Fluorescence-guided tumor detection with a novel anti-EpCAM targeted antibody fragment: Preclinical validation.

Tumor-specific fluorescent imaging agents are moving towards the clinic, supporting surgeons with real-time intraoperative feedback about tumor locations. The epithelial cell adhesion molecule (EpCAM) is considered as one of the most promising tumor-specific proteins due its high overexpression on epithelial-derived cancers. This study describes the development and evaluation of EpCAM-F800, a novel fluorescent anti-EpCAM antibody fragment, for intraoperative tumor imaging.

DeBouganin Diabody Fusion Protein Overcomes Drug Resistance to ADCs Comprised of Anti-Microtubule Agents.

Antibody drug conjugates (ADC), comprised of highly potent small molecule payloads chemically conjugated to a full-length antibody, represent a growing class of therapeutic agents. The targeting of cytotoxic payloads via the specificity and selectivity of the antibody has led to substantial clinical benefits. However, ADC potency can be altered by mechanisms of resistance such as overexpression of efflux pumps or anti-apoptotic proteins.

Trastuzumab-deBouganin Conjugate Overcomes Multiple Mechanisms of T-DM1 Drug Resistance.

The development of antibody drug conjugates has provided enhanced potency to tumor-targeting antibodies by the addition of highly potent payloads. In the case of trastuzumab-DM1 (T-DM1), approved for the treatment of metastatic breast cancer, the addition of mertansine (DM1) to trastuzumab substantially increased progression-free survival. Despite these improvements, most patients eventually relapse due to complex mechanisms of resistance often associated with small molecule chemotherapeutics.

A phase II study of oportuzumab monatox: an immunotoxin therapy for patients with noninvasive urothelial carcinoma in situ previously treated with bacillus Calmette-Guérin.

Purpose: A phase II study was performed to assess the efficacy and tolerability of intravesical oportuzumab monatox in patients with urothelial carcinoma in situ of the bladder. Bacillus Calmette-Guérin treatment had previously failed in all patients.

Materials And Methods: A total of 46 patients received 1 induction cycle of 6 (cohort 1) or 12 (cohort 2) weekly intravesical oportuzumab monatox (VB4-845) instillations of 30 mg, followed by up to 3 maintenance cycles of 3 weekly administrations every 3 months.

Preclinical evaluation of VB6-845: an anti-EpCAM immunotoxin with reduced immunogenic potential.

VB6-845 is a recombinant immunotoxin comprised of deBouganin (a de-immunized plant toxin) genetically linked to an epithelial cell adhesion molecule (EpCAM)-targeting humanized Fab fragment (4D5MOCB). EpCAM is highly expressed on a wide range of epithelial tumors but has limited expression on most normal epithelia and therefore represents an excellent target for immunotherapy. A comprehensive preclinical evaluation was performed to determine the safety and suitability of VB6-845 as a systemically administered drug for the treatment of solid tumors.

Development of a GMP Phase III purification process for VB4-845, an immunotoxin expressed in E. coli using high cell density fermentation.

VB4-845 is a recombinant immunotoxin comprised of an anti-epithelial cell adhesion molecule (EpCAM) scFv fused to a truncated form of the bacterial toxin, Pseudomonas exotoxin A. VB4-845, purified from TB fed-batch fermentation, showed clinical efficacy when administered locally to treat non-muscle invasive bladder cancer (NMIBC) and squamous cell carcinomas of the head and neck (SCCHN). Here, we describe the implementation of an Escherichia coli high cell density (HCD) cultivation and purification process for VB4-845.

A Phase I study of an intravesically administered immunotoxin targeting EpCAM for the treatment of nonmuscle-invasive bladder cancer in BCGrefractory and BCG-intolerant patients.

Purpose: A Phase I dose-escalation study was performed to determine the maximum tolerated dose (MTD) of the immunotoxin VB4-845 in patients with nonmuscle-invasive bladder cancer (NMIBC) refractory to or intolerant of bacillus Calmette-Guerin (BCG). Secondary objectives included evaluation of the safety, tolerability, pharmacokinetics, immunogenicity, and efficacy of VB4-845.

