Biotechs like CRISPR Therapeutics (CRSP -2.56%) can be tricky to invest in, as it isn't always obvious whether management's plans are working or not. Simply focusing on a big-picture figure like revenue often misses key points about what the company has done and where it's going.

On that note, CRISPR's Q3 earnings will be reported sometime between Nov. 4 and Nov. 8 at the latest. When those results come out, investors should pay particular attention to two all-important numbers that will determine how it performs in the near term and beyond. Let's take a beat to understand both so that you'll get a clearer signal of whether buying this stock is the right move or not.

Building out treatment infrastructure is necessary for revenue growth

As you may have heard, CRISPR recently got approval for its first product, a gene therapy called Casgevy, which treats sickle cell disease (SCD) as well as beta-thalassemia. In the long run, with some additional research and development (R&D) investment to increase the size of the therapy's addressable market, management calculates that upwards of 166,000 patients in the U.S. and E.U. could be eligible for treatment.

It's fairly straightforward to appreciate that the number of patients actually treated is a very important figure to keep track of from an investment standpoint. Without treating patients, there's no way to realize revenue from sales of the medicine.

At the time of its Q2 earnings release, CRISPR had started treatment of just 20 patients, so it had no revenue to speak of. But Casgevy isn't a medicine that's simple to manufacture. Patients need to donate their own cells, undergo a chemical conditioning regimen, and wait for the company to modify their cells at an external manufacturing site before they can receive the treatment.

The process takes weeks and may also be burdensome to prospective patients, as it involves a hospital stay. Seeing some social proof in the form of a population of patients who have successfully been treated may help to convince others to take the plunge, which is why the pace of treating new patients is worth paying attention to.

Furthermore, the touchpoints that involve the patient have to occur at authorized treatment centers (ATCs) set up by the company and its collaborator, Vertex Pharmaceuticals. As of the second quarter's close, there were 35 operational ATCs. By the end of 2024, it aims to have 50 ATCs up and running in the U.S. and 25 in the E.U. And that's just one reason why the number of ATCs relative to management's goal is another key number to watch.

If ATCs aren't attracting enough patients to start treatment on average, it'll represent a poor return on CRISPR's investments in setting them up and operating them.

Profitability will probably take a while longer

Today, Casgevy's rollout is just getting started.

On average, Wall Street analysts don't see the therapy bringing in enough revenue relative to its costs to make CRISPR profitable this year or even in 2025. Onboarding more new patients than anticipated, perhaps by spinning up ATCs faster than expected, could change that calculation to the benefit of shareholders -- or, in the reverse case, make it worse. Thus far, it looks like management's goal for the number of ATCs launched in 2024 could break in either direction, which is why the third-quarter earnings report is so important.

Still, prospective investors should remember that these issues are more likely to loom larger in the near term than they will over the long term, assuming there is no big disconnect between Casgevy and its target markets. The veracity of that assumption is in the process of being clarified. As there's more data on new patient starts and the economic efficiency of ATCs, it'll become clearer whether CRISPR's first medicine is a star or a flashy underperformer.

The balance of evidence right now suggests that while Casgevy might not ever become a blockbuster drug, it will indeed provide sufficient cash flows to launch CRISPR's life as a self-sustaining biotech company that doesn't need handouts from collaborators or shareholders to stay financially stable. The longer an investor waits, the more clarity there will be on that point, but the upside will be somewhat reduced as risks scale down.

If you're comfortable with that, it's ready for an investment today -- but it's probably worth seeing those two key figures in the next earnings update to be confident that things are proceeding according to plan.