On April 17, 2023 Avistone Biotechnology ("Avistone" or "the Company"), a clinical-stage biotechnology company focused on precision oncology therapeutics, reported interim results from its ongoing phase 1 study on PLB1004 (Press release, Avistone Pharmaceuticals, APR 17, 2023, View Source [SID1234630212]). The data were presented today (CT102) at the American Association for Cancer Research (AACR) (Free AACR Whitepaper) Annual Meeting 2023 in Orlando, Florida USA.

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PLB1004, a novel mono-anilino-pyrimidine small molecule inhibitor of EGFR, potently and irreversibly targets exon 20 insertion. The molecule also potently targets classical EGFR mutations ExDel19, L858R and T790M with a high degree of selectivity over wild-type EGFR.

The study is a multi-center, open-label, dose escalation and expansion study conducted entirely in China, to assess the safety, tolerability, pharmacokinetics, and anti-tumor effect of PLB1004, administered orally, in patients with advanced non-small cell lung cancer. The primary objective of the study is to assess the safety profile of PLB1004 and determine the RP2D of the molecule.

At the cutoff date for these interim results, July 31, 2022, a total of 65 patients (32 in escalation and 33 in expansion) had received treatment with PLB1004. Dose escalation ranged from a starting dose of 10 mg QD to a top dose of 480 mg QD in 11 cohorts of patients. As of July 31, 2022, dose expansion occurred at two dose levels, 320 mg QD and 400 mg QD. The median age of the patients is 58 years old (range 31 to 77). Most patients are women (60%) with adenocarcinoma (95%) and good performance status (ECOG 0-1 in 98%). The most frequent treatment related adverse events included diarrhea in 75% of patients (19% Grade 3), rash in 60% of patients (11% Grade 3), mouth ulceration in 43% of patients (1.5% Grade 3), elevated serum creatinine in 43% of patients (2% Grade 3) and elevated aspartate aminotransferase in 41% of patients (3% Grade 3). No DLTs were observed at any dose level and thus an MTD was not determined during cycle 1 of drug administration. Beyond Cycle 1, at the highest dose levels, frequent dose interruptions and reductions due to toxicity were observed, and further dose escalation was not attempted above 480 mg QD. Across all dose groups, a total of 38 subjects had EGFR Ex20ins mutations, including 29 at doses ≥ 160 mg QD, among whom 26 completed at least 1 tumor assessment. In these 26 patients the confirmed best response rate was 57.7% (15/26) and the disease control rate (DCR) was 100% (26/26). Among the 26 patients (≥160mg QD dose level) with EGFR Ex20ins mutation who completed at least one tumor evaluation, 8 patients had brain metastases, and 3 of them had a PR (37.5%).

"PLB1004 appears to be safe and well-tolerated with promising anti-tumor activity in patients with NSCLC harboring EGFR exon 20 insertion mutations," said Jin-Ji Yang, M.D., Primary Investigator from Guangdong Provincial People’s Hospital.

"Avistone is a science-driven, innovative biotechnology company committed to the discovery and clinical development of first-in-class and best-in-class drugs," said Dr. Hepeng Shi, Chairman, CEO, and Founder of Avistone. "We are proud to share data at this year’s AACR (Free AACR Whitepaper) conference for PLB1004 which has best-in-class potential for patients with EGFR NSCLC. We are excited to present these additional data and to highlight the advancements we are achieving for patients with lung cancer."

Electronic copies of the poster presented at the AACR (Free AACR Whitepaper) annual meeting are available upon request.