Trial Outcomes & Findings for Aromatase Inhibitor Growth Study: Letrozole vs. Anastrozole (NCT NCT02137538)

NCT ID: NCT02137538

Last Updated: 2021-07-15

Results Overview

Heights will be obtained by physical exam every 6 months during treatment. Skeletal maturation will be assessed from an x-ray by the method of Greulich and Pyle at baseline and every 12 months until the end of treatment. Predicted adult height will be calculated at baseline and at the end of treatment based upon measured height and skeletal maturation (bone age).

Recruitment status

COMPLETED

Study phase

PHASE4

Target enrollment

79 participants

Primary outcome timeframe

Year 3

Results posted on

2021-07-15

Participant Flow

Participant milestones

Participant milestones
Measure	Letrozole Participants receive letrozole 2.5 mg daily	Anastrozole Participants receive anastrozole 1 mg daily
Overall Study STARTED	39	40
Overall Study COMPLETED	23	26
Overall Study NOT COMPLETED	16	14

Reasons for withdrawal

Withdrawal data not reported

Baseline Characteristics

Race and Ethnicity were not collected from any participant.

Baseline characteristics by cohort

Baseline characteristics by cohort
Measure	Letrozole n=30 Participants Participants receive letrozole 2.5 mg daily	Anastrozole n=35 Participants Participants receive anastrozole 1 mg daily	Total n=65 Participants Total of all reporting groups
Age, Continuous	13.9 years STANDARD_DEVIATION 1.2 • n=30 Participants	13.9 years STANDARD_DEVIATION 1.5 • n=35 Participants	13.9 years STANDARD_DEVIATION 1.4 • n=65 Participants
Sex: Female, Male Female	0 Participants n=30 Participants	0 Participants n=35 Participants	0 Participants n=65 Participants
Sex: Female, Male Male	30 Participants n=30 Participants	35 Participants n=35 Participants	65 Participants n=65 Participants
Race and Ethnicity Not Collected	—	—	0 Participants Race and Ethnicity were not collected from any participant.
Region of Enrollment United States	30 participants n=30 Participants	35 participants n=35 Participants	65 participants n=65 Participants
Bone age	156.1 months STANDARD_DEVIATION 6.6 • n=30 Participants	156.3 months STANDARD_DEVIATION 12.2 • n=35 Participants	156.2 months STANDARD_DEVIATION 9.9 • n=65 Participants
Predicted Adult Height	167.2 cm STANDARD_DEVIATION 5.8 • n=30 Participants	167.3 cm STANDARD_DEVIATION 6.9 • n=35 Participants	167.2 cm STANDARD_DEVIATION 6.4 • n=65 Participants

PRIMARY outcome

Timeframe: Year 3

Population: Participants who finished the first year of therapy are included in the analysis, excluding participants who had received growth hormone.

Heights will be obtained by physical exam every 6 months during treatment. Skeletal maturation will be assessed from an x-ray by the method of Greulich and Pyle at baseline and every 12 months until the end of treatment. Predicted adult height will be calculated at baseline and at the end of treatment based upon measured height and skeletal maturation (bone age).

Outcome measures

Outcome measures
Measure	Letrozole n=30 Participants Participants receive letrozole 2.5 mg daily	Anastrozole n=35 Participants Participants receive anastrozole 1 mg daily
Predicted Adult Height at Year 3	167.8 cm Standard Deviation 5.8	169.4 cm Standard Deviation 5.1

SECONDARY outcome

Timeframe: Baseline, year 3

Population: Participants who finished the first year of therapy are included in the analysis, excluding participants who had received growth hormone.

