Big pharmas like AstraZeneca (AZN -1.82%) rise and fall based on how much money they can earn from their medicines on the market. With regulators at the European Medicines Agency (EMA) now giving the company a green light for three of its medicines in the last month, shareholders are likely to be salivating in anticipation of the future sales. 

Now, only the final stamp of approval from the European Commission (EC) for marketing authorization awaits before sales can proceed. It's obligated to give a ruling within 67 days of the EMA's findings, so a triad of commercialization efforts are probably right around the corner. But do the three medicines have any hope of moving the needle for a business as large as AstraZeneca, and if so, does that mean they're valid reasons to buy the company's stock?

Money is already starting to roll in

The trio of medicines that the EMA recommended for approval for their initial or expanded indications are called Tezspire, Ultomiris, and Enhertu.

Tezspire is a biologic therapy for severe asthma that's still problematic after treatment with corticosteroids in addition to another drug.​​ It was already approved in the U.S. late last year, but it only made $3 million in gross profit for the company in the first quarter, partially because it split the proceeds in the U.S. with its development partner, Amgen.

Sales will probably ramp up over time, especially with the addition of the EU market, though it's unclear how much management is expecting at the peak. It's also being investigated for a slew of other indications, so its contribution to AstraZeneca's growth is likely just beginning. 

The second drug advanced for approval, Ultomiris, is intended to be an adjunct treatment for certain subsets of patients with generalized myasthenia gravis (gMG) -- a chronic disease of the skeletal muscles. It could soon become the only long-acting drug on the EU market for that population, giving it the potential to capture a massive market share.

However, the fact that Ultomiris is an add-on rather than a first-line therapy means that its total addressable market is likely to be on the smaller side. And as it only targets a portion of this patient population, that constrains its addressable market size still further. The bright side is that the drug is already approved for several other indications, and it brought in $419 million globally in Q1. Therefore, any additional revenue that the company can make from it is icing on the cake.

Finally, Enhertu is an antibody-drug conjugate (ADC) targeted to patients with unresectable HER2-positive breast cancer who have already been treated with another HER2-targeted medicine. Breast cancer is the most prevalent form of cancer, and around 20% of patients are HER2-positive.

Furthermore, the therapy is already approved in a handful of global markets, and it yielded $75 million in gross profits from sales during the first three months of 2021. AstraZeneca is also investigating Enhertu for a few other cancers, like colorectal cancer and lung cancer, so this approval may not be the last. And if its recent performance is anything to go by, it'll be a strong seller in the EU.

Keeping things in context

As positive as these three new approvals are for the company, they are unlikely to constitute good reasons to buy shares of AstraZeneca on their own. AstraZeneca's trailing 12-month revenue is nearly $41.5 billion, and this year management expects to grow its top line by a percent figure in the high teens. Increasing sales of Ultomiris, Enhertu, and Tezspire are doubtlessly part of that calculation, but -- at least for now -- they might not bring in enough to make the annual sum budge by much. 

Nonetheless, the sheer scale of AstraZeneca's pipeline and its products on the market mean that it's likely to continue being a strong competitor within the biopharma sector for years to come. Right now, the drugmaker has at least 183 programs in its pipeline, 16 of which are in late-stage development. This means it could still be worth adding to your portfolio, provided that you're more interested in a steadily expanding behemoth than a fast-rising growth stock.