3 research outputs found
Site-Specific Tandem Knoevenagel Condensation–Michael Addition To Generate Antibody–Drug Conjugates
Expanded
ligation techniques are sorely needed to generate unique linkages
for the growing field of functionally enhanced proteins. To address
this need, we present a unique chemical ligation that involves the
double addition of a pyrazolone moiety with an aldehyde-labeled protein.
This ligation occurs via a tandem Knoevenagel condensation–Michael
addition. A pyrazolone reacts with an aldehyde to generate an enone,
which undergoes subsequent attack by a second pyrazolone to generate
a bis-pyrazolone species. This rapid and facile ligation technique
is performed under mild conditions in the absence of catalyst to generate
new architectures that were previously inaccessible via conventional
ligation reactions. Using this unique ligation, we generated three
site-specifically labeled antibody–drug conjugates (ADCs) with
an average of four drugs to one antibody. The in vitro and in vivo
efficacies along with pharmacokinetic data of the site-specific ADCs
are reported
Aldehyde Tag Coupled with HIPS Chemistry Enables the Production of ADCs Conjugated Site-Specifically to Different Antibody Regions with Distinct in Vivo Efficacy and PK Outcomes
It is becoming increasingly clear
that site-specific conjugation
offers significant advantages over conventional conjugation chemistries
used to make antibody–drug conjugates (ADCs). Site-specific
payload placement allows for control over both the drug-to-antibody
ratio (DAR) and the conjugation site, both of which play an important
role in governing the pharmacokinetics (PK), disposition, and efficacy
of the ADC. In addition to the DAR and site of conjugation, linker
composition also plays an important role in the properties of an ADC.
We have previously reported a novel site-specific conjugation platform
comprising linker payloads designed to selectively react with site-specifically
engineered aldehyde tags on an antibody backbone. This chemistry results
in a stable C–C bond between the antibody and the cytotoxin
payload, providing a uniquely stable connection with respect to the
other linker chemistries used to generate ADCs. The flexibility and
versatility of the aldehyde tag conjugation platform has enabled us
to undertake a systematic evaluation of the impact of conjugation
site and linker composition on ADC properties. Here, we describe the
production and characterization of a panel of ADCs bearing the aldehyde
tag at different locations on an IgG1 backbone conjugated using Hydrazino-<i>iso</i>-Pictet-Spengler (HIPS) chemistry. We demonstrate that
in a panel of ADCs with aldehyde tags at different locations, the
site of conjugation has a dramatic impact on in vivo efficacy and
pharmacokinetic behavior in rodents; this advantage translates to
an improved safety profile in rats as compared to a conventional lysine
conjugate
Discovery of (<i>R</i>)‑4-Cyclopropyl-7,8-difluoro-5-(4-(trifluoromethyl)phenylsulfonyl)-4,5-dihydro‑1<i>H</i>‑pyrazolo[4,3‑<i>c</i>]quinoline (ELND006) and (<i>R</i>)‑4-Cyclopropyl-8-fluoro-5-(6-(trifluoromethyl)pyridin-3-ylsulfonyl)-4,5-dihydro‑2<i>H</i>‑pyrazolo[4,3‑<i>c</i>]quinoline (ELND007): Metabolically Stable γ‑Secretase Inhibitors that Selectively Inhibit the Production of Amyloid‑β over Notch
Herein,
we describe our strategy to design metabolically stable γ-secretase
inhibitors which are selective for inhibition of Aβ generation
over Notch. We highlight our synthetic strategy to incorporate diversity
and chirality. Compounds <b>30</b> (ELND006) and <b>34</b> (ELND007) both entered human clinical trials. The in vitro and in
vivo characteristics for these two compounds are described. A comparison
of inhibition of Aβ generation in vivo between <b>30</b>, <b>34</b>, Semagacestat <b>41</b>, Begacestat <b>42</b>, and Avagacestat <b>43</b> in mice is made. <b>30</b> lowered Aβ in the CSF of healthy human volunteers