Outcome measures

Outcome measures
Measure	Letrozole n=30 Participants Participants receive letrozole 2.5 mg daily	Anastrozole n=35 Participants Participants receive anastrozole 1 mg daily
Serum Testosterone Baseline	213.1 ng/dL Standard Deviation 133.7	162.1 ng/dL Standard Deviation 124.6
Serum Testosterone Year 3	882.3 ng/dL Standard Deviation 250.5	680.1 ng/dL Standard Deviation 179.5

SECONDARY outcome

Timeframe: Baseline, year 3

Population: Participants who finished the first year of therapy are included in the analysis, excluding participants who had received growth hormone.

Outcome measures

Outcome measures
Measure	Letrozole n=30 Participants Participants receive letrozole 2.5 mg daily	Anastrozole n=35 Participants Participants receive anastrozole 1 mg daily
Dihydrotestosterone Baseline	22.5 ng/dL Standard Deviation 11.3	19.1 ng/dL Standard Deviation 9.7
Dihydrotestosterone Year 3	65.0 ng/dL Standard Deviation 20.2	44.1 ng/dL Standard Deviation 23.5

SECONDARY outcome

Timeframe: Baseline, year 3

Population: Participants who finished the first year of therapy are included in the analysis, excluding participants who had received growth hormone.

Outcome measures

Outcome measures
Measure	Letrozole n=30 Participants Participants receive letrozole 2.5 mg daily	Anastrozole n=35 Participants Participants receive anastrozole 1 mg daily
Androstenedione Baseline	35.3 ng/dL Standard Deviation 13.1	37.4 ng/dL Standard Deviation 21.4
Androstenedione Year 3	79.9 ng/dL Standard Deviation 21.5	77.9 ng/dL Standard Deviation 28.2

SECONDARY outcome

Timeframe: Baseline, year 3

Population: Participants who finished the first year of therapy are included in the analysis, excluding participants who had received growth hormone.

Outcome measures

Outcome measures
Measure	Letrozole n=30 Participants Participants receive letrozole 2.5 mg daily	Anastrozole n=35 Participants Participants receive anastrozole 1 mg daily
Luteinizing Hormone Baseline	2.3 mIU/mL Standard Deviation 1.5	1.8 mIU/mL Standard Deviation 1.1
Luteinizing Hormone Year 3	4.7 mIU/mL Standard Deviation 1.9	3.4 mIU/mL Standard Deviation 2.0

SECONDARY outcome

Timeframe: Baseline, year 3

Population: Participants who finished the first year of therapy are included in the analysis, excluding participants who had received growth hormone.

Outcome measures

Outcome measures
Measure	Letrozole n=30 Participants Participants receive letrozole 2.5 mg daily	Anastrozole n=35 Participants Participants receive anastrozole 1 mg daily
Follicle Stimulating Hormone Baseline	3.3 mIU/mL Standard Deviation 1.9	2.5 mIU/mL Standard Deviation 1.3
Follicle Stimulating Hormone Year 3	6.6 mIU/mL Standard Deviation 2.4	4.5 mIU/mL Standard Deviation 2.9

SECONDARY outcome

Timeframe: Baseline, year 3

Population: Participants who finished the first year of therapy are included in the analysis, excluding participants who had received growth hormone.

Outcome measures

Outcome measures
Measure	Letrozole n=30 Participants Participants receive letrozole 2.5 mg daily	Anastrozole n=35 Participants Participants receive anastrozole 1 mg daily
Insulin-like Growth Factor Type 1 Baseline	306.2 ng/mL Standard Deviation 112.8	306.9 ng/mL Standard Deviation 112.9
Insulin-like Growth Factor Type 1 Year 3	226.1 ng/mL Standard Deviation 54.4	298.7 ng/mL Standard Deviation 78.8

SECONDARY outcome

Timeframe: Baseline, year 3

Population: Participants who finished the first year of therapy are included in the analysis, excluding participants who had received growth hormone.

