Background: RX-0201, a novel, oligonucleotide that binds native AKT-1 mRNA, prevents downstream phosphorylation to p-AKT. RX-0201, in combination with everolimus, additively inhibited Caki-1 cell growth in vitro and is in development for the treatment of metastatic clear cell renal carcinoma

Methods: The phase Ib/II proof of concept, multicenter, open label study is conducted in 2 phases. The phase Ib was a dose-escalation study of RX-0201 administered in combination with everolimus. RX-0201 was administered as a continuous intravenous infusion for 14 days followed by 7 days of rest; everolimus was administered at a starting dose of 10mg once daily. Subjects were enrolled at increasing doses of RX-0201 in a modified 3+3 design. Plasma concentrations were measured in phase Ib and noncompartmental pharmacokinetic parameters were calculated using WinNonlin, Version 6.4. The dose of RX-0201 identified in phase Ib is being studied further in phase II, which is the randomized, 2-arm study of RX-0201 in combination with everolimus versus everolimus alone.

Results: In the Phase Ib, seven males and 3 females, (median age 61 years) were treated with 125 mg/m⁁2/day (n = 3), 200 mg/m⁁2/day (n = 4), and 250 mg/m⁁2/day (n = 3) RX-0201 in combination with 10 mg everolimus. They received 1-3 lines of therapy prior to study entry (median = 1). The most common toxicities attributed to the combination were rash, mouth ulceration, weight loss, thrombocytopenia, facial edema, fatigue, and pruritus. No significant events were attributed to RX-0201 alone. Most events (81%) were mild or moderate in severity. Based on the tolerability, 250 mg/m⁁2/day RX-0201 dose was declared the recommended phase II dose. Three subjects in the phase Ib have experienced stable disease for 383, 191, and 122 days; a tumor burden reduction of 16 and 36% was seen in 2 subjects. RX-0201 PK demonstrated a dose proportional exposure.

Conclusions: RX-0201, in combination with everolimus, appears to be safe and well tolerated in patients with metastatic renal cancer at doses up to 250 mg/m⁁2/day. Randomized phase II of this trial is currently ongoing.

Citation Format: Scott Tagawa, Gurkamal S. Chatta, Sumanta K. Pal, Sanjay Goel, Reza Mazhari, Callie Heaton, Ely Benaim, Neeraj Agarwal. Phase Ib/II Study of RX-0201, a novel AKT-1 antisense, combined with everolimus to treat metastatic clear cell renal carcinoma - Phase Ib results. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr CT114.