422 An open-label, multicenter, phase 1/2 clinical trial of RP1, an enhanced potency oncolytic HSV, combined with nivolumab: updated results from the skin cancer cohorts

Mark Middleton, Francesca Aroldi, Joseph Sacco, Mohammed Milhem, Brendan Curti, Ari VanderWalde MBioeth, Scott Baum, Adel Samson, Anna Pavlick, Jason Chesney, Jiaxin Niu, Terence Rhodes, Tawnya Bowles, Robert Conry, Anna Olsson-Brown, Douglas Earl Laux, Howard Kaufman, Praveen Bommareddy, Alex Deterding, Selda SamakogluRobert Coffin, Kevin Harrington

Research output: Other contribution

Abstract

Background RP1 is an enhanced potency oncolytic HSV encoding a fusogenic protein (GALV-GP R-) and GM-CSF which has previously demonstrated tolerable safety and tumor regression alone and with nivolumab in patients with a number of tumor types. Updated data from the phase 1 expansion with nivolumab, melanoma phase 2 (enrollment complete) and non-melanoma skin cancer (NMSC; enrollment ongoing) cohorts will be presented (NCT03767348). Enrollment of a further 125 patient anti-PD1 refractory cutaneous melanoma cohort; and activation of a cohort of anti-PD1 refractory NSCLC is underway.

Methods Stage IIIb-IV melanoma patients for whom anti-PD-1 was indicated or who were refractory to prior anti-PD-1 alone or in combination with anti-CTLA-4, were enrolled. NMSC patients were anti-PD1 naïve. Patients received ≤8 doses of RP1 (≤10 mL/visit Q2W; first dose 106 PFU/mL then 107 PFU/mL) with nivolumab (240 mg IV Q2W for 4 months then 480 mg IV Q4W up to 2 years) from the second RP1 dose.

Results As of 24th June 2020, 36 melanoma and 16 NMSC patients had been enrolled with follow up of 8 weeks follow up, one of two angiosarcoma patients and seven of eight CSCC patients (5 CR) have achieved response (CSCC ORR 87.5%; CR rate 62.5%, including of uninjected visceral disease). Tumor biopsies in patients continue to routinely show immune activation, including robust recruitment of CD8+ T cells, reversal of T cell exclusion, and increased PD-L1 expression. Treatment remains ongoing, and current data will be presented.

Conclusions RP1 and nivolumab have continued to be well tolerated, with continued promising anti-tumor activity in patients with skin cancers, including those with anti-PD1 refractory and other difficult to treat melanomas, and in patients with CSCC.

http://dx.doi.org/10.1136/jitc-2020-SITC2020.0422

Original languageUndefined/Unknown
StatePublished - Nov 9 2020

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NameArticles, Abstracts, and Reports

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