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Results from key trials under way at Novavax, Inc. (NVAX -3.74%), Agile Therapeutics (AGRX 1.76%), and Karyopharm Therapeutics (KPTI -5.33%) should be available soon, and if those results are positive, then these three companies could have blockbuster drugs on the market soon. Can these companies overcome the odds and deliver a win for investors?

Targeting tens of millions of patients

Novavax is a clinical-stage company that's developing a vaccine against respiratory syncytial virus, or RSV, a common respiratory illness effecting the elderly and babies.

The company expects to report top-line data from its phase 3 study of its RSV-F vaccine prior to the end of this quarter, and if the vaccine is effective, then it could eventually be used to prevent RSV in millions of aging baby boomers.

Currently, RSV causes roughly 180,000 admissions to U.S. hospitals every year, including more than 57,000 hospital admissions for children. Preventing RSV is important because it can cause complications, including pneumonia and bronchiolitis, an infection of the small airways in the lungs.

If RSV-F is eventually approved, then Novavax believes its addressable market in the United States could exceed 100 million people in 2020. That has management thinking that peak annual sales for RSV-F could be north of $6 billion.

Improving birth control

Agile Therapeutics is a clinical-stage biotech that's developing next-generation contraceptive products for women. Twirla, a once-weekly contraceptive patch, is the company's lead product candidate and results from a phase 3 trial could be available before the end of 2016.

The company's management believes that the convenience of a once-weekly patch that potentially has fewer side effects than traditional oral contraceptives could help it capture meaningful share in what it estimates to be a $5 billion per year market.

Twirla's potential is intriguing, but investors should know that the FDA previously rejected Twirla after determining that the company's new drug application was insufficient for approval. After meeting with the FDA, the company designed its current phase 3 trial to address the FDA's concerns about patient tracking and compliance.

If management is correct in its assessment that Twirla's trial design will overcome the FDA's previous reservations, then this company could be significantly undervalued given that this could be a nine-figure drug. The company's market cap is currently only $211 million.

Addressing an important unmet need

Karyopharm Therapeutics is a clinical-stage company that's working on therapies for the treatment of hematological cancers, including multiple myeloma.

Specifically, selinexor is the company's lead drug candidate. Selinexor is being evaluated for use in multiple myeloma patients whose disease has progressed despite prior treatment. Although there have been several advances in treating multiple myeloma, most patients see their disease return and thus, patients will eventually exhaust the treatment options that are currently available.

Selinexor may provide newfound hope to these heavily pre-treated patients. In the past, response rates for patients who have already been treated with four different therapies have been in the 20% to 25% range. If combining selinexor with chemotherapy results in higher response rates than that, the FDA may consider accelerated approval.

Management plans to report top-line data from the phase 2b clinical trial this month, so we'll find out soon whether selinexor has a shot at reaching the market in 2017. If results are positive and the FDA approves selinexor, then sales of this drug could total in the hundreds of millions of dollars per year. For consideration, Revlimid, Velcade, and Pomalyst -- three commonly used multiple myeloma drugs -- are billion dollar blockbusters.

Overall, Karyopharm Therapeutics is a high risk/reward play, but it may be one worth buying.