Adds analyst comment in paragraph 4

May 9 (Reuters) - Johnson & Johnson JNJ.N said on Friday its experimental psoriasis drug met the main goal of a late-stage study, as the once-daily pill helped patients achieve clear or almost clear skin.

The drugmaker has been working on more convenient treatment options as its injectable psoriasis drug Stelara, which gained over $10 billion in sales last year, faces stiff competition from cheaper rivals.

J&J said last month it expects the drug, icotrokinra, to generate sales of $700 million in 2028.

BTIG analyst Julian Harrison expects icotrokinra to "complement rather than disrupt" market leaders, including J&J's Tremfya and AbbVie's ABBV.N Skyrizi.

Icotrokinra helped 66% of patients with scalp psoriasis and 77% of those with genital psoriasis achieve significantly clear skin compared to 11% and 21% success rate in patients on placebo, respectively, J&J said.

The drug was administered to patients 12 years and older with at least moderate plaque psoriasis affecting "high-impact" areas, including the scalp and genitals, for 16 weeks.

Plaque psoriasis, an immune-mediated condition characterized by thick, scaly patches or plaques, is the most common type of psoriasis. Psoriasis is estimated to affect more than 7.5 million adults in the United States.

The study enrolled 311 patients, who were randomly chosen to receive either icotrokinra or placebo for a period of 16 weeks.

J&J is developing the drug with partner Protagonist Therapeutics PTGX.O.

Icotrokinra is designed to block a protein, IL-23, involved in inflammatory responses and is being tested as a potential treatment for other inflammatory conditions, such as ulcerative colitis.

In a separate late-stage study last year, the drug showed significant skin clearance in patients with moderate-to-severe plaque psoriasis.

(Reporting by Mariam Sunny and Padmanabhan Ananthan in Bengaluru; Editing by Vijay Kishore and Shinjini Ganguli)

((Mariam.ESunny@thomsonreuters.com;))