Three obesity drug milestones still open as the third quarter nears its end

As of September 8, three dated third-quarter commitments across the field of experimental obesity drugs were still unannounced, with 22 days left in the quarter ^[1]. The open items are Structure Therapeutics' guided Phase 3 start for aleniglipron, Viking Therapeutics' guided VANQUISH-2 topline in participants with type 2 diabetes, and the guided start of registrational Phase 3 trials of petrelintide monotherapy from Zealand Pharma and Roche ^[1].

No reason has been disclosed for the timing, and none of the three companies has announced a change to its guidance ^[1].

What the three programs are

Aleniglipron is an oral small-molecule GLP-1 drug. Structure Therapeutics has said it is on track to begin the Phase 3 program in the third quarter of 2026 at a 2.5 mg starting dose, after positive end-of-Phase-2 feedback from the FDA ^[2]. Phase 2 data showed about 16.3% placebo-adjusted weight loss at 44 weeks at the 180 mg dose, which the company describes as potentially best-in-class; that claim rests on a comparison across separate trials, not a head-to-head study ^[1]. Guided market entry is around 2029 ^[1].

Viking Therapeutics is waiting on VANQUISH-2, a Phase 3 trial in people with type 2 diabetes ^[1]. The larger VANQUISH-1 trial in obesity, with about 4,650 participants treated for 78 weeks, is guided to late 2027 ^[1]. In Phase 2, Viking's VK2735 produced up to 12.2% weight loss at 13 weeks as an oral drug and up to 14.7% at 13 weeks as a subcutaneous injection ^[1]. The design of VANQUISH-2, including its size and duration, has not been reported in these updates.

Petrelintide is an amylin-based drug given by injection. In Phase 2 it produced up to 10.7% weight loss at 42 weeks, with tolerability described as placebo-like and no vomiting reported in the group receiving the maximum effective dose ^[1]. Roche and Zealand Pharma have a partnership worth $1.65 billion upfront and up to about $5.3 billion including development and sales milestones ^[1]. A separate Phase 2 trial combining petrelintide with enicepatide is also guided to the second half of 2026 ^[1].

The one company that hit its window

Ascletis dosed the first participant in its global Phase 3 program for ASC30 on August 30, 2026, making it the only company in the group to have met its stated window ^[1][2]. ASC30 is a once-daily oral small-molecule GLP-1 drug. The program covers about 4,600 participants at sites in the United States, Europe and Canada, testing 20 mg, 40 mg and 60 mg maintenance doses over 72 weeks. AURORA-1 enrolls participants without type 2 diabetes; AURORA-2 enrolls those with it ^[2].

Ascletis has guided topline results to the third quarter of 2028, an FDA submission by the end of 2028 and a European submission in early 2029 ^[2]. The company describes ASC30 as a candidate to become the second oral small-molecule GLP-1 in the United States and Europe, which places it behind Eli Lilly's orforglipron (Foundayo) rather than against it ^[2].

Why it matters for patients

None of these programs will change what is available at a pharmacy this year. The drugs that are approved today are tirzepatide (Mounjaro, Zepbound), with roughly 21% weight loss at 72 weeks; semaglutide (Ozempic, Wegovy, Rybelsus), with roughly 15% at 68 weeks; and orforglipron (Foundayo), with roughly 15% ^[1]. Everything described above is still experimental.

What the open windows illustrate is how far out the next choices sit, and how easily those dates move. Aleniglipron's guided market entry is around 2029 ^[1]. Ascletis, the only company that met its own deadline, is guiding to a US filing at the end of 2028 ^[2]. People who have not found an approved drug that works for them, or who cannot tolerate it, are waiting on those timelines.

The programs also differ in ways that could matter. Petrelintide has been studied for tolerability, with gastrointestinal side effects closer to placebo than has been typical for GLP-1 drugs, which is the main reason some patients stop treatment ^[1]. Aleniglipron and ASC30 are pills rather than injections ^[1][2]. Whether any of that translates into a better experience in real use is not yet known; these are mid- and early-stage results from limited numbers of participants.

What happens next

The third quarter ends September 30, 2026 ^[1]. Any of the three open milestones could still be announced before then, or the guidance could be extended; no company has said which ^[1]. Viking's bigger obesity readout, VANQUISH-1, is guided to late 2027 ^[1], and Ascletis has guided topline for ASC30 to the third quarter of 2028 ^[2].