VK2735 has become one of the most closely watched obesity drugs that neither Eli Lilly nor Novo Nordisk owns. In its October 28 third-quarter update, Viking Therapeutics said its two injectable Phase 3 trials were fully enrolled, its separate oral Phase 3 program had begun, and it held approximately $960 million in cash and short-term investments after closing a financing that generated about $575 million in gross proceeds.
The more interesting part of the story is quieter. Viking is building a case around how patients might maintain their weight loss after an initial period of weekly injections. Instead of requiring weekly treatment indefinitely, VK2735 might eventually support injections every other week or every four weeks.
That bet looks promising after a 12-week maintenance experiment. The longer test is still ahead. Viking expects its extended Phase 3 studies, including investigations of less-frequent dosing, to produce results in 2028.
For a company trying to compete with the established obesity-drug market, dosing flexibility could be a meaningful advantage. But convenience is valuable only if the treatment keeps working, remains tolerable and can be delivered at a sustainable cost.
Where VK2735’s Phase 3 Program Stands
VK2735 is an investigational dual agonist of the GLP-1 and GIP receptors, the same receptor combination targeted by Eli Lilly’s tirzepatide. Viking is developing the compound in both subcutaneous and oral formulations.
The injectable program, called VANQUISH, consists of two randomized, double-blind, placebo-controlled Phase 3 trials. VANQUISH-1 enrolled approximately 4,500 adults with obesity in about five months. VANQUISH-2 enrolled approximately 1,000 adults with obesity and type 2 diabetes in about nine months.
Both studies are evaluating weekly VK2735 doses of 7.5 mg, 12.5 mg and 17.5 mg against placebo over 78 weeks. The primary endpoint is percentage change in body weight from baseline, with additional assessments of safety and the proportions of patients achieving clinically meaningful weight-loss thresholds.
Viking reported that enrollment in both trials was complete and that the studies remained on track for completion in 2027. Their size gives the company a considerably more substantial clinical development program than the earlier Phase 2 studies on which much of VK2735’s initial reputation was built.
The oral program is separate. In October, Viking initiated SUNRISE-1 and SUNRISE-2, each targeting approximately 560 adults. Those trials will evaluate daily VK2735 tablets at 27.5 mg, 35 mg and 55 mg against placebo over 68 weeks.
Viking previously reported up to 12.2% mean weight loss after 13 weeks of oral treatment in Phase 2. That result supports further investigation, but it does not establish the tablet’s long-term efficacy or how it will compare with competing oral obesity drugs.
Enrolling 4,500 people in five months demonstrates the company’s ability to recruit a large study population. It says nothing about whether the treatment will succeed.
The Maintenance Data Behind Viking’s Monthly Dosing Pitch
On September 22, Viking announced topline results from Part 1 of its VK2735 maintenance study, a randomized trial involving approximately 180 adults with obesity across 11 treatment groups.
The study began with a 21-week induction period. Participants received weekly VK2735 injections at escalating doses or placebo. Those treated with active VK2735 reached final weekly doses ranging from 15 mg to 22.5 mg.
By week 21, mean weight reductions across the active dose groups ranged from approximately 16% to 19%, compared with essentially no change in the original placebo group. Weight loss was still progressing at the end of induction.
Participants receiving weekly VK2735 then entered a 12-week maintenance phase in which they switched to less frequent active injections, placebo or, in one exploratory cohort, continued weekly treatment.
At week 33, the groups switched to injections every other week retained between 83% and 97% of their week-21 weight loss. The combined every-other-week group retained an average of 90%.
The monthly groups retained between 82% and 90% of their previous weight reduction, with a combined mean of 85%. Participants switched from active weekly treatment to placebo retained 61% of their weight loss.
These percentages describe how much of the original weight reduction remained, not the percentage of total body weight lost. A person who lost 20% of baseline weight and retained 90% of that reduction would still be approximately 18% below baseline.
