Ascletis Pharma wants to put one of psoriasis medicine’s most proven targets into a pill. Early data suggest it might work. Emphasis on early.

The Hong Kong-listed drugmaker (HKEX: 1672) said in a September 28 press release that its experimental drug ASC50 cut psoriasis severity by 48.9% more than placebo after 28 days of once-daily dosing in a small U.S. study. The effect kept building after dosing stopped. Fifteen days past the final pill, the placebo-adjusted reduction reached 65.9%.

Why should investors care? ASC50 blocks IL-17A, the same inflammatory protein targeted by some of the best-selling injectable psoriasis drugs on the market. A pill that hits it safely would be a serious commercial asset. But this is Phase 1 data, and a lot stands between here and any approval.

What the Study Tested

The trial (NCT07024602) is a randomized, double-blind, placebo-controlled Phase 1 study run at U.S. sites. The portion reported this week enrolled adults with mild-to-moderate plaque psoriasis, who took either 200 mg of ASC50 or a placebo once a day for 28 days.

Efficacy was measured with the Psoriasis Area and Severity Index (PASI). It’s the standard yardstick in psoriasis trials, scoring how much skin is affected and how red, thick, and scaly the plaques are. “Placebo-adjusted” means the placebo group’s improvement has been subtracted out.

Ascletis reported three readings. The reduction was 48.9% at the end of dosing, 60.7% six days after the last dose, and 65.9% at day 15 off drug. The company also pointed to elevated blood levels of IL-17A after treatment, which it says shows the drug was engaging its target.

Safety So Far

According to Ascletis, every adverse event was mild (Grade 1) and short-lived. There were no serious adverse events and no dropouts. The company also stressed that it saw no rise in the liver enzymes ALT or AST and detected no liver safety signal.

A clean liver panel over four weeks is a good start. It says very little about months or years of daily use, which is how psoriasis drugs are actually taken.

The Once-Weekly Pitch

Dosing is the real selling point here. ASC50 showed a steady-state half-life of 6.5 days in patients, meaning it lingers in the body for a long time. Ascletis says that, together with the lasting response after the final dose, supports potential once-weekly oral dosing.

One thing to keep straight. Nobody in this study took ASC50 once a week. Patients took it every day. Weekly dosing is a hypothesis the company still has to test.

What the Release Leaves Out

The gaps are notable. The release does not say how many patients enrolled or how many got placebo. It gives no p-values or confidence intervals. It reports average PASI reduction rather than PASI 75 or PASI 90 responder rates, the share of patients whose scores improved by at least 75% or 90%, which is how later-stage psoriasis trials are usually judged. And it offers no timeline for a Phase 2 trial.

Ascletis also says ASC50’s PASI reduction was comparable to published data for secukinumab, Novartis’s approved injectable IL-17A antibody sold as Cosentyx. The company itself notes that was not a head-to-head study. Different trials, different patients, different timepoints. Suggestive at best, not proof.

Checking the “First-in-Class” Label

The release headline calls ASC50 both “first-in-class” and “best-in-class.” Neither label holds up cleanly.

IL-17A is not a new target. Ascletis itself describes it as biologically and commercially validated. Nor is ASC50 the first oral small-molecule IL-17 inhibitor to reach psoriasis patients. DICE Therapeutics’ DC-806 finished a 28-day Phase 1 psoriasis study in 2022, and published results showed a 43.7% average PASI reduction at its top dose versus 13.3% on placebo. Eli Lilly bought DICE for $2.4 billion, shelved DC-806, and moved a follow-on molecule, DC-853 (LY4100511), into a Phase 2 trial in moderate-to-severe psoriasis. Those DC-806 figures come from a separate trial with a different design, so they are not directly comparable to ASC50’s.

As for “best-in-class,” that simply can’t be judged from a four-week Phase 1 study.

An Oral Option Already Exists

Needle-free psoriasis treatment isn’t new ground, either. In March 2026, the FDA approved Johnson & Johnson’s Icotyde (icotrokinra), a once-daily oral peptide that blocks the IL-23 receptor, for moderate-to-severe plaque psoriasis. It acts on a different step of the same inflammatory pathway. The approval rested on four clinical trials involving about 2,500 patients.

