Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice.

HER2-Positive Metastatic Breast Cancer: The safety of TYKERB has been evaluated in more than 12,000 patients in clinical trials. The efficacy and safety of TYKERB in combination with capecitabine in breast cancer was evaluated in 198 patients in a randomized, Phase 3 trial [see Clinical Studies (14.1)]. Adverse reactions, which occurred in at least 10% of patients in either treatment arm and were higher in the combination arm, are shown in Table 1.

The most common adverse reactions (greater than 20%) during therapy with TYKERB plus capecitabine were gastrointestinal (diarrhea, nausea, and vomiting), dermatologic (palmar-plantar erythrodysesthesia and rash), and fatigue. Diarrhea was the most common adverse reaction resulting in discontinuation of study medication.

The most common Grades 3 and 4 adverse reactions (NCI CTCAE v3.0) were diarrhea and palmar-plantar erythrodysesthesia. Selected laboratory abnormalities are shown in Table 2.

Hormone Receptor-Positive, Metastatic Breast Cancer: In a randomized, Phase 3 clinical trial of patients (N = 1286) with hormone receptor-positive, metastatic breast cancer, who had not received chemotherapy for their metastatic disease, patients received letrozole with or without TYKERB. In this trial, the safety profile of TYKERB was consistent with previously reported results from trials of TYKERB in the advanced or metastatic breast cancer population. Adverse reactions, which occurred in at least 10% of patients in either treatment arm and were higher in the combination arm are shown in Table 3. Selected laboratory abnormalities are shown in Table 4.

Hormone Receptor-Positive, HER2+ Metastatic Breast Cancer: In another randomized, Phase 3 clinical trial of postmenopausal patients (N = 355) with hormone receptor positive (HR+), HER2-positive metastatic breast cancer (MBC) which had progressed after prior trastuzumab-containing chemotherapy and endocrine therapies, patients received TYKERB with trastuzumab and an aromatase inhibitor (AI) (letrozole, exemestane, or anastrozole), TYKERB with an AI, or trastuzumab with an AI. In this trial, the safety profile of the treatment groups was consistent with the known safety of these agents. The most frequent study treatment-related AEs (> 10%) in each of the TYKERB-containing treatment arms were diarrhea, rash, paronychia, nausea, stomatitis, dermatitis acneiform, and decreased appetite, which were infrequent to absent in the trastuzumab treatment arm. The frequency of cardiac AEs (mostly decrease in ejection fraction) was 7% in the TYKERB+trastuzumab+AI group, 2% in the TYKERB+AI group and 3% in the trastuzumab+AI group. Adverse reactions which occurred in at least 10% of patients in the treatment arms are shown in Table 5.

Decreases in Left Ventricular Ejection Fraction: Due to potential cardiac toxicity with HER2 (ErbB2) inhibitors, LVEF was monitored in clinical trials at approximately 8-week intervals. LVEF decreases were defined as signs or symptoms of deterioration in left ventricular cardiac function that are greater than or equal to Grade 3 (NCI CTCAE v3.0), or a greater than or equal to 20% decrease in left ventricular cardiac ejection fraction relative to baseline which is below the institution's lower limit of normal. Among 198 patients who received combination treatment with TYKERB/capecitabine, 3 experienced Grade 2 and one had Grade 3 LVEF adverse reactions (NCI CTCAE v3.0). Among 654 patients who received combination treatment with TYKERB/letrozole, 26 patients experienced Grade 1 or 2 and 6 patients had Grade 3 or 4 LVEF adverse reactions [see Warnings and Precautions (5.1)].

Hepatotoxicity: TYKERB has been associated with hepatotoxicity [see Boxed Warning and Warnings and Precautions (5.2)]. 

Interstitial Lung Disease/Pneumonitis: TYKERB has been associated with ILD and pneumonitis in monotherapy or in combination with other chemotherapies [see Warnings and Precautions (5.5)].