Pfizer data indicates differences between steroidal and non-steroidal aromatase inhibitors

In a presentation at the 10th International Conference on Adjuvant Therapy of Primary Breast Cancer in St Gallen, Switzerland, US drug major Pfizer challenged the perception that aromatase inhibitors have a class effect. It argued that an emerging body of evidence suggests the differing mechanisms of action of non-steroidal and steroidal drugs in this group have markedly different therapeutic effects.

EFECT study highlights differences in class

The opinion is based on data from a trial of the firm's steroidal aromatase inhibitor Aromasin (exemestane), which was designed to compare the effect of the drug with that of fulvestrant, a selective estrogen receptor down regulator (SERD), in women with metastatic breast cancer who have failed on an AI in the adjuvant or first-line setting.