Is Esperion Therapeutics, Inc. overvalued or undervalued?

As of 8 May 2019, the valuation grade for Esperion Therapeutics, Inc. moved from does not qualify to risky, indicating a shift in perception regarding its financial health. The company is considered overvalued given its negative P/E ratio, a price to book value of -0.57, and an EV to EBITDA ratio of -18.10. In comparison, Protalix Biotherapeutics, Inc. has a P/E of 20.08, highlighting a stark contrast in valuation metrics among peers.
Despite a notable 1-month stock return of 30.95%, which outperformed the S&P 500's 2.33% return, the long-term performance is concerning, with a 5-year return of -92.98% compared to the S&P 500's 96.61%. This suggests that while there may be short-term gains, the overall outlook for Esperion remains bleak, reinforcing the conclusion that the stock is overvalued.