Adjuvant Therapy
The data described below reflect exposure to exemestane tablets in 2325 postmenopausal women with early breast cancer. Exemestane tablets tolerability in postmenopausal women with early breast cancer was evaluated in two well-controlled trials: the IES study [See Clinical Studies (14.1)] and the 027 study (a randomized, placebo-controlled, double-blind, parallel group study specifically designed to assess the effects of exemestane on bone metabolism, hormones, lipids, and coagulation factors over 2 years of treatment).
The median duration of adjuvant treatment was 27.4 months and 27.3 months for patients receiving exemestane tablets or tamoxifen, respectively, within the IES study and 23.9 months for patients receiving exemestane tablets or placebo within the 027 study. Median duration of observation after randomization for exemestane tablets was 34.5 months and for tamoxifen was 34.6 months. Median duration of observation was 30 months for both groups in the 027 study.
Certain adverse reactions, which were expected based on the known pharmacological properties and side effect profiles of test drugs, were actively sought through a positive checklist. Signs and symptoms were graded for severity using CTC in both studies. Within the IES study, the presence of some illnesses/conditions was monitored through a positive checklist without assessment of severity. These included myocardial infarction, other cardiovascular disorders, gynecological disorders, osteoporosis, osteoporotic fractures, other primary cancer, and hospitalizations.
Within the IES study, discontinuations due to adverse reactions occurred in 6% and 5% of patients receiving exemestane tablets and tamoxifen, respectively, and in 12% and 4.1% of patients receiving exemestane or placebo respectively within study 027.
Deaths due to any cause were reported for 1.3% of the exemestane treated patients and 1.4% of the tamoxifen treated patients within the IES study. There were 6 deaths due to stroke on the exemestane arm compared to 2 on tamoxifen. There were 5 deaths due to cardiac failure on the exemestane arm compared to 2 on tamoxifen.
The incidence of cardiac ischemic events (myocardial infarction, angina, and myocardial ischemia) was 1.6% in exemestane treated patients and 0.6% in tamoxifen treated patients in the IES study. Cardiac failure was observed in 0.4% of exemestane treated patients and 0.3% of tamoxifen treated patients.
In the adjuvant treatment of early breast cancer, the most common adverse reactions occurring in ≥10% of patients in any treatment group (exemestane tablets vs. tamoxifen) were hot flushes (21% vs. 20%), fatigue (16% vs. 15%), arthralgia (15% vs. 9%), headache (13% vs. 11%), insomnia (12% vs. 9%), and increased sweating (12% vs. 10%). Discontinuation rates due to AEs were similar between exemestane tablets and tamoxifen (6% vs. 5%). Incidences of cardiac ischemic events (myocardial infarction, angina, and myocardial ischemia) were exemestane tablets 1.6%, tamoxifen 0.6%. Incidence of cardiac failure: exemestane tablets 0.4%, tamoxifen 0.3%.
Treatment-emergent adverse reactions and illnesses including all causalities and occurring with an incidence of ≥5% in either treatment group of the IES study during or within one month of the end of treatment are shown in Table 2.
Table 2. Incidence (%) of Adverse Reactions of all Grades and Illnesses Occurring in (≥5%) of Patients in Any Treatment Group in Study IES in Postmenopausal Women with Early Breast Cancer | % of patients |
|---|
| Body system and Adverse Reaction by MedDRA dictionary | Exemestane Tablets 25 mg daily (N=2252) | Tamoxifen 20 mg daily
(N=2280) |
|---|
| Eye | | |
| Visual disturbances
| 5 | 3.8 |
| Gastrointestinal | | |
| Nausea
| 9 | 9 |
| General Disorders | | |
| Fatigue
| 16 | 15 |
| Musculoskeletal | | |
| Arthralgia | 15 | 9 |
| Pain in limb | 9 | 6 |
| Back pain | 9 | 7 |
| Osteoarthritis | 6 | 4.5 |
| Nervous System | | |
| Headache
| 13 | 11 |
| Dizziness
| 10 | 8 |
| Psychiatric | | |
| Insomnia
| 12 | 9 |
| Depression | 6 | 6 |
| Skin & Subcutaneous Tissue | | |
| Increased sweating
| 12 | 10 |
| Vascular | | |
| Hot flushes
| 21 | 20 |
| Hypertension | 10 | 8 |
In the IES study, as compared to tamoxifen, exemestane tablets were associated with a higher incidence of events in musculoskeletal disorders and in nervous system disorders, including the following events occurring with frequency lower than 5% (osteoporosis [4.6% vs. 2.8%], osteochondrosis and trigger finger [0.3% vs. 0% for both events], paresthesia [2.6% vs. 0.9%], carpal tunnel syndrome [2.4% vs. 0.2%], and neuropathy [0.6% vs. 0.1%]). Diarrhea was also more frequent in the exemestane group (4.2% vs. 2.2%). Clinical fractures were reported in 94 patients receiving exemestane (4.2%) and 71 patients receiving tamoxifen (3.1%). After a median duration of therapy of about 30 months and a median follow-up of about 52 months, gastric ulcer was observed at a slightly higher frequency in the exemestane tablets group compared to tamoxifen (0.7% vs. <0.1%). The majority of patients on exemestane tablets with gastric ulcer received concomitant treatment with non-steroidal anti-inflammatory agents and/or had a prior history.
Tamoxifen was associated with a higher incidence of muscle cramps [3.1% vs. 1.5%], thromboembolism [2.0% vs. 0.9%], endometrial hyperplasia [1.7% vs. 0.6%], and uterine polyps [2.4% vs. 0.4%].
Common adverse reactions occurring in study 027 are described in Table 3.
Table 3. Incidence of Selected Treatment-Emergent Adverse Reactions of all CTC Grades Occurring in ≥5% of Patients in Either Arm in Study 027| Adverse Reaction | Exemestane N=73 (% incidence) | Placebo N=73 (% incidence) |
|---|
| Hot flushes | 33 | 25 |
| Arthralgia | 29 | 29 |
| Increased sweating | 18 | 21 |
| Alopecia | 15 | 4.1 |
| Hypertension | 15 | 7 |
| Insomnia | 14 | 15 |
| Nausea | 12 | 16 |
| Fatigue | 11 | 19 |
| Abdominal pain | 11 | 14 |
| Depression | 10 | 7 |
| Diarrhea | 10 | 1.4 |
| Dizziness | 10 | 10 |
| Dermatitis | 8 | 1.4 |
| Headache | 7 | 4.1 |
| Myalgia | 6 | 4.1 |
| Edema | 6 | 7 |