Kathleen Wortham

Targeting the Lymphotoxin-β Receptor with Agonist Antibodies as a Potential Cancer Therapy

The lymphotoxin-beta receptor (LT beta R) is a tumor necrosis factor receptor family member critical for the development and maintenance of various lymphoid microenvironments. Herein, we show that agonistic anti-LT beta R monoclonal antibody (mAb) CBE11 inhibited tumor growth in xenograft models and potentiated tumor responses to chemotherapeutic agents. In a syngeneic colon carcinoma tumor model, treatment of the tumor-bearing mice with an agonistic antibody against murine LT beta R caused increased lymphocyte infiltration and necrosis of the tumor. A pattern of differential gene expression predictive of cellular and xenograft response to LT beta R activation was identified in a panel of colon carcinoma cell lines and when applied to a panel of clinical colorectal tumor samples indicated 35% likelihood a tumor response to CBE11. Consistent with this estimate, CBE11 decreased tumor size and/or improved long-term animal survival with two of six independent orthotopic xenografts prepared from surgical colorectal carcinoma samples. Targeting of LT beta R with agonistic mAbs offers a novel approach to the treatment of colorectal and potentially other types of cancers.

Development of an Fn14 agonistic antibody as an anti-tumor agent

TWEAK, a TNF family ligand with pleiotropic cellular functions, was originally described as capable of inducing tumor cell death in vitro. TWEAK functions by binding its receptor, Fn14, which is up-regulated on many human solid tumors. Herein, we show that intratumoral administration of TWEAK, delivered either by an adenoviral vector or in an immunoglobulin Fc-fusion form, results in significant inhibition of tumor growth in a breast xenograft model. To exploit the TWEAK-Fn14 pathway as a therapeutic target in oncology, we developed an anti-Fn14 agonistic antibody, BIIB036. Studies described herein show that BIIB036 binds specifically to Fn14 but not other members of the TNF receptor family, induces Fn14 signaling, and promotes tumor cell apoptosis in vitro. In vivo, BIIB036 effectively inhibits growth of tumors in multiple xenograft models, including colon (WiDr), breast (MDA-MB-231), and gastric (NCI-N87) tumors, regardless of tumor cell growth inhibition response observed to BIIB036 in vitro. The anti-tumor activity in these cell lines is not TNF-dependent. Increasing the antigen-binding valency of BIB036 significantly enhances its anti-tumor effect, suggesting the contribution of higher order cross-linking of the Fn14 receptor. Full Fc effector function is required for maximal activity of BIIB036 in vivo, likely due to the cross-linking effect and/or ADCC mediated tumor killing activity. Taken together, the anti-tumor properties of BIIB036 validate Fn14 as a promising target in oncology and demonstrate its potential therapeutic utility in multiple solid tumor indications.

Stable IgG-like Bispecific Antibodies Directed toward the Type I Insulin-like Growth Factor Receptor Demonstrate Enhanced Ligand Blockade and Anti-tumor Activity

Bispecific antibodies (BsAbs) target multiple epitopes on the same molecular target or different targets. Although interest in BsAbs has persisted for decades, production of stable and active BsAbs has hindered their clinical evaluation. Here, we describe the production and characterization of tetravalent IgG-like BsAbs that combine the activities of allosteric and competitive inhibitors of the type-I insulin-like growth factor receptor (IGF-1R). The BsAbs, which were engineered for thermal stability, express well, demonstrate favorable biophysical properties, and recognize both epitopes on IGF-1R. Only one BsAb with a unique geometry, denoted BIIB4-5scFv, was capable of engaging all four of its binding arms simultaneously. All the BsAbs (especially BIIB4-5scFv) demonstrated enhanced ligand blocking over the single monoclonal antibodies (mAbs), particularly at high ligand concentrations. The pharmacokinetic profiles of two IgG-like BsAbs were tested in nude mice and shown to be comparable with that of the parental mAbs. The BsAbs, especially BIIB4-5scFv, demonstrated an improved ability to reduce the growth of multiple tumor cell lines and to inhibit ligand-induced IGF-1R signaling in tumor cells over the parental mAbs. BIIB4-5scFv also led to superior tumor growth inhibition over its parental mAbs in vivo. In summary, BsAbs that bridge multiple inhibitory mechanisms against a single target may generally represent a more effective strategy for intervention in oncology or other indications compared with traditional mAb therapy.

The anti-Fn14 antibody BIIB036 inhibits tumor growth in xenografts and patient derived primary tumor models and enhances efficacy of chemotherapeutic agents in multiple xenograft models.

