✦ MariTide: Twenty Percent, Then SixteenThin moat

Amgen (AMGN) — the future bets

MariTide produced up to 20% weight loss in completers and up to 16% on the full count, and Amgen's shares fell after both.

MariTide is Amgen's entry into obesity, and its data have twice disappointed investors while remaining genuinely good. The Phase 2 study enrolled 592 adults1. In November 2024 Amgen reported up to approximately 20% average weight loss at week 52 without a weight loss plateau in people without type 2 diabetes, and up to approximately 17% in people with it2. Amgen's shares dropped 12% that day3; BioPharma Dive noted that the rate of participants discontinuing MariTide appeared higher than what was reported in testing for those weekly medicines4.

MariTide Phase 2 average weight loss at 52 weeks (%, up to)about 20%Completers, no diabetesabout 17%Completers, with diabetes16%Full analysisAmgen Form 10-K FY2024; BioPharma Dive, 23 June 2025
The number depends on who is counted.

The full analysis came in June 2025. Measured across everyone who started the study, not just those who completed it, participants lost an average of up to 16% of their body weight5. The shares fell 4%6, or $14.58 to $274.75 on another account7.

The second year was better news. Amgen reported that the large majority of participants maintained the weight loss achieved in Part 1 for an additional 52 weeks on a lower monthly dose or quarterly dose8. That supports the product's main argument, infrequent dosing.

The Phase 3 programme is large: MARITIME-1 and MARITIME-2 are ongoing, and studies in heart disease, heart failure, sleep apnoea, switching and extensions are enrolling, with three more in type 2 diabetes to start in 20269. Amgen has not disclosed when the first will read out. The market it would enter is described on Eli Lilly's pages.

MariTide will be judged on the first Phase 3 result. Weight loss near 20% on the full population with fewer discontinuations would restore the case; a result near 16% again would confirm a respectable drug that arrives late with no efficacy advantage.

Moat trajectory: Holding steady

Phase 3 enrolling; no readout date.

The number that tests this moat
Reported
MariTide average weight loss, latest full analysis
Up to about 16% at 52 weeks (full Phase 2 analysis); up to about 20% among completers

The efficacy benchmark; Phase 3 results below 16% would leave it with no advantage but dosing.

Source: BioPharma Dive, full MariTide data ↗
References
  1. ReportedThe Phase 2 study enrolled 592 adults.
    Amgen press release on the 52-week MariTide Phase 2 study in obesity - 592 adults enrolled. — November 2024 · publ. 26 November 2024 · source ↗
  2. ReportedIn November 2024 Amgen reported up to approximately 20% average weight loss at week 52 without a weight loss plateau in people without type 2 diabetes, and up to approximately 17% in people with it.
    Amgen Form 10-K for fiscal 2024 - the MariTide Phase 2 results, the Horizon inventory step-up and 2024 financial statements. — FY2024 · publ. February 2025 · source ↗
  3. ReportedAmgen's shares dropped 12% that day; BioPharma Dive noted that the rate of participants discontinuing MariTide appeared higher than what was reported in testing for those weekly medicines.
    Yahoo Finance / Investing.com - Amgen shares dropped 12% after the MariTide study results. — November 2024 · publ. 26 November 2024 · source ↗
  4. ReportedAmgen's shares dropped 12% that day; BioPharma Dive noted that the rate of participants discontinuing MariTide appeared higher than what was reported in testing for those weekly medicines.
    BioPharma Dive on the MariTide Phase 2 topline results and discontinuation rates. — November 2024 · publ. 26 November 2024 · source ↗
  5. ReportedMeasured across everyone who started the study, not just those who completed it, participants lost an average of up to 16% of their body weight.
    BioPharma Dive on the full MariTide Phase 2 data at the American Diabetes Association meeting - average weight loss of up to 16% and a 4% share fall. — June 2025 · publ. 23 June 2025 · source ↗
  6. ReportedThe shares fell 4%, or $14.58 to $274.75 on another account.
    BioPharma Dive on the full MariTide Phase 2 data at the American Diabetes Association meeting - average weight loss of up to 16% and a 4% share fall. — June 2025 · publ. 23 June 2025 · source ↗
  7. ReportedThe shares fell 4%, or $14.58 to $274.75 on another account.
    GuruFocus - Amgen shares fell $14.58, or 5%, to $274.75 after the full MariTide data. — June 2025 · publ. 23 June 2025 · source ↗
  8. ReportedAmgen reported that the large majority of participants maintained the weight loss achieved in Part 1 for an additional 52 weeks on a lower monthly dose or quarterly dose.
    Amgen fourth-quarter and full-year 2025 results release, Form 8-K exhibit 99.1 - product sales for 2024-2025, non-GAAP EPS and 2026 guidance. — FY2025 · publ. 3 February 2026 · source ↗
  9. ReportedThe Phase 3 programme is large: MARITIME-1 and MARITIME-2 are ongoing, and studies in heart disease, heart failure, sleep apnoea, switching and extensions are enrolling, with three more in type 2 diabetes to start in 2026.
    Amgen second-quarter 2026 results release, Form 8-K exhibit 99.1 - pipeline and clinical updates. — Q2 2026 · publ. 4 August 2026 · source ↗
Sources
Generated September 28, 2026