Remdesivir, the Gilead Sciences (GILD) drug also known as "GS-5734," and originally developed as a treatment for Ebola, has been hailed as perhaps the best hope (currently under investigation) to help stop the spread of the SARS-CoV-2 coronavirus.Remdesivir is currently undergoing the fastest of fast-track authorizations to develop the drug and test its effectiveness against COVID-19. The most recent data on the drug's effectiveness, derived from an April 10 New England Journal of Medicine (NEJM) report and subsequent updates, suggests that the drug may have at least some efficacy in combating the novel coronavirus.To date, Gilead has made remdesivir available to about 1,800 patients globally. A variety of organizations are conducting formal clinical trials of the drug, the government of China and Gilead itself among them, and initial results from at least five such trials are expected to be arriving throughout April and May.Summarizing what we know so far, analyst Hartaj Singh of Oppenheimer notes that both China and Gilead are running separate Phase 3 clinical trials (two each), of the drug's effectiveness in treating "severe" and "moderate" cases of COVID-19, and at least some data from these trials may be available in just the "next few days."Meanwhile, the NEJM trial results, just published, show that 36 of 53 patients administered remdesivir in a "compassionate use" trial on severe COVID-19 patients showed clinical improvement to some extent, and more than half of those receiving the drug were ultimately able to have their oxygen tubes removed.So it sounds like progress is being made. Still, a few words of caution are in order."We view these results as purely directional," notes Singh, pointing out that the clinical trials under discussion are highly unorthodox in how quickly they are being conducted, and how many corners are being cut in the interests of getting results quickly. For one thing, "there was no control arm or natural history data to compare the efficacy" in the trial reviewed by NEJM for example. For another, this trial "was provided in the US, the EU, Canada, and Japan, likely with varying clinical protocols" depending on which medical system the patient was under the care of. Even the number of courses of treatment with the drug appears to be varying from trial to trial, which will make it difficult to ascertain precisely what dose of remdesivir is the right dose to administer in future uses. (To watch Singh's track record, click here)Other cautions should be more specifically taken to heart by potential investors in Gilead. Notably, Needham's Alan Carr mentions that the first 1.5 million vials of remdesivir are being made available "for free." Not only will Gilead make no money off these first doses. The company has almost certainly made substantial investments in developing this drug so quickly, and it may not make that money back anytime soon.In this regard, Carr notes that Gilead is only now "evaluating options for pricing strategy for subsequent batches if the drug is found to be helpful for COVID-19." While there's almost certainly going to be demand for the drug if it proves even moderately effective in combating COVID, there's no guarantee as to how profitable this product will be for Gilead — if it is even profitable at all.To this end, Carr reiterates a Hold rating on Gilead shares, without suggesting a price target. (To watch Carr's track record, click here)Overall, the jury is out on the drug giant. TipRanks reviewed 26 analysts and the results are divided. 13 are bullish on Gilead stock, 10 are sidelined and 3 are bearish. The consensus price target stands at $76.89, showing a modest 1% upside. (See Gilead stock analysis at TipRanks)To find good ideas for healthcare stocks trading at attractive valuations, visit TipRanks’ Best Stocks to Buy, a newly launched tool that unites all of TipRanks’ equity insights.