Design and Synthesis of Tesirine, a Clinical Antibody–Drug Conjugate Pyrrolobenzodiazepine Dimer Payload

Pyrrolobenzodiazepine dimers are an emerging class of warhead in the field of antibody–drug conjugates (ADCs). Tesirine (SG3249) was designed to combine potent antitumor activity with desirable physicochemical properties such as favorable hydrophobicity and improved conjugation characteristics. One of the reactive imines was capped with a cathepsin B-cleavable valine-alanine linker. A robust synthetic route was developed to allow the production of tesirine on clinical scale, employing a flexible, convergent strategy. Tesirine was evaluated in vitro both in stochastic and engineered ADC constructs and was confirmed as a potent and versatile payload. The conjugation of tesirine to anti-DLL3 rovalpituzumab has resulted in rovalpituzumab-tesirine (Rova-T), currently under evaluation for the treatment of small cell lung cancer.
https://cdn-pubs.acs.org/doi/suppl/10.1021/acsmedchemlett.6b00062/suppl_file/ml6b00062_si_001.pdf
SG3249 (tesirine) (860 mg, 73% over 2 steps). LC/MS, method 2, 2.65 min (ES+) m/z (relative intensity) 1496.78 ([M+H] +. , 20). [] 24 D = +262 (c = 0.056, CHCl3).
1H NMR (400 MHz, DMSO-d6) δ 9.95 (s, 1H), 8.20 (d, J = 7.0 Hz, 1H), 8.03 (t, J = 5.6 Hz, 1H), 7.97 – 7.84 (m, 2H), 7.55 (d, J = 8.1 Hz, 2H), 7.32 (s, 1H), 7.18 (d, J = 8.0 Hz, 2H), 7.10 – 6.96 (m, 3H), 6.84 (s, 1H), 6.79 – 6.57 (m, 4H), 5.59 (d, J = 9.4 Hz, 1H), 5.16 (d, J = 12.7 Hz, 1H), 4.81 (d, J = 12.4 Hz, 1H), 4.38 (t, J = 7.1 Hz, 1H), 4.32 – 4.17 (m, 2H), 4.17 – 4.07 (m, 1H), 4.07 – 3.87 (m, 3H), 3.80 (d, J = 14.2 Hz, 6H), 3.74 – 3.62 (m, 1H), 3.59 (t, J = 7.2 Hz, 4H), 3.55 – 3.42 (m, 28H), 3.35 (d, J = 5.2 Hz, 2H), 3.21 – 3.11 (m, 2H), 3.11 – 2.98 (m, 2H), 2.98 – 2.83 (m, 1H), 2.49 – 2.28 (m, 5H), 2.03 – 1.88 (m, 1H), 1.87 – 1.65 (m, 10H), 1.64 – 1.47 (m, 2H), 1.29 (t, J = 5.9 Hz, 3H), 0.85 (dd, J = 17.1, 6.7 Hz, 6H).
13C NMR (126 MHz, DMSO-d6) δ 171.55, 171.29, 171.16, 170.78, 169.91, 164.80, 162.52, 155.03, 150.25, 139.27, 134.99, 128.84, 123.13, 122.67, 121.76, 119.28, 111.93, 110.93, 86.05, 70.21, 70.16, 70.02, 69.95, 69.46, 68.93, 68.79, 67.39, 57.94, 56.16, 54.03, 49.49, 38.97, 38.89, 36.39, 34.53, 34.40, 31.04, 28.69, 28.65, 22.72, 19.60, 18.55, 18.37, 13.88, 13.82. HRMS (ESI) m/z Calc. C75H101N9O23 1495.70831 found 1495.70444.
FT-IR (ATR, cm‐1 ) 3311, 2911, 2871, 1706, 1643, 1623, 1601, 1512, 1435, 1411, 1243, 1213, 1094, 1075, 946, 827, 747, 695, 664.




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DRUG APPROVALS BY DR ANTHONY MELVIN CRASTO
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