The European Medicines Agency (EMA) has accelerated the assessment of Daiichi Sankyo and AstraZeneca’s HER2-positive breast cancer candidate, fast-tracking its potential approval in the EU.
AZ/Daiichi’s drug gained US Food and Drug Administration (FDA) approval for trastuzumab deruxtecan in December under the brand name Enhertu. The antibody drug conjugate was cleared for the treatment of metastatic HER2-positive disease in patients who have been previously treated with two or more anti-HER2 based regimens.
The partner companies are seeking to gain approval for the drug in the same indication in Europe, with this accelerated assessment indicating the beginning of the scientific review process by the EMA’s Committee for Medicinal Products for Human Use (CHMP).
The drug presents a new challenge to Roche’s dominant position in the HER2-positive breast cancer market, which includes a trio of targeted treatments – Herceptin (trastuzumab), Perjeta (pertuzumab) and Kadcyla (trastuzumab emtansine).
Although AZ/Daiichi’s drug is set to compete most closely with Kadcyla as a later-line therapy, the partners are eager to move into earlier treatment settings, with the approval in the US and the likely approval in the EU soon a clear signal of this.
The FDA approval and EMA application include data from the DESTINY-Breast01 trial in patients who had previously been treated with Herceptin, Perjeta or Kadcyla. AZ/Daiichi’s drug achieved a 60% objective response rate, including just over 4% complete responses, with a median duration of response of 14.8 months.
They are also conducting three further phase 3 trials of trastuzumab deruxtecan in HER2-positive breast and gastric cancer settings, as well as in low HER2-expressing tumours that could help to expand potential markets for the drug.
AZ agreed on a $6.9bn deal with Daiichi for the drug in March last year, which included a massive $1.35bn upfront payment. The remaining payments are tied to future regulatory and development milestones, and further payments have been pledged if the drug meets sales targets. That included a $125m payment to Daiichi from AZ following the US approval last year, which marked the first of those milestone payments.
The companies have split the cost of bringing the drug to market and will share in global profits, with the exception of Japan where Daiichi retains exclusive rights.
Analysts have predicated that AZ/Daiichi’s drug could overtake Kadcyla and become a multibillion-dollar therapy, with some pegging the potential at up to $12bn at its peak. Trastuzumab deruxtecan is central to Daiichi’s growth efforts, and is also a key drug for AZ’s cancer franchise.