Abstract PR013: First-in-human dose-expansion study of NBF-006, a novel investigational siRNA targeting GSTP, in patients with KRAS-mutated non-small cell lung cancer
Authors: Mamdani Hirva , Chiappori Alberto , Bazhenova Lyudmila , Spira Alexander , Iams Wade , Barve Minal , Tolcher Anthony W , Gabayan Eli , Vandross Andrae , Huynh Annie , Cohen-Arazi Yael , Albaugh Zachary , Gullbo Joachim , Zabludoff Sonya 
Published: December 2023

Background Glutathione S-transferase Pi (GSTP) has an important role in detoxification and anti-oxidative damage response. Additionally, GSTP has a chaperone function which regulates key oncogenic pathways such as the KRAS and JNK. Since alternative or redundant pathways could compensate for the inhibition of a single kinase, targeting multiple pathways could lead to more effective therapy. NBF-006 is a novel drug product comprised of GSTP siRNA encapsulated within a proprietary lipid nanoparticle. It is designed to deliver siRNA to localized and metastatic lung tumors. As GSTP downregulation leads to inhibition of KRAS signaling through modulation of both MAPK and PI3K pathways, NBF-006 is being developed to treat KRAS mutant tumors. NBF-006-001 is a first-in-man dose escalation (Part A) and expansion (Part B) study evaluating safety, tolerability, PK, and preliminary efficacy of NBF-006 administered intravenously over 70 minutes, QW4 followed by a 2-week rest period. Part A of the study enrolled 21 patients with advanced non-small cell lung cancer (NSCLC), pancreatic, or colorectal cancer. No DLTs or treatment-related SAEs were observed. NSCLC disease control rate of 55% (6/11) was observed in heavily pre-treated patient population, warranting further investigations. Results from advanced KRAS-mutated NSCLC patients enrolled in NBF-006-001 are reported here.

Results Thirty-four KRAS-mutated NSCLC patients received treatment at 0.6 mg/kg [n=12], 1.2 mg/kg [n=11], or 1.6 mg/kg [n=11]. NBF-006 was well tolerated with no treatment-related grade 4-5 AEs, SAEs, or DLTs. Two grade 3 events were assessed as possibly related to study treatment, anemia and bilateral pleural effusions (both at 0.6 mg/kg). The most common (&gt;10 % of patients) NBF-006-related AEs were Grade 1 or 2 infusion related reactions (low grade IRRs) (20.6 %) and nausea (11.8 %). There was no dose relationship in the number of AEs or any observed AEs. Low grade IRRs (n=8 in seven patients), occurred in the first cycle of therapy and were generally well-managed. Only one patient discontinued study therapy due to recurring IRR. Substantial cytokine elevation was only noted in this patient. No clinically meaningful complement activation nor ADA response has been observed. PK analysis indicated a mean terminal half-life of 41 (± 13) hours with no accumulation. Cmax and AUC demonstrated dose-proportionality up to 1.2 mg/kg and no apparent increase in exposure at 1.6 mg/kg. Patients had received 1-7 prior lines of therapy (average 2.6; 1 line [n=10], 2 lines [n=9], and ≥ 3 lines [n=15] respectively). Two patients (treated at 1.2 and 1.6 mg/kg) experienced a durable PR, 14 patients experienced SD. One patient with PR and one patient with a mixed response stayed on study for &gt;12 months.

Conclusion The expansion part of the NBF-006-001 study confirmed the favorable safety profile of NBF-006 and demonstrated early signs of antitumor activity in KRAS-mutated NSCLC. The results suggest that further clinical development of NBF-006, alone or in combination with standard therapy, is warranted.

Citation Format: Hirva Mamdani, Alberto Chiappori, Lyudmila Bazhenova, Alexander Spira, Wade Iams, Minal Barve, Anthony W Tolcher, Eli Gabayan, Andrae Vandross, Annie Huynh, Yael Cohen-Arazi, Zachary Albaugh, Joachim Gullbo, Sonya Zabludoff. First-in-human dose-expansion study of NBF-006, a novel investigational siRNA targeting GSTP, in patients with KRAS-mutated non-small cell lung cancer [abstract]. In: Proceedings of the AACR-NCI-EORTC Virtual International Conference on Molecular Targets and Cancer Therapeutics; 2023 Oct 11-15; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2023;22(12 Suppl):Abstract nr PR013.