Sifting through countless of stocks in the Biotechnology industry can be tedious, and sometimes two stocks are just too similar to judge which is the better investment. If you’re on the fence about investing in Protagonist Therapeutics, Inc. or Alkermes plc because you’re not sure how they measure up, it’s important to compare them on a few factors before making your decision.

Read on to learn how Protagonist Therapeutics, Inc. and Alkermes plc compare based on key financial metrics to determine which better meets your investment needs.

About Protagonist Therapeutics, Inc. and Alkermes plc

Protagonist Therapeutics, Inc. operates as a discovery and development company in the United States. It develops Icotyde, a first-in-class investigational targeted oral peptide for the treatment of adults and pediatric patients 12 years of age and older with moderate-to-severe plaque psoriasis; and Rusfertide, a first-in-class investigational injectable mimetic of the natural hormone hepcidin in Phase 3 development for the treatment of the rare blood disorder polycythemia vera. The company is also developing PN-881, a potential best-in-class oral peptide IL-17 antagonist, for the treatment of immune-mediated skin diseases in Phase 1 clinical trials; PN-477 and PN-458, which are development candidates for the treatment of obesity; PN-8047, an orally administered hepcidin functional mimetic small molecule; L-4R alpha antagonist for the treatment of atopic dermatitis and moderate-to-severe asthma; and amylinR-based oral and subcutaneous mono- and poly-agonists for the treatment of obesity. Protagonist Therapeutics, Inc. was incorporated in 2006 and is headquartered in Newark, California.

Alkermes plc, a biopharmaceutical company, engages in the research, development, and commercialization of pharmaceutical products to address unmet medical needs of patients in therapeutic areas in the United States, Ireland, and internationally. The company has a portfolio of proprietary commercial products for the treatment of opioid dependence, alcohol dependence, schizophrenia, bipolar I, and a pipeline of clinical and preclinical product candidates in development for neurological disorders. Its marketed products include ARISTADA, an intramuscular injectable suspension for the treatment of schizophrenia; ARISTADA INITIO for the treatment of schizophrenia in adults; VIVITROL for the treatment of alcohol and prevention of opioid dependence; LYBALVI, an oral atypical antipsychotic drug candidate for the treatment of adults with schizophrenia and bipolar I disorder; and LUMRYZ, an extended-release oral suspension product for the treatment of cataplexy or EDS in pediatric patients. The company also offers proprietary technology platforms to third parties to enable them to develop, commercialize, and manufacture products. It has collaboration agreements primarily with Janssen Pharmaceutica N.V., Janssen Pharmaceutica Inc, and Janssen Pharmaceutica International. Alkermes plc was founded in 1987 and is headquartered in Dublin, Ireland.

Latest Biotechnology and Protagonist Therapeutics, Inc., Alkermes plc Stock News

As of July 30, 2026, Protagonist Therapeutics, Inc. had a $8.9 billion market capitalization, compared to the Biotechnology median of $251.9 million. Protagonist Therapeutics, Inc.’s stock is up 56.4% in 2026, up 0.4% in the previous five trading days and up 152.37% in the past year.

Currently, Protagonist Therapeutics, Inc. does not have a price-earnings ratio. Protagonist Therapeutics, Inc.’s trailing 12-month revenue is $74.1 million with a -154.9% net profit margin. Year-over-year quarterly sales growth most recently was 99.3%. Analysts expect adjusted earnings to reach $4.467 per share for the current fiscal year. Protagonist Therapeutics, Inc. does not currently pay a dividend.

As of July 30, 2026, Alkermes plc had a $8.4 billion market cap, putting it in the 75th percentile of all stocks. Alkermes plc’s stock is up 75.1% in 2026, down 7.4% in the previous five trading days and up 85.3% in the past year.

Currently, Alkermes plc’s price-earnings ratio is 128.9. Alkermes plc’s trailing 12-month revenue is $1.7 billion with a 4.0% net profit margin. Year-over-year quarterly sales growth most recently was 27.0%. Analysts expect adjusted earnings to reach $1.275 per share for the current fiscal year. Alkermes plc does not currently pay a dividend.

How We Compare Protagonist Therapeutics, Inc. and Alkermes plc Stock Grades

Stock evaluation requires access to huge amounts of data and the knowledge and time to sift through it all, make sense of financial ratios, read income statements and analyze recent stock movements. AAII created A+ Investor, a robust data suite that condenses data research in an actionable and customizable way suitable for investors of all knowledge levels, to help investors streamline and work through such data.

AAII’s proprietary stock grades come with A+ Investor. These offer intuitive A‐F grades for each of five key investing factors: value, growth, momentum, earnings estimate revisions and quality. Here, we’ll take a closer look at Protagonist Therapeutics, Inc. and Alkermes plc’s stock grades to see how they measure up against one another.

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Protagonist Therapeutics, Inc. and Alkermes plc’s Quality Grades

Company	Ticker	Quality
Protagonist Therapeutics, Inc.	PTGX	D
Alkermes plc	ALKS	C

Like the Value Grade, AAII’s A+ Investor Quality Grade comes from the percentile rank of key metrics. Specifically, the Quality Score is the percentile rank of the average of the percentile ranks of return on assets (ROA), return on invested capital (ROIC), gross profit relative to assets, buyback yield, change in total liabilities to assets, accruals, Z double prime bankruptcy risk (Z) score and the F-Score.

The score is variable, meaning it can consider all eight measures or, should any of the eight measures not be valid, the remaining measures that are valid. To be assigned a Quality Score, stocks must have a valid (non-null) measure and corresponding ranking for at least four of the eight quality measures.

