Genmab Advances New ADC Targeting SLITRK6 Despite Prior Discontinuations

Genmab is advancing a new molecule acquired through its $1.8bn takeover of ProfoundBio into clinical development, suggesting the company is not ready to give up on tapping the assets from this deal despite several recent discontinuations.

The asset in question is PRO1106, now coded GEN1106, an ADC targeting SLITRK6. This target is highly unusual, as the only other similarly acting industry project is Astellas's ASG-15E. According to a new clinicaltrials.gov listing, GEN1106 started phase 1 in February 2026, but the precedent isn't great: Astellas discontinued ASG-15E in 2017.

ASG-15E likely lacked a therapeutic window. A dose of 1mg/kg was selected as the go-forward dose in phase 1, having shown a 38% response rate in bladder cancer, but dose-limiting toxicities became evident as early as at 0.5mg/kg. SLITRK6 (NTRK-like protein 6) plays a role in neural development, but no other companies have attempted to target it with an ADC or any other modality.

The failure of ASG-15E need not imply the same fate for GEN1106, as the two projects differ structurally. ASG-15E was derived from a 2007 deal between Astellas and Seattle Genetics (now part of Pfizer) and used that company's MMAE payload, while GEN1106 employs a topoisomerase 1 inhibitor, likely the same one used in ProfoundBio's lead, rinatabart sesutecan.

Rinatabart sesutecan, an anti-FRα ADC, is still very much in play, though competitor data, especially from Lilly and AstraZeneca, might be eclipsing it. ProfoundBio ADCs recently discontinued comprise molecules against EGFR x cMet, CD70 and PTK7, and it's not clear how many of its other projects beyond GEN1106 might still be taken forward into the clinic.

Other notable clinical entrants listed on the clinicaltrials.gov database between February 12 and 18, 2026, include Boundless Bio's BBI-940, a molecule described as an oral kinesin degrader. The company says BBI-940 hits a previously undrugged kinesin involved in DNA segregation, including ecDNA segregation, during mitosis. The Komodo-1 study in breast cancer began in late February 2026.

Boundless Bio is a distressed biotech hit hard by the discontinuation of work on CHK1 inhibition, the premise on which it listed on Nasdaq in 2024. The company switched its focus to BBI-940 last month.

Additional clinical entrants include Humanwell's anti-FGFR2b MAb HWS116 and GeneScience's PI3Kα inhibitor GenSci145. HWS116 shares its mechanism with bemarituzumab, the asset that Amgen acquired through its $1.9bn purchase of Five Prime Therapeutics. Bemarituzumab and HWS116 are among eight anti-FGFR2b MAbs still in development.

GeneScience describes GenSci145 as a novel mutation-selective PI3Kα inhibitor. This follows the entry in February 2026 of Cogent's H1047R mutation-specific CGT6297 into clinical trials.