Patients And Methods: Sixty-four patients with Grade 2 or 3, stage Ta or T1 transitional cell carcinoma or in situ carcinoma, either refractory to or intolerant of BCG therapy, were enrolled.

Fusogenics: a recombinant immunotoxin-based screening platform to select internalizing tumor-specific antibody fragments.

Antibody-based therapeutics play a vital role in the treatment of certain cancers; however, despite commercial success, various strategies are being pursued to increase their potency and hence improve patient outcomes. The use of antibodies to deliver a cytotoxic payload offers a promising alternative for more efficacious therapies. Immunotoxins are composed of an internalizing antibody fragment linked to a bacterial or plant toxin.

A phase I clinical study of VB4-845: weekly intratumoral administration of an anti-EpCAM recombinant fusion protein in patients with squamous cell carcinoma of the head and neck.

VB4-845 is a scFv-Pseudomonas exotoxin A fusion construct that targets epithelial cell adhesion molecule (EpCAM). A phase I trial was conducted to determine the maximum tolerated dose (MTD) of VB4-845 when administered as weekly intratumoral (IT) injections to patients with squamous cell carcinoma of the head and neck (SCCHN). Secondary objectives included the evaluation of the safety, tolerability, pharmacokinetic profile, and immunogenicity, and a preliminary assessment of tumor response.

Preclinical assessment of an anti-EpCAM immunotoxin: locoregional delivery provides a safer alternative to systemic administration.

VB4-845 is a recombinant immunotoxin that is comprised of a truncated form of Pseudomonas exotoxin A (ETA) genetically-linked to a humanized scFv fragment, (4D5MOCB), specific to epithelial cell adhesion molecule (EpCAM). EpCAM is overexpressed on a wide variety of human tumors and thus represents a suitable target antigen for immunotoxin therapy. Preclinical studies were used to evaluate the benefit of locoregional administration of an ETA-based immunotoxin versus systemic delivery.

Engineering and biological characterization of VB6-845, an anti-EpCAM immunotoxin containing a T-cell epitope-depleted variant of the plant toxin bouganin.

The clinical development of immunotoxins in the treatment of solid tumors has been impeded in part, by the induction of an immune response directed primarily against the toxin moiety. Bouganin, a type I ribosome inactivating protein isolated from the leaf of Bougainvillea spectabilis Willd, was mutated to remove the T-cell epitopes while preserving the biological activity of the wild-type molecule. The T-cell epitope-depleted variant of bouganin (de-bouganin) was genetically linked to an anti-epithelial cell adhesion molecule (EpCAM) Fab moiety via a peptidic linker containing a furin proteolytic site to create the fusion construct VB6-845.

StARD13(Dlc-2) RhoGap mediates ceramide activation of phosphatidylglycerolphosphate synthase and drug response in Chinese hamster ovary cells.

To identify genes involved in etoposide drug response, we used promoter trap mutagenesis to isolate an etoposide-resistant Chinese hamster ovary (CHO) cell line. This resistant CHO-K1 line, named E91, showed cross-resistance to C(2)-ceramide (N-acetylsphingosine). The promoter trap retrovirus was found integrated into intron 1-2 of the Dlc-2 (Stard13) RhoGap gene.

Hypoxia induces autophagic cell death in apoptosis-competent cells through a mechanism involving BNIP3.

Hypoxia (lack of oxygen) is a physiological stress often associated with solid tumors. Hypoxia correlates with poor prognosis since hypoxic regions within tumors are considered apoptosisresistant. Autophagy (cellular "self digestion") has been associated with hypoxia during cardiac ischemia and metabolic stress as a survival mechanism.

BNIP3 plays a role in hypoxic cell death in human epithelial cells that is inhibited by growth factors EGF and IGF.

Hypoxic regions within solid tumors are often resistant to chemotherapy and radiation. BNIP3 (Bcl-2/E1B 19 kDa interacting protein) is a proapoptotic member of the Bcl-2 family that is expressed in hypoxic regions of tumors. During hypoxia, BNIP3 expression is increased in many cell types and upon forced overexpression BNIP3 induces cell death.