Agonistic antibodies targeting Fn14, the receptor for TWEAK, have demonstrated anti-tumor activity in xenograft models. Herein, we further explore the therapeutic potential of the humanized anti-Fn14 agonistic antibody, BIIB036, as a single agent and in combination with standard of care cancer therapeutics. Pharmacokinetic studies of BIIB036 in tumor-bearing mice revealed a half-life of approximately three days suggesting twice a week dosing would be necessary to maintain efficacy. However, in multiple xenograft models, BIIB036 treatment resulted in extended tumor growth inhibition up to 40–50 d following cessation of dosing, suggesting that frequent administration of BIIB036 may not be necessary to maintain prolonged anti-tumor activity. Subsequent xenograft studies revealed that maximal efficacy was achieved with BIIB036 dosing once every two weeks, by either intraperitoneal or subcutaneous administration. Xenograft tumors that were initially treated with BIBI036 and then re-grew up to 1000 mm3 following cessation of the first cycle of treatment remained sensitive to a second cycle of treatment. BIIB036 was also evaluated in patient derived primary colon tumor models, where efficacy compared favorably with a standard of care agent. Lastly, BIIB036 enhanced the efficacy of several standard of care chemotherapeutics, including paclitaxel in MDA-MBA-231 breast tumor xenografts, paclitaxel or carboplatin in HOP62 non-small cell lung xenografts, and 5-FU in NCI-N87 gastric xenografts, with no overlapping toxicities. These studies thus establish BIIB036 as a promising therapeutic agent with durable anti-tumor activity in human xenografts as well as patient derived primary tumor models, and enhanced activity and tolerability in combination with standard of care chemotherapeutics. Taken together, the data presented herein suggest that BIIB036 warrants evaluation in the clinic.

Protective Effect of Tonapofylline (BG9928), an Adenosine A1 Receptor Antagonist, against Cisplatin-Induced Acute Kidney Injury in Rats

Background/Aims: Cisplatin (CIS) induces nephrotoxicity partly through renal vasoconstriction and decreased glomerular filtration effects thought to involve adenosine acting on adenosine A1 receptors (A1Rs). We studied the effect of the orally active, A1R antagonist tonapofylline (BG9928) on biochemical measures of renal function in CIS-induced acute kidney injury (AKI) in rats. Methods: Tonapofylline, 1 mg/kg b.i.d., p.o., was administered on days 0–1 or 0–6 to rats treated with CIS 5.5 mg/kg i.v. Prednisolone (PRED) 5 mg/kg s.c. (day 0) served as a positive control. Serum creatinine and urea nitrogen (BUN) were measured in serial blood samples taken over the 13-day study period. Results: CIS produced significant elevations in creatinine, reduction in body weight and marked proximal tubular injury throughout the renal cortex and outer medulla. Tonapofylline, days 0–1 or 0–6 and PRED all produced sustained reductions in post-CIS serum creatinine and BUN levels compared with controls, improved body weight recovery and significant attenuation of CIS-induced kidney pathology scores. Conclusion: These data support the involvement of A1Rs in CIS-induced AKI in rats. Tonapofylline may be useful in the clinical setting for the prevention of kidney failure induced by nephrotoxic agents such as CIS.

Consultants for the American Journal of Nephrology 2009

Glenn Chertow Robert Chevalier Monique Cho Kai-Ming Chow Felix Claverie-Martin Mark Cooper Fernando Cordido Daniel Coyne Farhad Danesh Robert Danziger John Daugirdas Prasad Devarajan Francis Dumler Thomas Easterling Tevfik Ecder Paul Eggers Randa El Zein Kathrin Eller Murray Epstein Sahar Fathallah-Shaykh Gal Finer Jeffrey Fink Michael Fischer Agnes Fogo Barry Freedman Eli Friedman Verica Garaj-Vrhovac Richard Glassock Glenda Gobe Stuart Goldstein Harvest Gu Krishnamurthy Gudehithlu Martha Gulati Michael Haase Melisha Hanna Peter Hart Kitamura Harumi Marion Hofmann-Bowman Yao Huang Adrian Iaina Narita Ichiei Zaid Abassi Kevin Abbott Rajiv Agarwal Adesuyi Ajayi Charambolos Antoniades Natarajan Aravindan Gema Ariceta Jose Arruda Arif Asif John Asplin Jonas Axelsson Mindy Banks Vinod Bansal Amy Barton Pai David Basile Alexei Basnakian Srinivasan Beddhu Enrico Benedetti Carsten Bergmann Daniel Berlowitz Judith Beto Rajendra Bhimma Erhard Bieberich Geoffrey Block Amy Bobrowski Neil Boudville Michael Braun Carolyn Brecklin Ellen Brooks Rebecca Brown Steve Brunelli Nigel Brunskill Emmanuel Burdmann Michel Burnier Hui Cai David Calhoun Niels Camara Vito Campese Thomas Carpenter Tak Mao Chan Arelene Chapman