The distinction between the best-performing groups and the pooled averages also matters. Viking’s headline figures of up to 97% and 90% are accurate, but they represent particular dosing groups rather than everyone assigned to the two less-frequent schedules.
The best-performing monthly efficacy group included just 11 participants. Small treatment arms can show encouraging signals, but they provide less certainty about how a dosing strategy will perform in larger and more varied populations.
Tolerability during maintenance was encouraging. Viking reported nausea in approximately 5% of participants across the combined every-other-week groups and 4.5% across the combined monthly groups. There was one adverse-event-related treatment discontinuation in each combined active maintenance group.
Those observations suggest that less frequent dosing might be feasible without a major short-term increase in gastrointestinal side effects. They do not establish the safety of monthly treatment over multiple years.
Why Twelve Weeks Cannot Settle the Weight-Regain Question
The maintenance study’s central limitation is time. Twelve weeks is a narrow window for determining whether people can maintain substantial weight loss after reducing treatment frequency.
Weight regain following the withdrawal of GLP-1-based treatments can develop over many months. The 61% of previous weight loss retained by the placebo-switch group at week 33 illustrates why a short observation period can make an interrupted treatment appear more durable than it ultimately proves to be.
There is another limitation in the study design. Participants entered the maintenance phase after completing an initial period of closely monitored weekly treatment. That is different from the experience of patients managing medication access, insurance changes, missed injections and side effects outside a trial.
The reported maintenance percentages therefore should not be interpreted as proof that monthly VK2735 can provide equivalent long-term weight control to weekly treatment.
The study was also divided into numerous small groups testing different doses. Although the reported active maintenance groups performed better than placebo over the study period, choosing the most favorable percentage from each dosing category can exaggerate how certain the broader result is.
An exploratory group continuing weekly VK2735 at 17.5 mg reached approximately 21.7% mean weight loss by week 33, without an observed plateau. That finding suggests further weight reduction could be possible with continued weekly dosing, but it came from a small exploratory cohort and should not be treated as the result of a pivotal trial.
The maintenance question also concerns more than weight. Longer studies will need to characterize tolerability, treatment interruptions, weight trajectories and metabolic outcomes. The optimal maintenance dose may not be the one that produces the largest early weight reduction.
Twelve weeks of maintenance is a promising start. Weight regain is usually a longer story.
Viking’s $575 Million Financing Gives the Program More Room
Viking’s financial position has become an important part of its clinical development story. On September 28, the company closed concurrent public offerings of common stock and convertible senior notes, generating approximately $575 million in gross proceeds and an estimated $547.8 million after underwriting discounts and offering expenses.
The financing was not entirely an equity raise. It included $258.75 million in principal amount of 2% convertible senior notes due in 2032, alongside the common-stock offering. That structure provided capital while introducing debt obligations and potential future dilution.
At September 30, Viking reported approximately $960 million in cash, cash equivalents and short-term investments, compared with approximately $706 million at the end of 2025. The company said these resources would support ongoing Phase 3 development, earlier-stage research and preparations for potential commercialization.
The cost of that development effort is already visible. Research and development expenses increased to $166.8 million in the third quarter, from $90.0 million a year earlier. Viking reported a quarterly net loss of $183.2 million, compared with $90.8 million in the corresponding 2025 period.
The spending reflects the scale of multiple late-stage clinical studies, associated manufacturing work and preparations for a possible commercial future. It is not evidence that a launch will occur or that regulatory approval is assured.
Large obesity trials require substantial capital, and funding them before establishing pivotal efficacy creates financial risk. But the cash balance reduces Viking’s immediate dependence on another financing transaction as its principal injectable studies approach their planned completion.
For investors, the distinction is straightforward: $575 million was the gross amount raised in September, not a new amount of dedicated clinical funding added on top of the reported $960 million cash balance.
The 2027 and 2028 Calendar Will Test Different Questions
Viking’s next stages of development will answer separate questions about VK2735’s effectiveness, durability and flexibility.
