KNSA vs REGN: Which Is the Better Buy in 2026?

Same yardstick, side by side (as of August 2026). Valuation lined up like this is most meaningful for two names in the same corner of the market, which these are. Figures are approximate; verify before investing.

Reading it: REGN is the cheaper of the two on forward earnings, but cheaper is not the same as better. Pair the valuation with growth (how far the forward P/E sits below the trailing P/E) and risk (beta) before you decide.

The metrics above tell you which is the marginally better business. The bigger risk for most people is not picking the slightly worse stock, it is over-concentrating. KNSA and REGN share themes, so owning both, or adding either to what you already hold, can quietly push a large share of your portfolio into one bet.

This is the part a generic comparison page cannot answer, because it depends on what you own. Connect your brokerage and Walnut shows your real, combined KNSA and REGN exposure, flags overlap with your existing positions, and tells you if adding one would tip you past a concentration you are comfortable with, read-only by default, with your login staying at your broker. Walnut is not an investment adviser.

Kiniksa Pharmaceuticals (Nasdaq: KNSA) is a commercial-stage biopharmaceutical company focused on immune-modulating and cardiovascular therapies. Its franchise is ARCALYST (rilonacept), an IL-1 blocker approved for recurrent pericarditis (a painful inflammatory condition of the heart lining) that it commercializes in the US under a collaboration with Regeneron. ARCALYST drove roughly $677.5 million of net product revenue in 2025, up about 62% from 2024, and the company reported roughly $214.3 million in Q1 2026 (up about 56% year over year), leading management to raise full-year 2026 ARCALYST guidance to roughly $930 to $945 million.

Full KNSA guide

Regeneron makes money primarily through two large franchises. Dupixent, an anti-inflammatory antibody used for eczema, asthma, COPD, and other conditions, is developed and commercialized in collaboration with Sanofi, and Regeneron records its share through Sanofi collaboration revenue (about $1.6 billion in Q1 2026, up roughly 36%). Eylea and the higher-dose Eylea HD treat retinal diseases such as wet age-related macular degeneration and diabetic eye disease, generating combined U.S. net product sales of about $941 million in Q1 2026, with Eylea HD now roughly half of that mix. Libtayo in oncology and a pipeline of nearly 50 clinical candidates round out the revenue base.

Full REGN guide

Both fit overlapping themes, but they are not interchangeable. The useful comparison is which set of drivers and risks you want exposure to.

• KNSA drivers: ARCALYST adoption in recurrent pericarditis; Profitable growth profile.
• REGN drivers: Dupixent keeps compounding; A deep, diversified pipeline.

A faster-growing, richer-valued name usually swings harder, so it suits a longer horizon and a higher tolerance for volatility; a steadier, more cash-generative business suits a more conservative or income-minded investor. The honest test is which set of risks you could hold through a drawdown: The dominant risk is single-product concentration: essentially all revenue depends on ARCALYST in one indication, so any competitive entry, reimbursement pressure, safety signal, or eventual loss of exclusivity would be material. For REGN, the clearest risk is Eylea biosimilar erosion.

Growth-minded investors who believe the theme has years to run tend to accept the richer multiple for more upside; value-minded investors lean toward the cheaper forward earnings and steadier profile. Pick KNSA if you believe its drivers more; REGN if you believe its. Many investors hold both, but since they share themes, that is a concentrated bet, not diversification. Decide deliberately and check overlap. For the full detail, see the KNSA and REGN guides.

KNSA. As of July 2026, Kiniksa carried a market cap of roughly $5.2 billion against trailing revenue near $754 million and net income around $73 million, for a trailing P/E in the mid-70s. That multiple reflects both rare biotech profitability and expectations that ARCALYST keeps compounding toward the raised 2026 guidance of roughly $930 to $945 million.

REGN. Figures are approximate and tied to the asOf date; verify current numbers with a live quote before acting. Regeneron reported about 19% revenue growth and adjusted EPS of roughly $9.47 in Q1 2026, beating estimates, and authorized an additional $3 billion buyback. The mid-teens P/E reflects the market weighing strong Dupixent growth against expected Eylea biosimilar erosion.

Headline figures (approximate, JULY 2026): KNSA shows revenue (ttm) ~$754M, net income (ttm) ~$73M, market cap ~$5.2B, p/e (trailing) ~74x; REGN shows total revenue (ttm, approx) ~$14 billion, q1 2026 total revenue ~$3.6 billion (up ~19% YoY), dupixent global net sales (q1 2026) ~$4.9 billion (up ~31%), eylea + eylea hd u.s. net sales (q1 2026) ~$941 million combined.

KNSA and REGN are related but distinct: same themes, different businesses and risks. Neither wins in the abstract; the right pick is whichever thesis you actually believe, sized so you are not over-concentrated in one theme. Walnut can show your combined KNSA and REGN exposure against your real portfolio. It is not an investment adviser.