3527 - Results of the Phase 2 TRAXAR Study: A Randomized Phase 2 Trial of Axitinib and TRC105 (TRAX) versus AXitinib (AX) Alone in Patients with Advanced or Metastatic Renal Cell Carcinoma (mRCC)

Background

Endoglin is an essential angiogenic receptor expressed on proliferating tumor vessels and RCC stem cells that is implicated as a mechanism of VEGF resistance. TRC105 is an endoglin monoclonal antibody that potentiates the anti-tumor activity of VEGF inhibitors in preclinical models and demonstrated a 29% RECIST response rate when combined with AX in patients with mRCC in a Phase 1b trial.

Methods

TRAXAR was a multicenter, randomized 1:1 (stratified by ECOG, 0 vs. 1), Phase 2 study of TRAX vs AX in patients with mRCC who had progressed following one prior VEGF inhibitor at 33 centers in the US and EU. The primary endpoint was progression-free survival (PFS) assessed by RECIST by independent review committee (IRC). Secondary endpoints included overall response rate (ORR), and safety. PFS and ORR were also assessed by Investigator review (INV) and according to Choi criteria (CC).

Results

Of 150 pts (TRAX, 75; AX, 75), 106 (71%) were male, 142 (95%) were white; median age was 64 years (range, 38-82). Treatment with TRAX did not prolong PFS compared to AX. ORR was not different based on IRC, INV or CC (Table). Most all-grade common adverse events (AEs) in TRAX vs AX: headache (65.8% vs. 16.2%), epistaxis (63.0% vs. 8.1%), and diarrhea (60.3% vs. 59.5%); most common serious AEs included: anemia (6.9% vs. 1.4%) and dehydration (4.1% vs. 0%).Table:

912PD

NE: not estimable; CI: confidence interval; mo: months

Conclusions

TRC105 did not demonstrate activity when combined with AX in patients with mRCC who had received prior VEGF inhibitor treatment, whether assessed using RECIST or Choi criteria. TRAX was generally well tolerated in pts with advanced or metastatic RCC.

Clinical trial identification

NCT01806064.

Editorial acknowledgement

Legal entity responsible for the study

TRACON Pharmaceuticals.

Funding

TRACON Pharmaceuticals.

Disclosure

T.K. Choueiri: Advisory / Consultancy, Research grant / Funding (institution), Travel / Accommodation / Expenses: TRACON; Honoraria (institution), Advisory / Consultancy, Research grant / Funding (institution): AstraZeneca; Honoraria (institution), Advisory / Consultancy, Research grant / Funding (institution): Bayer; Honoraria (institution), Advisory / Consultancy, Research grant / Funding (institution): BMS; Honoraria (institution), Advisory / Consultancy, Research grant / Funding (institution): Cerulean; Honoraria (institution), Advisory / Consultancy, Research grant / Funding (institution): Eisai; Honoraria (institution), Advisory / Consultancy, Research grant / Funding (institution): Foundation Medicine; Honoraria (institution), Advisory / Consultancy, Research grant / Funding (institution): Exelixis; Honoraria (institution), Advisory / Consultancy, Research grant / Funding (institution): Ipsen; Honoraria (institution), Advisory / Consultancy, Research grant / Funding (institution): Genentech; Honoraria (institution), Advisory / Consultancy, Research grant / Funding (institution): Roche; Honoraria (institution), Advisory / Consultancy, Research grant / Funding (institution): Roche Products Limited; Honoraria (institution), Advisory / Consultancy, Research grant / Funding (institution): GSM; Honoraria (institution), Advisory / Consultancy, Research grant / Funding (institution): Merck; Honoraria (institution), Advisory / Consultancy, Research grant / Funding (institution): Novartis; Honoraria (institution), Advisory / Consultancy, Research grant / Funding (institution): Peloton; Honoraria (institution), Advisory / Consultancy, Research grant / Funding (institution): Pfizer; Honoraria (institution), Advisory / Consultancy, Research grant / Funding (institution): Prometheus; Honoraria (institution), Advisory / Consultancy, Research grant / Funding (institution): Corvus; Honoraria (institution): Calithera. R.K. Pachynski: Advisory / Consultancy: EMD Serono; Advisory / Consultancy: Bristol-Myers Squibb; Advisory / Consultancy: Pfizer; Advisory / Consultancy, Speaker Bureau / Expert testimony: Sanofi; Advisory / Consultancy: Jounce Therapeutics; Speaker Bureau / Expert testimony: Dendreon; Speaker Bureau / Expert testimony: Merck; Speaker Bureau / Expert testimony, Travel / Accommodation / Expenses: Genentech/Roche; Speaker Bureau / Expert testimony: Genomic Health; Advisory / Consultancy: Bayer. Y. Zakharia: Advisory / Consultancy: Amgen; Advisory / Consultancy: Roche; Advisory / Consultancy: Novartis; Advisory / Consultancy: Jansen; Advisory / Consultancy: Eisai; Advisory / Consultancy: Exelixis; Advisory / Consultancy: Castle Bioscience; Advisory / Consultancy: Pfizer; Advisory / Consultancy: Array. T.H. Ho: Advisory / Consultancy: Roche; Advisory / Consultancy: Pfizer; Advisory / Consultancy: ipensenlivemeetings; Advisory / Consultancy: cardinal health; Advisory / Consultancy: Exelixis. B.E. Simpson: Shareholder / Stockholder / Stock options, Full / Part-time employment: TRACON Pharmaceuticals. B. Adams: Shareholder / Stockholder / Stock options, Full / Part-time employment: TRACON. L. Robertson: Shareholder / Stockholder / Stock options, Full / Part-time employment: TRACON. M. Darif: Advisory / Consultancy: TRACON. C. Theuer: Shareholder / Stockholder / Stock options, Full / Part-time employment, Officer / Board of Directors: TRACON. N. Agarwal: Advisory / Consultancy: Astellas; Advisory / Consultancy, Research grant / Funding (self): AstraZeneca; Advisory / Consultancy: Argos; Advisory / Consultancy: Bayer; Advisory / Consultancy: Clovis; Advisory / Consultancy, Research grant / Funding (self): Eisai; Advisory / Consultancy, Research grant / Funding (self): Exelixis; Advisory / Consultancy: EMD Serono; Advisory / Consultancy, Research grant / Funding (self): Ely Lilly; Advisory / Consultancy: Foundation One; Advisory / Consultancy: Genentech; Advisory / Consultancy, Research grant / Funding (self): Janssen; Advisory / Consultancy, Research grant / Funding (self): Merck; Advisory / Consultancy: Medivation; Advisory / Consultancy, Research grant / Funding (self): Novartis; Advisory / Consultancy: Nektar; Advisory / Consultancy, Research grant / Funding (self): Pfizer; Advisory / Consultancy: Pharmacyclics; Research grant / Funding (institution): Bavarian Nordic; Research grant / Funding (self): TRACON. All other authors have declared no conflicts of interest.