Introduction
As Japanese pharmaceutical companies continue to deliver solid business results, blockbuster drugs with annual sales exceeding ¥100 billion are becoming increasingly prominent. Daiichi Sankyo’s cancer drug Enhertu, Eisai’s early Alzheimer’s disease treatment Leqembi, Takeda Pharmaceutical’s Entyvio, and Astellas Pharma’s Xtandi are all core products that significantly support each company’s sales. At the same time, while such large-scale drugs can serve as engines of corporate growth, they also carry the risk of causing major fluctuations in earnings due to patent expirations and intensifying competition. This news highlights the challenge facing Japanese pharmaceutical companies: how to use blockbuster drugs to grow in the global market, and how to develop the next sources of growth.
Blockbuster Drugs Can Rapidly Drive Corporate Growth
What stands out most in this news is the presence of Daiichi Sankyo’s Enhertu. Its sales in fiscal 2025 reached ¥698.4 billion, accounting for roughly one-third of the company’s total revenue. For a pharmaceutical company, having a single product become such a large source of earnings is extremely significant in accelerating research and development investment and overseas expansion.
Enhertu is a successful example of a new treatment approach known as an antibody-drug conjugate, or ADC. Oncology is a highly competitive field in which major global pharmaceutical companies are also investing heavily, but Daiichi Sankyo has quickly increased its presence in this area. This is not simply a story about one drug selling well. The important point is that having a new technological platform can create opportunities for the development of follow-on products and broader partnership strategies.
The Value of Drugs That Create New Markets
Eisai’s Leqembi is also noteworthy, although in a slightly different sense from a typical blockbuster drug. Leqembi is a treatment for early Alzheimer’s disease, and it is a product that seeks to create a new market in a field where treatment options have traditionally been limited. Its sales in fiscal 2025 were ¥88.0 billion, and they are expected to grow to ¥143.5 billion in fiscal 2026.
In particular, the subcutaneous formulation Leqembi Iqlik could have a major impact on future adoption. In Alzheimer’s disease treatment, not only efficacy but also ease of use for patients and medical institutions is important. If treatment options expand from intravenous infusion to subcutaneous injection, the barriers to starting treatment may be lowered, potentially leading to market expansion.
In this respect, Leqembi is not merely a story of sales growth. It is becoming a competition over a business model that includes multiple factors, such as ease of introduction in clinical practice, diagnostic systems, and patient access.
The Higher the Dependence, the Greater the Patent Expiration Risk
On the other hand, blockbuster drugs also involve clear risks. The more a large-scale drug supports a company’s sales, the greater the impact of patent expiration or the emergence of competing products. Astellas Pharma’s Xtandi recorded sales of ¥960.8 billion in fiscal 2025 and supported the company’s record-high revenue. However, the more dependent a company is on a particular product, the more important it becomes to prepare for future declines in earnings.
This challenge also applies to Daiichi Sankyo. Precisely because Enhertu has grown rapidly, the company needs to accelerate the development of follow-on ADCs and advance a growth strategy that looks beyond patent expiration. Blockbuster drugs strengthen companies, but they can also become a source of weakness. The key question is whether a company can avoid continuing to depend on a successful drug and instead channel the profits from that drug into the creation of the next new medicines.
The Strength of Mature Products Seen in Takeda and Astellas
Takeda Pharmaceutical’s overall revenue declined slightly year on year, but Entyvio generated ¥958.0 billion in sales, allowing the company to maintain the top position in sales among Japanese pharmaceutical companies. This demonstrates the strong earnings power of core products, something that may not be fully visible from the company’s overall growth rate alone.
Astellas Pharma is also seeing growth in five key strategic products, including Padcev, in addition to Xtandi. This point is important. Having a mainstay product is itself a strength, but a company’s future outlook changes significantly depending on whether it can develop multiple growth products around that mainstay. If a company can shift from dependence on a single product to growth driven by multiple products, it can diversify patent expiration risk to some extent.
The Growth Cycle Required of Japanese Pharmaceutical Companies
The central issue revealed by this news is whether blockbuster drugs can be turned from temporary successes into a sustainable growth cycle. If the profits generated by large-scale drugs can be invested in research and development, licensing, and the strengthening of overseas sales networks, and if those investments can nurture the next new drugs, corporate value will continue to rise.
Conversely, if a company relies too heavily on the sales of its core products and falls behind in developing its next pillars, its growth potential may decline rapidly when patents expire. For pharmaceutical companies, blockbuster drugs are not the final goal. They are a source of funds for the next stage of growth and a means of buying time.
Conclusion
Japanese pharmaceutical companies are beginning to create products that can compete effectively in the global market. Daiichi Sankyo’s Enhertu has established a global presence in the ADC field, while Eisai’s Leqembi is seeking to expand a new market in Alzheimer’s disease treatment. Takeda Pharmaceutical and Astellas Pharma are also maintaining their earnings bases around their core products.
However, the true strength of a pharmaceutical company cannot be measured solely by whether it has one major drug. What matters is whether the company can use the profits generated by that large-scale drug to create the next drug, the next market, and the next foundation for growth. Blockbuster drugs can be a powerful trump card that propels a company forward, but if a company becomes too dependent on them, they can also become a future risk. For Japanese pharmaceutical companies to grow further, they must not become complacent with successful products. Instead, they need to create a virtuous cycle of new drug development starting from their blockbuster drugs.