The company expects the main VANQUISH injectable studies to complete in 2027. Those trials will provide the larger, longer-term evidence needed to evaluate weekly VK2735’s efficacy and safety in adults with obesity, including those with type 2 diabetes.
The VANQUISH extension studies are expected to begin in the first quarter of 2027. Eligible participants may continue treatment for up to another 52 weeks, allowing the collection of additional long-term safety and efficacy data.
Critically, the VANQUISH-1 extension will include selected every-other-week and monthly dosing regimens. Viking expects results from the extension studies in 2028.
That is the longer test of the company’s maintenance thesis. Retaining most of a previous weight reduction over three months is one finding. Establishing that a practical, less-frequent regimen can sustain weight control for much longer is a different and more commercially meaningful result.
Another set of evidence should arrive sooner. Viking has initiated Part 2 of its separate maintenance study, involving approximately 195 adults with obesity. Following 21 weeks of weekly injectable treatment, participants will transition to maintenance options including daily oral VK2735, every-other-week injections, monthly injections or placebo.
Viking expects Part 2 results in 2027. Those findings could help clarify the role of oral maintenance and identify doses worth studying further. They will not replace the larger extension studies expected in 2028.
The company’s development timetable is therefore more complicated than a single upcoming Phase 3 readout. The 2027 studies address pivotal weight-loss efficacy and shorter maintenance strategies. The 2028 extensions are expected to give a more substantial view of sustained treatment and less-frequent dosing.
All projected completion and reporting dates remain company expectations rather than guarantees.
Why Monthly VK2735 Could Matter More Than Another Weight-Loss Record
The obesity-drug market is moving beyond the question of which medicine produces the greatest percentage reduction in body weight. Long-term treatment raises a different set of concerns: convenience, adherence, tolerability, affordability and the ability to sustain benefits over years.
A regimen given every four weeks would involve approximately 13 injections annually, compared with about 52 for a weekly medicine. For patients who find frequent injections burdensome, that difference could be meaningful.
However, fewer injections do not automatically mean lower cost. The total expense would depend on pricing, dose requirements, supply arrangements, insurance coverage and the economics of manufacturing the product.
The possibility of switching between the same active compound’s injectable and oral formulations could also offer flexibility. Yet clinical studies must establish whether changing formulations maintains appropriate exposure, tolerability and efficacy. Convenience cannot be assumed to translate into better treatment persistence.
Other developers are exploring longer-acting medicines and maintenance strategies as well. The larger commercial opportunity is not simply reducing injection frequency, but making long-term obesity treatment manageable without sacrificing results.
That is why maintenance research deserves attention alongside peak weight-loss figures. A medicine that produces substantial initial weight loss but cannot support sustainable treatment may offer a different clinical and commercial proposition from one that balances effectiveness with long-term practicality.
Viking’s September data provide an encouraging early signal, not a final answer. The sample was small, the maintenance period short, and the less-frequent regimens remain investigational.
VK2735 is now supported by an extensive Phase 3 development program and a stronger balance sheet. What remains unknown is whether Viking can translate those advantages into an approved treatment, and whether monthly maintenance will remain effective over the longer periods that matter to patients.
The obesity race is no longer only about weight lost. It is about weight kept.
The 2027 VANQUISH program will test whether VK2735 can deliver competitive longer-term weight loss. The 2028 extension results should provide a stronger answer to whether less-frequent maintenance can become the feature that distinguishes it.
Primary source: Viking Therapeutics Reports Third Quarter 2026 Financial Results and Provides Corporate Update, SEC Exhibit 99.1, October 28, 2026.
Maintenance study: Viking Therapeutics Announces Positive Topline Results from VK2735 Maintenance Study, September 22, 2026.
Financing documentation: Viking Therapeutics Announces Closing of Concurrent Stock and Convertible Note Offerings, September 28, 2026.
Related Grey Pepper reporting: Can a Different Peptide Help Keep Weight Off? and AbbVie’s Monthly Amylin Injection.
