Data from the Sophia trial of Macrogenics’ margetuximab, presented at the San Antonio Breast Cancer Symposium today, underline what was already fairly clear: of the anti-Her2 projects intended to be a “better Herceptin”, Astrazeneca and Daiichi Sankyo’s antibody-drug conjugate, trastuzumab deruxtecan, is way out ahead. Margetuximab could show no overall survival advantage over Herceptin at the second interim analysis of Sophia data, with a median OS of 21.6 months versus 19.8 months for Roche’s drug. The final pre-specified OS analysis of Sophia is expected in the second half of 2020, by which time trastuzumab deruxtecan will almost certainly be approved in the third-line setting. The table below summarises data from various studies conducted in late-line breast cancer patients, and while such a comparison is imperfect it clearly shows trastuzumab deruxtecan trouncing the others. It also shows that the sellside has made up its mind in terms of which horse to back.
|Cross-trial comparison of anti-Her agents|
|Company||Agent||Trial||ORR||Median PFS (months)||Median DoR (months)||2024e WW sales|
|ORR=objective response rate. PFS=progression-free survival. DoR=duration of response.
Source: EvaluatePharma; NEJM; company statements; SABCS.