The GLP-1 Competitive Landscape: Pfizer's Monthly Injectable and Viking's Phase 3 Expansion Reshape the Race for Third

The GLP-1 Competitive Landscape: Pfizer's Monthly Injectable and Viking's Phase 3 Expansion Reshape the Race for Third

The multi-billion dollar GLP-1 receptor agonist sector remains heavily dominated by the duopoly of Eli Lilly and Company (NYSE: LLY) and Novo Nordisk A/S (NYSE: NVO). Lilly maintains a $1.01 trillion market capitalization, supported by a blowout Q1 2026 revenue of $19.80 billion and the successful FDA approval of its oral non-peptide GLP-1 Foundayo (orforglipron) on April 1, 2026. Novo Nordisk continues to defend its territory, recently securing UK MHRA approval for its once-daily oral Wegovy pill on June 12, 2026, to compete alongside its injectable franchise.

However, the aggressive race for "third place" behind the duopoly is undergoing a dramatic transformation. While early competitors focused primarily on daily oral formulations to disrupt weekly injectables, the emerging clinical landscape is rapidly shifting toward less frequent monthly dosing and next-generation combinations, compressing the valuations of pure-play oral candidates.

+-------------------------------------------------------------------------+
|                        GLP-1 COMPETITIVE LANDSCAPE                      |
+-------------------------------------------------------------------------+
|  DUOPOLY LEADERS:                                                       |
|  - Eli Lilly (LLY): Zepbound, Mounjaro, Oral Foundayo (Approved 2026)    |
|  - Novo Nordisk (NVO): Wegovy, Ozempic, Oral Wegovy Pill (Approved 2026) |
+-------------------------------------------------------------------------+
|  THE SEVERE RACE FOR "THIRD PLACE" (Monthly Dosing & Oral Disruptors)   |
|                                                                         |
|  1. Pfizer (PFE) - Berobenatide (PF'3944)                               |
|     - Acquired Metsera in late 2025 in a $7B+ deal.                     |
|     - Phase 2b ADA 2026: 12.3% placebo-adjusted weight loss on monthly  |
|       maintenance. Advancing 10 Phase 3 trials in 2026.                 |
|                                                                         |
|  2. Amgen (AMGN) - MariTide                                             |
|     - Monthly or less frequent injectable dual GIP/GLP-1.               |
|     - Phase 2 data showed up to 20% weight loss, advancing to Phase 3.  |
|                                                                         |
|  3. Viking Therapeutics (VKTX) - VK2735                                 |
|     - Subcutaneous dual GLP-1/GIP in Phase 3 VANQUISH-1/2 (data 2027).  |
|     - Exploratory Phase 1 Maintenance Study readout expected in Q3 2026 |
|       evaluating transitions to monthly SC or oral dosing.              |
|     - Appointed former Amylin executive Dr. Hubert Chen as CMO.         |
|                                                                         |
|  4. Structure Therapeutics (GPCR) - Aleniglipron                        |
|     - Pure-play oral GLP-1 in Phase 3 mid-2026.                         |
|     - Facing valuation pressure (PT cut to $70) due to monthly injectable|
|       convenience competition.                                          |
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1. Pfizer Emerges as a Heavyweight Competitor

Following its $7.0 billion upfront (up to $10 billion with CVRs) acquisition of Metsera in November 2025, Pfizer (NYSE: PFE) has emerged as a major competitive force. At the June 2026 ADA Meeting, Pfizer presented detailed Phase 2b data for berobenatide (PF'3944, formerly MET-097i), an ultra-long-acting injectable GLP-1 peptide.

• In the VESPER-3 study, patients on monthly maintenance dosing achieved up to 12.3% mean placebo-adjusted weight loss at week 28 with no weight-loss plateau, demonstrating that patients can successfully transition from weekly titration to monthly maintenance injections.
• Pfizer is launching a massive 10-study Phase 3 program in 2026, including VESPER-6 for monthly maintenance, positioning berobenatide as a direct monthly threat to weekly therapies.

2. Viking Therapeutics Strengthens Clinical and Executive Footprint

Viking Therapeutics (NASDAQ: VKTX) is accelerating its clinical development for VK2735, a dual GLP-1/GIP agonist. On June 11, 2026, Viking appointed former Amylin Pharmaceuticals executive Dr. Hubert C. Chen as Chief Medical Officer, signaling a transition toward regulatory filings and eventual commercialization.

• Viking has completed enrollment in its Phase 3 VANQUISH-1 and VANQUISH-2 weekly subcutaneous trials, with data expected in 2027.
• Crucially, Viking expects a readout in Q3 2026 for its exploratory Phase 1 Maintenance Study. This study evaluates transitioning patients from weekly SC injections to biweekly or monthly SC dosing, as well as daily or weekly oral dosing. A positive readout would provide Viking with a highly flexible, dual-formulation maintenance platform.

3. Valuation Pressure Mounts on Oral-Only Biotech Players

The rise of highly effective monthly injectables—specifically Pfizer's berobenatide and Amgen’s monthly/less-frequent GIP/GLP-1 candidate MariTide—is reshaping the commercial expectations for pure-play oral weight-loss biotechs.

• On June 11, 2026, H.C. Wainwright cut its price target on Structure Therapeutics (NASDAQ: GPCR) from $100 to $70, citing competitive pressure in the mid-BMI market from Pfizer’s monthly injectable and Lilly's low-dose retatrutide.
• While Structure is moving its oral candidate aleniglipron into Phase 3 in mid-2026, it faces a higher bar to prove that its daily oral regimen can commercially outcompete the extreme convenience of a once-monthly injection¹.

Quotes

"Ghosh pointed to competitive pressure from retatrutide’s low-dose profile and Pfizer’s once-monthly injectable, which creates a new bar in the same mid-BMI market that oral treatments are targeting." — Investing.com, June 11, 2026

"joining the Viking team at this exciting time of growth is an incredible opportunity, as obesity and metabolic disorders are among the most significant health challenges of our time," — Viking CMO Dr. Hubert C. Chen, June 11, 2026