Byondis

aka Synthon Biopharmaceuticals, Byondis B.V.

Byondis is a Dutch antibody-drug conjugate company, formerly Synthon Biopharmaceuticals, whose HER2 conjugate trastuzumab duocarmazine improved progression-free survival in the TULIP trial but did not win US approval.

Byondis develops antibody-drug conjugates with its duocarmycin-based ByonZine linker-drug technology and the ByonShieLD site-specific conjugation platform. Trastuzumab duocarmazine (SYD985) links trastuzumab to a DNA-alkylating duocarmazine prodrug; in the phase 3 TULIP trial in pretreated HER2-positive metastatic breast cancer it lengthened progression-free survival over physician's choice, but the FDA issued a complete response letter in 2023 and the European application was withdrawn. Byondis continues with next-generation conjugates.

Headquarters

Nijmegen, NL

Scorecard

All companies

#436of 1181 companies, score 5

targets +2
modalities +2
registry trials +4
failures -3

0 approved, 0 in phase 3, 0 earlier, 1 targets, 4 registry studies. Formula on the scorecards page.

Type

biotech

Website

www.byondis.com/

Products

1top

WithdrawnADC

Trastuzumab duocarmazine

A HER2 ADC with a DNA-alkylating payload that beat chemotherapy in a phase 3 trial yet never reached the market, because eye and lung toxicity and a stronger rival arrived first.

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