AstraZeneca and Daiichi Sankyo’s Enhertu Shows Superior Efficacy in Preventing Recurrence in Early-Stage HER2-Positive Breast Cancer

Intelligent Finance APP learned that Enhertu, the anticancer drug developed by AstraZeneca (AZN.US) and Japanese pharmaceutical company Daiichi Sankyo, has shown better treatment outcomes for early-stage breast cancer patients. These results could potentially allow this blockbuster drug to benefit more patients and bring it closer to achieving the goal of a cure. In two pivotal trials presented at the European Society for Medical Oncology meeting in Berlin last weekend, Enhertu outperformed Roche's Kadcyla in preventing disease recurrence and demonstrated superior efficacy when used prior to surgery.

The study is crucial to the six-year partnership between AstraZeneca and Daiichi Sankyo. Their collaboration 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 to co-develop it, marking the company's largest deal in nearly a decade. He was referring here to the research on the drug Enhertu before surgery.

Ken Keller, CEO of Daiichi Sankyo's U.S. division, said: "Our goal is to cure patients, and that's what we've been working towards. What we've come to understand is that Enhertu is set to become a cornerstone treatment for HER2-positive disease in its early stages."

Enhertu is an antibody-drug conjugate — a treatment that can deliver chemotherapy drugs directly to tumor cells while reducing damage to healthy tissues. These studies target patients with HER2-positive breast cancer, which accounts for about one-fifth of total cases. According to AstraZeneca, approval in earlier stages of the disease could allow the drug to benefit an additional approximately 130,000 patients in G8 countries.

In a study, more than 92% of patients treated with Enhertu were still alive and free of invasive disease three years after surgery, compared to 84% of those treated with Kadcyla. The drug reduced the risk of death or recurrence by 53%. Kadcyla had a slightly higher rate of severe side effects, 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 before surgery. About two-thirds of patients treated with Enhertu 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 said data on long-term recurrence-free survival is not yet mature but shows early positive trends.

At this conference, the biggest challenge for doctors lies in whether these research findings mean that Enhertu should be used before or after surgery. For medical oncologist Sara A. Hurvitz from the Fred Hutchinson Cancer Center, she tends to use the drug after surgery and following standard chemotherapy. She pointed out that there is currently no data showing how long patients who receive the drug before surgery can survive without cancer recurrence.

Paul-Henri Cottu, an oncologist at the Curie Institute in Paris, was not involved in this research. However, he stated that he is "not entirely convinced" by the data related to the use of Enhertu before surgery, and mentioned that he is unsure whether these data are sufficient for approval. Nevertheless, he pointed out that the efficacy of using Enhertu after surgery is clear.

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