Value stocks are almost always a worthwhile addition to a well-rounded portfolio. Under-the-radar stocks trading at discounted valuations, after all, generally perform well in any type of market. That said, it's not necessarily easy to differentiate between a stock that's truly undervalued, and those that are trading at low multiples of earnings, cash flow, or book value for one or more fundamental reasons.  

Which stocks make the grade as tried and true value plays right now? The healthcare stocks Clovis Oncology (NASDAQ:CLVS)Cresco Labs (OTC:CRLBF), and Sarepta Therapeutics (NASDAQ:SRPT) are three top-shelf names that are currently trading at absurdly low valuations, despite their promising long-term outlooks. Here's why bargain hunters may want to pounce on these three deeply undervalued healthcare stocks soon. 

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Image source: Getty Images.

Clovis: Don't sleep on this rebound

Clovis, a small-cap cancer specialist, has lost a staggering 83% of its value since the Food and Drug Administration (FDA) originally approved the PARP inhibitor, Rubraca, as a treatment for advanced ovarian cancer. The reason is that Rubraca has been unable to adequately compete against rival therapies from pharma heavyweights AstraZeneca and GlaxoSmithKline. Making matters worse, Clovis has also burned through cash at a dizzying rate during this period.

Clovis' shares, however, have perked up in a big way ever since the company's Q3 earnings release earlier this month. The drugmaker's shares have jumped by 31% over the last two weeks thanks to the growing optimism about Rubraca's future, as well as the company's ability to significantly curtail net losses over its latest quarter. The big-ticket item, if you will, is the potential for Rubraca to break into BRCA-mutant advanced prostate cancer, perhaps as soon as late 2020. 

What does this all mean? Clovis' market cap currently stands at $425 million, but Rubraca's sales could climb into the $700 million range with a label expansion that includes advanced prostate cancer. As most cancer companies trade at no less than three times the peak sales of their flagship medicine, it's easy to see why Clovis' shares are starting to heat up.  

Cresco Labs: A future giant of the cannabis space

Although valuations across the nascent cannabis space have taken a major step backward this year, the long-term promise of the industry remains completely intact. Eventually, the U.S. will shelve its 82-year long prohibition on marijuana, whereby opening the door wide open to a $100 billion market place.  

Which pot companies are in the best position to take advantage of this watershed event? While investors have been busy looking to our northern neighbor for entry points into this high-value space, there's a strong case to be made that American's own Cresco Labs -- a Chicago-based multistate cannabis operator -- may, in fact, be the best play overall.

The lowdown is that Cresco is set to acquire Origin House (OTC:ORHOF), which is one of the largest holders of cannabis distribution licenses in the all-important state of California. 

If this deal does indeed go through -- and it appears that it will -- Cresco will sport a monstrous commercial footprint spanning 11 states and should end up grabbing the lion's share of the massive California cannabis market as well. At the end of prohibition, Cresco would thus be in the catbird seat in the U.S. market. That's a doozy of a value proposition, given the enormous size of the U.S. cannabis market and Cresco's tiny market cap.   

Sarepta: Denied but not out

Sarepta's shares are down by 33.6% from their 52-week highs all due to the surprise rejection of the company's next Duchenne muscular dystrophy drug (DMD) Vyondys 53 last August by the FDA. This rejection sparked unfounded fears in the investing community that the FDA has an ax to grind against Sarepta over the controversial approval of the company's DMD therapy Exondys 51. As Sarepta CEO Doug Ingram put it, the company has been "treated very fairly and professionally by the Division of Neurology." 

That being said, there is a distinct possibility that Sarepta's exon-skipping DMD therapies may have hit their high-water mark from a regulatory and commercial standpoint. But that doesn't mean investors should throw in the towel on this company.

Sarepta is currently working on an impressive micro-dystrophin boosting gene therapy for DMD that could prove to be a game changer -- along with a host of other gene therapies indicated for several additional orphan diseases. Moreover, Sarepta is still the only company to have ever brought a therapy to market for DMD -- and it might remain that way for a while longer, depending on the regulatory outcome for NS Pharma's Viltolarsen. 

The long and short of it is that the sentiment around this beaten-down biopharma should change within the next few months due to its unique gene therapy platform. So, investors may want to grab some shares while the stock remains well off its 52-week highs.