The Quality Score is used to assess the underlying “quality” of a particular stock. A higher-quality stock possesses traits associated with upside potential and reduced downside risk. Backtesting of the Quality Grade shows that stocks with higher grades, on average, outperformed stocks with lower grades over the period of 1998 through 2019.

Stocks receive better grades (higher scores) for having higher scores for the quality subcomponents and worse grades (lower scores) for lower scores for the subcomponents.

Protagonist Therapeutics, Inc. has a Quality Score of 38, which is Weak. Alkermes plc has a Quality Score of 46, which is Average.

The Quality Stock Winner: No Clear Winner

Neither Protagonist Therapeutics, Inc. or Alkermes plc has a high enough Quality Grade to be considered a “winner.” Investors who are considering these companies should do additional due diligence and research to see if either could be a good addition to their portfolios. It’s important to look at a wide range of financial metrics in order to determine if Protagonist Therapeutics, Inc. or Alkermes plc is the better investment when it comes to quality.

Protagonist Therapeutics, Inc. and Alkermes plc’s Momentum Grades

Company	Ticker	Momentum
Protagonist Therapeutics, Inc.	PTGX	A
Alkermes plc	ALKS	A

Momentum grades help to uncover stocks experiencing anomalously high rates of return; research finds that stocks with high relative levels of momentum tend to outperform, whereas those with low levels of momentum tend to continue underperforming. Momentum is based on the price change of a stock over a specified period relative to all other stocks.

Typically, AAII looks at the weighted relative strength over the trailing four quarters. The weighted four-quarter relative strength rank is the relative price change for each of the past four quarters. The most recent quarterly price change is given a weight of 40% and each of the three previous quarters are given a weighting of 20%.

Protagonist Therapeutics, Inc. has a Momentum Score of 94, which is Very Strong. Alkermes plc has a Momentum Score of 91, which is Very Strong.

The Momentum Grade Winner: It’s a Tie!

Looking at the Momentum Grade breakdown above, both Protagonist Therapeutics, Inc. and Alkermes plc have a grade of A. For those who focus solely on a company’s momentum, further research will need to be conducted into both companies to see if they fit your individual needs as an investor.

Protagonist Therapeutics, Inc. and Alkermes plc’s Estimate Revisions Grades

Company	Ticker	Earnings Estimate
Protagonist Therapeutics, Inc.	PTGX	B
Alkermes plc	ALKS	B

Earnings estimate revisions scores consider the magnitude of a company’s earnings surprise in its last two reported fiscal quarters. Often, positive surprises beget further positive surprises‐or at least continued sales growth (the exact opposite is generally true, too).

Estimate revisions offer an indication of what analysts are thinking about the short-term prospects of a firm. Estimate revisions are based on the statistical significance of a firm’s last two quarterly earnings surprises and the percentage change in its consensus estimate for the current fiscal year over the past month and past three months.

Protagonist Therapeutics, Inc. has a Earnings Estimate Score of 68, which is Positive. Alkermes plc has a Earnings Estimate Score of 74, which is Positive.

The Earnings Estimate Revisions Grade Winner: It’s a Tie!

Looking at the Earnings Estimate Revisions Grade breakdown above, both Protagonist Therapeutics, Inc. and Alkermes plc have a grade of B. For those focusing solely on a company’s estimate revisions, other financial metrics will need to be evaluated to determine whether Protagonist Therapeutics, Inc. or Alkermes plc is a better fit.

Other Protagonist Therapeutics, Inc. and Alkermes plc Grades

In addition to Momentum, Estimate Revisions and Quality, A+ Investor also provides grades for Value and Growth.

Growth investing builds on the idea that stocks of companies exhibiting strong, consistent and prolonged growth outperform those of slower-growth companies. AAII measures growth through consistency of annual sales growth, five-year sales growth rankings adjusted for extreme levels, and consistency of positive annual cash from operations.

Successful stock investing involves buying low and selling high, so stock valuation is an important consideration for stock selection. Buying stocks that are going to go up typically means buying stocks that are undervalued in the first place, although momentum investors may argue that point.

These 2 key factors, when combined with the above, provide a holistic view into a particular stock. Further, by joining A+ Investor you can see whether Protagonist Therapeutics, Inc. and Alkermes plc pass any of our 60+ stock screens that have outperformed the market since their creation.

So, Which Is the Better Investment, Protagonist Therapeutics, Inc. or Alkermes plc Stock?

Overall, Protagonist Therapeutics, Inc. stock has a Momentum Score of 94, Estimate Revisions Score of 68 and Quality Score of 38.

Alkermes plc stock has a Momentum Score of 91, Estimate Revisions Score of 74 and Quality Score of 46.

Comparing Protagonist Therapeutics, Inc. and Alkermes plc’s grades, scores and metrics can act as a solid basis to determine whether they may be a good investment or not. You’ll also want to look at your portfolio’s asset allocation as well as your risk tolerance and financial goals to see if either of these stocks would make a good fit for you. AAII can help you figure out which investments align with your individual needs and preferences.

Investors are encouraged to do their own due diligence and research. In this way, individuals can effectively become managers of their own assets‐without having to rely on others for financial independence. You can count on AAII for timeless articles on financial planning and stock-picking, unbiased research and actionable analysis.

A+ Investor adds to our qualitative teaching with a powerful data suite to help you whittle down investment choices to find stocks, exchange-traded funds (ETFs) or mutual funds that meet your needs.

AAII Disclaimer

We make no representations or warranties that any investor will, or is likely to, achieve profits similar to those shown, because past, hypothetical or simulated performance is not necessarily indicative of future results. Before making an investment decision, you should consider your circumstances and whether the information on our content is applicable to your situation. This information was prepared in good faith, and we accept no liability for any errors or omissions. The full disclaimer can be read here.