4762 - A Phase 1a/2b Trial of the CXCR4 Inhibitor X4P-001 and Nivolumab for Advanced Renal Cell Carcinoma (RCC) that is Unresponsive to Nivolumab Monotherapy

Background

X4P-001 is an oral, selective, allosteric, CXCR4 inhibitor. In melanoma patients (pts), single agent X4P-001 increased tumor inflammatory signature and antigen presentation/processing gene expression scores in the tumor microenvironment (TME) and promoted activated, cytotoxic T cell infiltration. It is hypothesized that X4P-001 has the ability to restore immunity within the TME and potentially enhance the antitumor activity of checkpoint inhibitors.

Methods

This is an open-label study to evaluate the safety and clinical activity of X4P001 in combination with nivolumab for advanced RCC. Pts receiving standard-of-care nivolumab monotherapy who had a best response of stable disease (SD) or progressive disease (PD) received 400 mg QD of X4P-001 while continuing 240 mg IV nivolumab infusions every 2 weeks. Blood and serum biomarkers were also assessed.

Results

Of 9 enrolled pts (8 males/1 female; median age, 65 years), 1 remains on study and 8 have discontinued due to PD (4 pts), or treatment-related adverse events (AEs, 4 pts). Drugrelated AEs (≥ 25%) were diarrhea (5 pts); nasal congestion (4 pts); dry eye and alanine aminotransferase increase (3 pts each). Grade ≥ 3 drug-related AEs of autoimmune hepatitis; mucosal inflammation; rash; and increased lipase, alanine and aspartate aminotransferase were reported in 1 pt each. The best responses observed were partial response (PR; n = 1), SD (SD; n = 7), and PD (n = 1). Of the 5 pts with SD on earlier nivolumab monotherapy, 1 had a subsequent confirmed PR, and all 4 pts with PD on monotherapy at study entry had SD with the X4P-001 combination (median duration: 6.5 months; range: 3.7-10.6). Cytokine/chemokine concentrations in pt serum, pre- and post-combination treatment, will be presented.

Conclusions

X4P-001 and nivolumab combination therapy in advanced RCC pts demonstrated potential antitumor activity and a manageable safety profile. These results, together with previously presented data from our melanoma study, suggest that CXCR4 inhibition mediated by X4P-001 may synergize with PD-1 blockade to enhance antitumor immune responses in pts that fail to respond to checkpoint inhibitor therapy alone.

Clinical trial identification

NCT02923531.

Legal entity responsible for the study

X4 Pharmaceuticals.

Funding

X4 Pharmaceuticals.

Editorial Acknowledgement

Timothy Henion; Acumen Medical Communications.

Disclosure

E. Tsiroyannis, K. Niland, Y. Wang, S. Parasuraman, L. Gan: Employee: X4 Pharmaceuticals. All other authors have declared no conflicts of interest.