Astrazeneca's breast cancer drug Enhertu shows better efficacy in preventing recurrence compared to competitors and is expected to cure early-stage patients

According to the Zhitong Finance APP, AstraZeneca (AZN.US) and Japanese pharmaceutical company Daiichi Sankyo's cancer drug Enhertu has brought better treatment outcomes for early-stage breast cancer patients. These results could potentially allow this best-selling drug to benefit more patients and bring it closer to the goal of achieving a cure. In two key trials announced at the European Society for Medical Oncology meeting held in Berlin last weekend, Enhertu outperformed Roche's Kadcyla in preventing disease recurrence, and was more effective when used preoperatively.

This study is crucial for the six-year collaboration between AstraZeneca and Daiichi Sankyo. Their partnership has made Enhertu one of the fastest-growing cancer drugs globally, with sales reaching $3.75 billion last year. The drug was developed by Daiichi Sankyo, and AstraZeneca previously agreed to pay up to $6.9 billion for its co-development, marking AstraZeneca's largest deal in nearly a decade. This refers to the study of Enhertu used preoperatively.

Ken Keller, CEO of Daiichi Sankyo's U.S. division, stated, "Our goal is to cure patients, and that is the direction we have been striving for. What we understand is that Enhertu is set to become the cornerstone treatment for early-stage HER2-positive disease."

Enhertu is an antibody-drug conjugate—a treatment that can deliver chemotherapy directly to tumor cells while reducing damage to healthy tissue. These studies targeted HER2-positive breast cancer patients, who account for about one-fifth of all cases. According to AstraZeneca, approval for early-stage disease could allow the drug to benefit approximately 130,000 additional patients in the G7 countries.

In one study, over 92% of patients treated with Enhertu were alive and free of invasive disease three years after surgery, compared to 84% of patients treated with Kadcyla. The drug reduced the risk of death or recurrence by 53%. The incidence of severe side effects from Kadcyla was slightly higher, but Enhertu led to more cases of interstitial lung disease, a potentially serious condition involving inflammation and scarring of lung tissue.

Another study tested the drug preoperatively. Among patients treated with Enhertu, about two-thirds had no cancer cells remaining in their breast or lymph nodes at the time of surgery, compared to 56% in the standard treatment group. Patients treated with Enhertu also reported fewer severe side effects. Researchers noted that data on long-term recurrence-free survival is still immature but shows early positive trends.

At this conference, the biggest challenge for doctors was whether these study results mean Enhertu should be used preoperatively or postoperatively. For Sara A. Hurvitz, a medical oncologist at the Fred Hutchinson Cancer Center, she leans towards using the drug after surgery, following standard chemotherapy. She pointed out that there is currently no data indicating how long patients who received the drug preoperatively can survive without cancer recurrence Paul-Henri Cottu, an oncologist at the Curie Institute in Paris, did not participate in this research. However, he stated that he is "not very convinced" about the data related to the use of Enhertu before surgery and expressed uncertainty about whether this data is sufficient for approval. Nevertheless, he pointed out that the efficacy of Enhertu after surgery is clear.

Dave Fredrickson, Executive Vice President of Oncology at Astrazeneca, stated in an interview: "The data obtained from these two trials has 'significant advantages.' When discussing the question of at what early stage it is most appropriate to use Enhertu, this is an important topic that experts in the field need to explore in depth."