Outcome measures

Outcome measures
Measure	Letrozole n=30 Participants Participants receive letrozole 2.5 mg daily	Anastrozole n=35 Participants Participants receive anastrozole 1 mg daily
Inhibin B Baseline	203.4 pg/mL Standard Deviation 55.0	217.0 pg/mL Standard Deviation 65.2
Inhibin B Year 3	257.6 pg/mL Standard Deviation 61.1	262.1 pg/mL Standard Deviation 97.9

SECONDARY outcome

Timeframe: Baseline, year 3

Population: Participants who finished the first year of therapy are included in the analysis, excluding participants who had received growth hormone.

Outcome measures

Outcome measures
Measure	Letrozole n=30 Participants Participants receive letrozole 2.5 mg daily	Anastrozole n=35 Participants Participants receive anastrozole 1 mg daily
Estradiol Baseline	4.9 pg/mL Standard Deviation 3.6	4.7 pg/mL Standard Deviation 4.7
Estradiol Year 3	2.7 pg/mL Standard Deviation 2.1	6.2 pg/mL Standard Deviation 2.5

SECONDARY outcome

Timeframe: Baseline, year 3

Population: Participants who finished the first year of therapy are included in the analysis, excluding participants who had received growth hormone.

Outcome measures

Outcome measures
Measure	Letrozole n=30 Participants Participants receive letrozole 2.5 mg daily	Anastrozole n=35 Participants Participants receive anastrozole 1 mg daily
Estrone Baseline	8.7 pg/mL Standard Deviation 4.8	8.0 pg/mL Standard Deviation 4.9
Estrone Year 3	2.7 pg/mL Standard Deviation 0.3	3.5 pg/mL Standard Deviation 3.2

SECONDARY outcome

Timeframe: 3 years

Population: Participants who finished the first year of therapy are included in the analysis, excluding participants who had received growth hormone.

Outcome measures

Outcome measures
Measure	Letrozole n=30 Participants Participants receive letrozole 2.5 mg daily	Anastrozole n=35 Participants Participants receive anastrozole 1 mg daily
Number of Adverse Events Related to Acne or Bone Fracture Acne	3 events	3 events
Number of Adverse Events Related to Acne or Bone Fracture Fracture	3 events	5 events

Adverse Events

Letrozole

Serious events: 0 serious events

Other events: 12 other events

Deaths: 0 deaths

Anastrozole

Serious events: 2 serious events

Other events: 10 other events

Deaths: 0 deaths

Serious adverse events

Serious adverse events
Measure	Letrozole n=39 participants at risk Participants receive letrozole 2.5 mg daily	Anastrozole n=40 participants at risk Participants receive anastrozole 1 mg daily
Musculoskeletal and connective tissue disorders Sacroiliitis	0.00% 0/39 • 3 years	2.5% 1/40 • Number of events 1 • 3 years
Nervous system disorders Neuro event	0.00% 0/39 • 3 years	2.5% 1/40 • Number of events 1 • 3 years

Other adverse events

Other adverse events
Measure	Letrozole n=39 participants at risk Participants receive letrozole 2.5 mg daily	Anastrozole n=40 participants at risk Participants receive anastrozole 1 mg daily
Injury, poisoning and procedural complications Fracture	7.7% 3/39 • Number of events 3 • 3 years	10.0% 4/40 • Number of events 5 • 3 years
Musculoskeletal and connective tissue disorders Scoliosis	2.6% 1/39 • Number of events 1 • 3 years	5.0% 2/40 • Number of events 2 • 3 years
Nervous system disorders Aggression	2.6% 1/39 • Number of events 1 • 3 years	0.00% 0/40 • 3 years
Skin and subcutaneous tissue disorders Acne	7.7% 3/39 • Number of events 3 • 3 years	7.5% 3/40 • Number of events 3 • 3 years
Skin and subcutaneous tissue disorders Hair loss	10.3% 4/39 • Number of events 4 • 3 years	2.5% 1/40 • Number of events 1 • 3 years

Additional Information

E Kirk Neely

Stanford University

Phone: 650-723-5791

Email: [email protected]

Results disclosure agreements

Principal investigator is a sponsor employee
Publication restrictions are in place