Name: Emiltatug ledadotin (Emi-Le) in Adenoid cystic carcinoma with solid histology or high-grade transformation: Generic, brand name and therapeutic class of product
Published: 2026-09-17T22:01:26-04:00

Manufacturer: Servier

“Servier today announced that the U.S. Food and Drug Administration (FDA) has granted breakthrough therapy designation to Emi-Le” (opens the source at this quote in a new tab)

“Servier today announced promising new Phase 1 clinical data for Emi-Le, an investigational antibody drug conjugate (ADC) directed against B7-H4” (opens the source at this quote in a new tab)

Nonproprietary name and development codes

“Emiltatug ledadotin (Emi-Le; DAY501 or XMT-1660) is a B7-H4-directed ADC with a site-specific conjugated auristatin F-HPA microtubule inhibitor payload at a homogenous DAR6 via a fully synthetic linker framework using the GlycoConnect® technology.” (opens the source at this quote in a new tab)

“The company also announced that the World Health Organization has approved emiltatug ledadotin (abbreviated as Emi-Le) as XMT-1660’s international nonproprietary name (INN).” (opens the source at this quote in a new tab)

Brand name

No evidence found.

Therapeutic class

“Emi-Le (XMT-1660) is a B7-H4-directed ADC with an auristatin F-HPA microtubule inhibitor payload.” (opens the source at this quote in a new tab)

Originator: Mersana Therapeutics

“Our two clinical-stage product candidates are emiltatug ledadotin (XMT-1660), which we refer to as Emi-Le, and XMT-2056. Emi-Le is a B7-H4-targeting Dolasynthen ADC designed with a precise, target-optimized DAR of 6 that we are investigating in a Phase 1 clinical trial that is currently enrolling patients with various tumors, including breast, endometrial and ovarian cancers, as well as adenoid cystic carcinoma type 1, or ACC-1.” (opens the source at this quote in a new tab)

Acquisition of Mersana Therapeutics by Day One Biopharmaceuticals

“Mersana Therapeutics, Inc. (Nasdaq: MRSN), a clinical-stage biopharmaceutical company focused on the development of antibody-drug conjugates (ADCs) targeting cancers in areas of high unmet medical need, today announced that it has entered into a definitive merger agreement with Day One Biopharmaceuticals (“Day One”), pursuant to which Day One would acquire Mersana, through a tender offer followed by a second step merger” (opens the source at this quote in a new tab)

“All of the conditions of the tender offer having been satisfied, Day One accepted for payment all such tendered shares, and following a statutory merger under Section 251(h) of the Delaware General Corporation Law on January 6, 2026, Mersana became a direct wholly owned subsidiary of Day One.” (opens the source at this quote in a new tab)
“Through this acquisition, Day One has added a second novel ADC to the company’s clinical pipeline.” (opens the source at this quote in a new tab)

Acquisition of Day One Biopharmaceuticals by Servier

“Servier, an independent international pharmaceutical group governed by a foundation, today announced the successful completion of the tender offer to acquire all of the issued and outstanding shares of common stock of Day One Biopharmaceuticals, Inc. (Nasdaq: DAWN) (“Day One”), a biopharmaceutical company dedicated to developing and commercializing targeted therapies for people of all ages with life-threatening diseases, for $21.50 per share.” (opens the source at this quote in a new tab)
“In addition to tovorafenib, which is being investigated in additional indications, Day One’s pipeline includes Emi-Le (emiltatug ledadotin), a novel antibody drug conjugate (ADC) and DAY301, a targeted therapy in rare cancers.” (opens the source at this quote in a new tab)

Current trial sponsor

Field	Quoted record
Lead sponsor	“Day One Biopharmaceuticals, Inc.”
Organization study ID	“MER-XMT-1660-1”

Manufacturing

“We do not own or operate and currently have no plans to establish any current good manufacturing practices, or cGMP, compliant manufacturing facilities. We currently rely, and expect to continue to rely, on external Contract Manufacturing Organizations, or CMOs, for the manufacture of product to support our activities through regulatory approval and commercial manufacturing, as well as to support our manufacturing obligations under our current collaborations.” (opens the source at this quote in a new tab)