Topical Bimiralisib Shows 92% Clearance Rate for Patients with Actinic Keratosis

In a phase 2 proof-of-concept trial, treatment with topical bimiralisib gel 2% has achieved high rates of actinic keratosis lesion clearance and has been well tolerated in patients with this condition.1

These findings, announced by Torqur AG, were presented at the 2025 European Academy of Dermatology and Venereology (EADV) Congress in Paris. The high clearance rates and tolerability findings in these phase 2 proof-of-concept results for topical bimiralisib gel 2% underscore the drug’s potential in patients with actinic keratosis.

“These results show that bimiralisib gel 2% has both efficacy and safety across different grades of actinic keratosis,” Alexander Navarini, MD, PhD, chairman of dermatology at University Hospital Basel and lead principal Investigator, said in a statement.1 “This represents a promising new non-invasive option for patients, addressing a significant unmet need in dermatology.”

Actinic keratosis is a condition known to impact over 10% of the European population. It is the most prevalent precancerous skin condition and has been linked with dysregulation of the PI3K/mTOR signaling pathway. Bimiralisib gel, a selective pan-PI3K/mTOR inhibitor, provides a novel mechanism-based therapeutic strategy designed to target early-stage skin lesions in an efficacious and safe manner.

These new data resulted from a randomized, multicenter, phase 2 study evaluating the use of bimiralisib gel as a field-directed therapy for actinic keratosis lesions found on the scalp, face, and/or dorsal hands. The study involved the recruitment of 46 participants across 2 leading dermatology centers in Switzerland: University Hospital Basel and Lausanne University Hospital.

“With actinic keratosis being the most common precancerous skin condition, these data highlight the great potential of this targeted topical therapy to counter progression to squamous cell carcinoma,” Olivier Gaide, MD, PhD, head of the Center of Excellence for Skin Cancer and Melanoma at Lausanne University Hospital and principal trial investigator, said in a statement.1

Gaide and coauthors’ findings demonstrated that bimiralisib’s strong clinical efficacy and tolerability reinforce the topical gel’s potential for additional development. They noted that among patients with Olsen grade 1 lesions, attainment of complete or near-complete response appeared in 92% of such individuals.

The investigative team found, across all participants, 52% of those in the 2-week treatment cohort and 71% in the 4-week cohort attained an Investigator’s Global Assessment (IGA) score of 0–1, suggesting complete or partial clearance of lesions. The team additionally found that study participants had at least some degree of lesion reduction following initial therapy.

Clearance of patients’ lesions was seen among both Olsen grade 1 and grade 2 actinic keratosis, with a subgroup analysis indicating a 48% complete or near-complete response rate among grade 2 individuals. Overall, they highlighted bimiralisib gel’s strong tolerability, noting that the majority of treatment-related adverse events were shown to be mild, localized skin reactions.

The investigators specifically identified only four grade 2 events among study subjects, all of which resolved without the need for medical intervention. Retreatment during an optional 8-week extension phase was feasible, and the team found did not result in any new or significant safety concerns. Additional lesion improvements, including further instances of complete clearance, were noted with continued therapy.

“Presenting these Phase 2 results at Europe’s most prestigious dermatology congress is a tremendous milestone,” Vladimir Cmiljanovic, CEO of Torqur AG, said in a statement.1 “The high rates of clearance and consistently favorable tolerability profile underscore bimiralisib’s potential to become a new standard for patients with actinic keratosis. We are now preparing for the pivotal Phase 3 clinical trials and discussing with potential partners to bring this therapy closer to patients worldwide.”

References

1. Bimiralisib, Topical PI3K/mTOR Inhibitor Shows Up To 92% Clearance Rate And Superior Tolerability In Proof-Of-Concept Actinic Keratosis Study. Torqur AG. October 6, 2025. https://www.businesswire.com/news/home/20251003884166/en/Bimiralisib-Topical-PI3KmTOR-Inhibitor-Shows-Up-To-92-Clearance-Rate-And-Superior-Tolerability-In-Proof-Of-Concept-Actinic-Keratosis-Study.

2. Janku F, Choong GM, Adjei AA, et al. A Phase I Study of the Oral Dual-Acting Pan-PI3K/mTOR Inhibitor Bimiralisib in Patients with Advanced Solid Tumors. Cancers (Basel). 2024 Mar 13;16(6):1137. doi: 10.3390/cancers16061137. PMID: 38539472; PMCID: PMC10969742.