This week, pharma and biotech giant AstraZeneca (NASDAQ: AZN) cleared its final hurdle in the proposed acquisition of orphan drug pharma company Alexion Pharmaceuticals (NASDAQ: ALXN) when it announced that the deal had received clearance from the United Kingdom's Competition and Markets Authority (CMA) on July 14. The $39 billion acquisition, which was announced last December and unanimously approved by boards of directors at both AstraZeneca and Alexion Pharmaceuticals -- as well as overwhelmingly supported by shareholders of both companies -- will "create a leader in immunology and precision medicines," as AstraZeneca CFO Marc Dunoyer put it in May. Image Source: Getty Images. As a result of preceding approvals from regulatory bodies (i.e., the European Commission's clearance earlier this month and clearance from the U.S. Federal Trade Commission in April), AstraZeneca expects its acquisition of Alexion Pharmaceuticals to close on July 21. AstraZeneca is on the verge of dominating the market for rare disorders AstraZeneca's decision to acquire Alexion Pharmaceuticals looks promising. Dunoyer lauded Alexion Pharmaceuticals as "a pioneer in the discovery and development of medicines for rare diseases," and it's safe to assume that AstraZeneca's move was prompted by market research such as that produced by firm Insight Slice, which is forecasting a 10% compound annual growth rate in the global orphan drug market from an estimated $148 billion in 2019 to $413 billion by 2030. AstraZeneca's notable orphan drug blockbusters (including non-small cell lung cancer drugs Tagrisso and Imfinzi and pancreatic cancer drug Lynparza) brought in more than $8 billion in combined 2020 sales, making up about 5% of the estimated $163 billion in 2020 global orphan drug revenue. Once the deal to acquire Alexion Pharmaceuticals closes, the company's orphan drug portfolio will be boosted by the additions of key drugs including Soliris, Ultomiris, and Strensiq, which combined generated about $6 billion in revenue for Alexion Pharmaceuticals in 2020. When the deal closes, the combined company's 2020 orphan drug market share would be boosted from 5% to 9% -- and that's not even considering Alexion Pharmaceuticals' robust orphan drug pipeline. If we factor in even a very slight increase in AstraZeneca's orphan drug market share -- say, from 9% in 2020 to 10% in 2030 -- the massive growth of the market that is expected to occur over that time brings us astounding results: AstraZeneca's orphan drug revenue would triple from $14 billion in 2020 to $41 billion by 2030. An exciting opportunity now Given that AstraZeneca's total 2020 revenue, independent of Alexion Pharmaceuticals, was $27 billion, the orphan drug market alone will likely be enough to meaningfully contribute to the company's top and bottom-line growth over the next decade. Using this rationale, I believe that AstraZeneca is a good buy under $60 for investors who are seeking the potential for significant capital appreciation by 2030 -- and the market-beating 2.4% dividend yield is a nice bonus in the meantime. 10 stocks we like better than AstraZenecaWhen our award-winning analyst team has a stock tip, it can pay to listen. After all, the newsletter they have run for over a decade, Motley Fool Stock Advisor, has tripled the market.* They just revealed what they believe are the ten best stocks for investors to buy right now... and Alexion Pharmaceuticals wasn't one of them! That's right -- they think these 10 stocks are even better buys. See the 10 stocks *Stock Advisor returns as of June 7, 2021 Kody Kester has no position in any of the stocks mentioned. The Motley Fool has no position in any of the stocks mentioned. The Motley Fool has a disclosure policy.Source