Berkshire Hathaway (NYSE: BRK.A)(NYSE: BRK.B) CEO Warren Buffett is widely considered to be the greatest investor to ever walk the planet. His unparalleled investing acumen transformed early Berkshire Hathaway shareholders into multi-millionaires many times over. Buffett's core strategy boils down to spotting underappreciated businesses that sport well-established competitive advantages over their peers, and then letting time do the heavy lifting. This tried-and-true value investing strategy has made Buffett a staggering $90.2 billion in net worth, a figure that doesn't include his generous donations to various charities such as the Bill and Melinda Gates Foundation. Not all of Buffett's stock picks have panned out, however. What's more, the Oracle of Omaha has also, on more than one occasion, bought companies without a clear-cut competitive moat, or even decent near-term growth prospects. Berkshire Hathaway's deep dive into the pharmaceutical space with the purchase of biotech heavyweight Biogen Inc. (NASDAQ: BIIB) toward the tail end of 2019 and its sizable stake in struggling generic drug king Teva Pharmaceutical Industries Ltd. (NYSE: TEVA) back in 2017 are two prime examples. Are these head-scratching stock picks actually worthwhile contrarian buys? Let's break down the near-term outlook of each of these pharma titans to find out. Image source: Getty Images. Biogen: A leap of faith Biogen has undoubtedly been an outstanding long-term buy and hold for investors. In fact, the biotech's shares have made some of its early-bird investors a cool million dollars. Biogen's future, however, is extremely murky. The company's growth engine consists of its broad multiple sclerosis (MS) franchise, as well as the rare disease drug, Spinraza, indicated for patients with spinal muscular atrophy. Unfortunately, the biotech's MS franchise faces an onslaught of novel competitive threats, and Spinraza's days as a key growth driver appear to be at an end. To overcome these hurdles, Biogen's management is betting the house on a controversial Alzheimer's disease drug candidate known as aducanumab. If approved, this drug may quickly rack up some truly mind-boggling sales. The problem is that there is only a razor-thin chance that the Food and Drug Administration will actually approve it. Aducanumab, after all, wasn't an outright success in its late-stage clinical program. Moreover, a host of highly similar drugs flat out failed in their respective pivotal trials. Adding yet another layer of risk is the fact that management hasn't tackled its near-term growth problem -- or the sky-high regulatory risk associated with aducanumab -- through a bolt-on acquisition. In all, Berkshire Hathaway's decision to buy Biogen ahead of this make-or-break regulatory decision is curious indeed. The holding company has never shown much appetite for risk in the past. Yet, there's a real chance that this large-cap biotech stock could absolutely plummet in the more-than-likely event that aducanumab turns into a dead end. So, unless you are a risk-tolerant investor, you might want to avoid Buffett's latest pure-play pharmaceutical stock. Teva: A slow motion turnaround play Berkshire Hathaway first bought this generic drug king in late 2017. At that time, it seemed that newly minted CEO Kare Schultz could effect a quick turnaround after a disastrous series of events that drove the drugmaker to the brink of bankruptcy. Long story short, Teva's former brain trust had grossly overpaid for Allergan's generic drug business in a move designed to offset the eventual decline of the MS medicine Copaxone. This ill-fated business development activity, in turn, straddled Teva with a boatload of debt and hamstrung its deal-making capacity. As Schultz's appointment hasn't been the panacea for the drugmaker's various problems that many envisioned back in 2017, Teva's stock has gone on to lose a jaw-dropping 25% of its value during his tenure. What's more, Teva's top line still isn't headed in the right direction over two years later -- despite the healthy sales growth for a handful of newer products like Austedo and Ajovy in recent quarters. As a result, Teva's shares have consistently been one of the cheapest healthcare stocks pretty much since Berkshire Hathaway first bought it. Are better days ahead? The good news is that Teva has been steadily deleveraging and building out a strong portfolio of growth-oriented products. Investors, in kind, have subsequently bid up this beaten-down pharma stock by a noteworthy 34% so far in 2020. This return to form should continue to round into shape this year, fueled by the drugmaker's cost-cutting efforts and new drug launches. That being said, Berkshire probably has a long way to go before realizing even a modest gain on this pharma stock. Lay investors, therefore, should clearly think twice before trying to simply piggyback off of Buffett's stock picks -- especially in the area of biopharma, an industry that has never been particularly kind to the Oracle of Omaha. 10 stocks we like better than Berkshire Hathaway (A shares)When investing geniuses David and Tom Gardner have a stock tip, it can pay to listen. After all, the newsletter they have run for over a decade, Motley Fool Stock Advisor, has tripled the market.* David and Tom just revealed what they believe are the ten best stocks for investors to buy right now... and Berkshire Hathaway (A shares) wasn't one of them! That's right -- they think these 10 stocks are even better buys. See the 10 stocks *Stock Advisor returns as of December 1, 2019 George Budwell has no position in any of the stocks mentioned. The Motley Fool owns shares of and recommends Berkshire Hathaway (B shares) and Biogen and recommends the following options: long January 2021 $200 calls on Berkshire Hathaway (B shares), short January 2021 $200 puts on Berkshire Hathaway (B shares), and short March 2020 $225 calls on Berkshire Hathaway (B shares). The Motley Fool has a disclosure policy.Source