- AstraZeneca and Daiichi Sankyo's breast cancer drug trastuzumab deruxtecan scored positive results in a trial of metastatic breast cancer patients with recurrent disease following treatment with Roche's Kadcyla. Trastuzumab deruxtecan had "unprecedented clinical activity" in an open-label trial that measured remission rates, although the companies did not disclose detailed data.
- A Food and Drug Administration submission is planned for later this year, which, if successful, would give oncologists a fourth agent targeting HER-positive disease.
- AstraZeneca paid Daiichi Sankyo $1.35 billion upfront earlier this year and promised up to $6.9 billion in total to secure rights to trastuzumab deruxtecan. The U.K. company sold $3.5 billion in shares to fund the deal.
For the second day in a row, AstraZeneca had good news from its oncology pipeline. Trastuzumab deruxtecan is being positioned to treat a population of breast-cancer patients with very advanced disease and few treatment options.
The agent is an antibody-drug conjugate that combines the active ingredient from Roche's early-stage breast cancer drug Herceptin (trastuzumab) with a cytotoxic molecule, deruxtecan. Trastuzumab binds with tumor cells expressing the protein HER2. Roche's Kadcyla (ado-trastuzumab emtansine) works similarly, but delivers a different cytotoxic agent.
AstraZeneca no doubt was attracted to the Daiichi project because of recently published Phase 1 data showing that it achieved partial or complete remission in 60% of patients and kept them from progressing for an average of a little more than 22 months.
That trial was in 115 patients. The results announced today were from DESTINY-Breast01, in 230 patients. The aims of the two-part Phase 2 trial were to first identify an optimal dose, and then measure clinical benefit in patients receiving that dose.
Given the price of the transaction and the share dilution, there may have been some investor relief today. The pharma's London-traded shares closed up a little more than 1%. On the day the deal was announced, they fell 6%, and today they stand 11% below the pre-Daiichi deal levels.
Approval in a late-line breast cancer setting probably isn't going to be enough to fully satisfy investors. As happens frequently in oncology, the two partners are looking to move trastuzumab deruxtecan into earlier treatment lines and into other diseases in which HER2 targeting is relevant.
To that end, the partners now have trastuzumab deruxtecan in a head-to-head trial against Kadcyla, as well as colorectal and non-small cell lung cancers. If these tests come up positive, investors may become a bit more enthusiastic about AstraZeneca's strategy in HER2 disease.