks

Expert panel assessment of global photographs at 24 weeks - vertex

No change

Slightly increased

Moderately increased

Greatly increased

91%

0

2%

0

75%

12%

3%

0 

61%

33%

7%

0 

37%

40%

21%

2%

22%

48%

28%

1% 

43%

48%

9%

0

Expert panel assessment of global photographs at 24 weeks - frontal

No change

Slightly increased

Moderately increased

Greatly increased

87% 

12%

0

0

73%

20% 

2%

0

67%

30% 

3%

0

52%

30% 

18%

0

37%

36% 

25%

0

52%

36%

9% 

0

Overall patient satisfaction

42%

58%

57%

56%

61%¥

*p≤ 0.5 vs. placebo

**p≤ 0.001 vs. placebo

‡p≤ 0.001 vs. finasteride

†p≤ 0.05 vs. finasteride

¥p< 0.05 vs. placebo

For expert panel global photographs, dutasteride 0.5 mg showed a significantly greater improvement than finasteride at 24 weeks (P p= 0.026), whereas dutasteride 2.5 mg showed significantly greater improvements than finasteride at both 12 and 24 weeks (p< 0.001). 

Adverse Events

Study Author Conclusions

In conclusion, 2.5-mg dutasteride, a dual 5a-reductase inhibitor, improved hair growth in balding men more rapidly and to a greater degree than finasteride, a selective type 2 inhibitor. Dutasteride was generally well tolerated. The results of this study demonstrate the significant additive effect of inhibiting both type 1 and type 2 5a-reductase in the treatment of MPHL.

InpharmD Researcher Critique

This was a phase II, dose-ranging study, although the study included a large number of subjects. Additionally, the study's duration was restricted to 24 weeks which may not capture long-term effects or trends, potentially affecting the comprehensiveness and applicability of the findings over a longer timeframe.