The healthcare sector has been crushing it for the better part of the last decade, thanks to a boon in innovation, widespread merger and acquisition activity, an aging global population that's been driving a surge in demand for healthcare products of all kinds, and the legitimization of the medical marijuana industry in numerous geographies across the globe. Best of all, Wall Street and industry insiders alike expect this powerful growth trend to remain vibrant for at least another decade -- making now a great time to stash a few healthcare stocks away for the long haul.

Which healthcare stocks are the best growth vehicles? Although there are arguably several decent candidates, the pot titan Aphria (APHA) and the orphan-drug specialist Retrophin (TVTX -1.88%) are both poised for monstrous gains in the coming decade. Here's what you need to know about these two healthcare growth stocks right now.  

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A rare value play in marijuana

Most marijuana stocks have been in beast mode over the last two years in response to the legalization of adult-use recreational pot in Canada and the emergence of more friendly laws toward the use of marijuana for medical purposes in literally dozens of countries. This so-called "green rush," however, has caused valuations across the industry to reach unsavory levels. 

There is one exception to this general rule of thumb: the Ontario-based pot titan Aphria. Unlike most Canadian cannabis stocks, Aphria's shares have essentially traded sideways over the last 12 months. The net result is that Aphria's stock is only trading at 3.2 times its projected 2020 sales. To put this valuation estimate into the proper context, the average forward-looking price-to-sales ratio among the top players in the industry presently stands at around 16. Aphria is therefore a bargain by comparison.

The catch, though, is that Aphria's shares have lagged behind the top dogs for a number of very good reasons. First off, some of the company's former brass were accused of double dealing in a report by short-sellers late last year, leading to a change in leadership. The company has also had to fight off a hostile takeover bid and start the long process of rebuilding its image with the investing community. 

On the plus side, Aphria still has the third-largest production capacity among Canadian growers at 255,000 kgs per year. So, if the company can get its proverbial house in order, it should eventually rebound in a big way. As a top-tier producer, after all, Aphria is well positioned to take advantage of the industry's monstrous growth rate over the next decade.  

Retrophin: Catalysts inbound

Retrophin presently markets three drugs: Chenodal, Cholbam, and Thiola. However, the company's most important value drivers are its late-stage clinical candidates fosmetpantotenate and sparsentan. 

Fosmetpantotenate is barreling toward a late-stage readout as a treatment for pantothenate kinase-associated neurodegeneration -- or PKAN for short -- in the third quarter of this year. PKAN is a deadly neurodegenerative disorder that reportedly afflicts around 5,000 individuals worldwide. While this is an ultra-small market, fosmetpantotenate stands to be the first drug specifically indicated for PKAN. Fosmetpantotenate should also garner a premium pricing structure due to PKAN's market size, giving the drug significant commercial potential.

Sparsentan -- a drug licensed from Ligand Pharmaceuticals and Bristol-Myers Squibb -- is currently being assessed in two pivotal trials for the rare kidney ailments known as focal segmental glomerulosclerosis (FSGS) and immunoglobulin A nephropathy (IgAN). The drug's top-line FSGS data are expected to be released toward the back half of 2020 and its IgAN trial data are scheduled for public consumption in the first half of 2022. Taken together, these two orphan indications have the potential to transform sparsentan into a tremendous growth driver for the company for years to come. 

What's the big deal? Retrophin's top line could grow at an exponential rate over the next five years if both fosmetpantotenate and sparsentan pan out. In fact, EvaluatePharma expects the company to evolve into one of the fastest-growing players in the orphan drug space due to these two late-stage clinical candidates. So, even though the threat of a clinical setback is a serious risk with this biotech, Retrophin's shares also have the very real potential to double or perhaps triple in value if all the stars align. This biotech's intriguing risk to reward should thus appeal to aggressive investors on the hunt for unusual growth opportunities.