That’s the bar. ASC50’s data come from milder patients over four weeks, while Icotyde and the injectable IL-17 antibodies are approved for moderate-to-severe disease. Milder disease can respond differently, so the numbers don’t carry over neatly.

Where This Leaves Ascletis

For Ascletis, ASC50 sits outside its home turf. The company describes itself as focused on metabolic disease, and its lead program is ASC30, an oral GLP-1 drug for weight management and diabetes. A credible oral IL-17A drug would give it a second story in immunology.

The next real test is a larger trial in moderate-to-severe patients, scored on responder rates and ideally trying the once-weekly schedule. Ascletis hasn’t said when that will start. This article covers early-stage clinical data and is not medical or investment advice.

Sources

• Ascletis Pharma: Ascletis Announces Positive Results from 28-Day Proof-of-Concept Clinical Study in U.S. for ASC50, a First-in-Class and Best-in-Class Oral Small Molecule IL-17A Inhibitor for the Treatment of Plaque Psoriasis, PRNewswire, September 28, 2026. Primary source release.
• Clinical Proof of Concept for Small Molecule Mediated Inhibition of IL-17 in Psoriasis (PubMed Central), cited for DICE Therapeutics’ earlier 28-day DC-806 Phase 1 psoriasis results, used to check the release’s “first-in-class” claim.
• Fierce Biotech: Eli Lilly Rolls the Dice, Axing Psoriasis Prospect and Pivoting to Follow-Up 1 Year After $2.4B Buyout, cited for Lilly’s acquisition of DICE, the shelving of DC-806, and the DC-853 Phase 2 program.
• ClinicalTrials.gov: A Study of LY4100511 (DC-853) in Adult Participants With Moderate-to-Severe Plaque Psoriasis (NCT06602219), cited for the design and population of Lilly’s competing Phase 2 oral IL-17 trial.
• Johnson & Johnson: FDA Approval of ICOTYDE (icotrokinra) Ushers in New Era for First-Line Systemic Treatment of Plaque Psoriasis With a Targeted Oral Peptide, cited for competitive-landscape context on the already-approved oral psoriasis therapy icotrokinra.
• U.S. Food and Drug Administration: Drug Trials Snapshots, ICOTYDE, cited for Icotyde’s approval date and the size of the trial program behind it.

Editorial Disclosure

This article reports on early-stage clinical trial data announced in a press release issued by Ascletis Pharma Inc. on September 28, 2026, regarding ASC50, with competitive-landscape context on DICE Therapeutics’ DC-806, Eli Lilly’s DC-853 (LY4100511), and Johnson & Johnson’s icotrokinra drawn from the independent sources cited above, since the original release did not address them. Securities discussed: Ascletis Pharma Inc. (Hong Kong Stock Exchange: 1672), Eli Lilly and Company (NYSE: LLY), Johnson & Johnson (NYSE: JNJ), and Novartis AG (SIX: NOVN; NYSE: NVS). BioTech Stocks Daily has not received, nor will it accept, any compensation, direct or indirect, from Ascletis Pharma, Eli Lilly, Johnson & Johnson, Novartis, or any other corporate or third-party sponsor for the preparation or publication of this coverage. No staff member, principal, or affiliate of BioTech Stocks Daily holds a position, option, or financial interest in any of the securities mentioned as of the date of publication. Statements regarding potential once-weekly dosing, future clinical trials, development timelines, eventual regulatory approval prospects, and potential commercial competition are forward-looking statements. They involve substantial risks, regulatory uncertainties, and scientific variables; actual clinical outcomes, development timelines, and commercial approvals may differ materially. ASC50 is an investigational drug that has not been approved by the FDA or any other regulator for any use. Clinical-stage biotechnology investments carry an extreme degree of financial risk. Drug development is subject to high rates of clinical failure, regulatory rejection, and market competition, which can result in the total loss of invested capital. This article is published strictly for independent news reporting, market context, and educational purposes only. It does not constitute an investment recommendation, endorsement, or professional financial, legal, or tax advice. Furthermore, this content is not medical advice; patients and healthcare providers should consult appropriate clinical professionals for medical guidance.

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