What happened

Shares of Exact Sciences Corporation (NASDAQ:EXAS) jumped as much as 12.9% on Thursday morning. The stock was up 6.3% as of 11:45 a.m. EDT. Exact Sciences continued to move higher after the stock's big gain on Wednesday following its announcement of a deal with Pfizer (NYSE:PFE) to co-promote DNA colorectal cancer test Cologuard.

So what

Investors are still digesting just how good the news of the Pfizer agreement is for Exact Sciences. And it should be really good news.

Cologuard packaging and materials

Image source: Exact Sciences.

After missing Wall Street analysts' revenue estimate in the second quarter, Exact Sciences' management team played up the fact that they would add more sales reps in the coming months. There's nothing like sales crews on-site to spread the word among physicians and healthcare systems.

Partnering with Pfizer could go a long way in making more physicians aware of -- and comfortable with -- Cologuard. Pfizer doesn't have a drug approved to treat colorectal cancer yet. However, the big drugmaker has a huge sales force and an established presence in the gastrointestinal space thanks to some of its other drugs. 

Exact Sciences said that Pfizer will augment its internal efforts in reaching out to physicians and healthcare systems. The company also stated that the big drugmaker will "actively participate in extending and deepening the Cologuard marketing campaign."   

Now what

Don't expect any impact from Exact Sciences' deal with Pfizer in the company's Q3 results. Pfizer won't begin co-promoting Cologuard until the fourth quarter. However, investors are likely to see the effects of the partnership with Pfizer when Exact Sciences reports its full-year and Q4 results in early 2019.

I continue to think that Exact Sciences' long-term prospects look quite good. Cologuard presents an attractive alternative for early colorectal cancer screening to patients who don't want to undergo a colonoscopy. The American Cancer Society's recommendation to lower the minimum age for colorectal cancer screening from 50 to 45 could pay off for Exact Sciences if insurers change their policies.

However, Exact Sciences will probably remain a very volatile stock with big moves both up and down. The stock's valuation is based on expectations of tremendous growth. That means Exact Sciences must meet these expectations or see the stock fall hard. While I like the stock, it's only suitable for highly aggressive investors.