Kelun-Biotech to Present Two Abstracts for SKB264 (MK-2870) at AACR Annual Meeting

The 2024 American Association for Cancer Research (AACR) Annual Meeting will be held in San Diego, California from April 5-10th.

Sichuan Kelun-Biotech Biopharmaceutical Co., Ltd. (6990.HK, the “Company”) will present the results of two clinical studies of anti-TROP2 ADC sacituzumab tirumotecan (sac-TMT, formerly SKB264/MK-2870) during the AACR Annual Meeting. The abstracts for the studies have been published on the AACR official website as of April 5th, 2024.

1. The updated efficacy and safety results for anti-TROP2 ADC SKB264/sac-TMT in patients with previously treated advanced non-small cell lung cancer (NSCLC) from a phase 2 study will be presented in a poster session scheduled on April 9th, 2024, from 1:30 PM - 5:00 PM local time (Abstract Presentation Number: CT247).

2. The preliminary efficacy and safety results for anti-TROP2 ADC SKB264/sac-TMT in patients with previously treated advanced gastric or gastroesophageal junction (GEJ) cancer from a phase 2 study will be presented in an oral presentation, which is scheduled on April 9th, 2024 from 2:30 PM - 4:30 PM local time (Abstract Presentation Number: CT038).

The study results are summarized as follows:

SKB264/sac-TMT in NSCLC:

Patients with previously treated advanced NSCLC were enrolled to receive SKB264/sac-TMT at 5 mg/kg Q2W until disease progression or unacceptable toxicity (KL264-01, NCT04152499). The data cut-off date was November 22, 2023.

Five Phase 3 global studies of SKB264/sac-TMT in patients with NSCLC are ongoing. Including two Phase 3 global studies of SKB264/sac-TMT in patients with 3L+ EGFR mutant NSCLC (NCT06074588), and 2L EGFR mutant NSCLC (NCT06305754) and a Phase 3 study ofSKB264/sac-TMT in China in patients with 2L EGFR mutant NSCLC (NCT05870319). Additionally two Phase 3 global studies of SKB264/sac-TMT plus pembrolizumab in patients with metastatic NSCLC expressing programmed death ligand 1 (PD-L1)≥ 50% (NCT06170788) and resectable NSCLC not achieving pathological complete response (NCT06312137) are ongoing.

As of the Data Cut-off date, 43 NSCLC patients had been enrolled and the median follow-up was 17.2 months. 21 patients with EGFR wild type had received a median of 3 prior regimens of therapy including anti-PD-1/L1 inhibitors. 22 patients with EGFR mutant had progressed on or after TKI therapy, 50% of whom also failed at least one line of chemotherapy. Updated efficacy results are shown in the following:

*Including confirmed or unconfirmed response. Based on response evaluable patients (≥1 on-study scans) with 4 patients (2 EGFR mutant patients with non-squamous histology and 2 EGFR wild type patients with squamous histology) excluded.

The most common Grade ≥3 treatment-related adverse events (TRAEs) were neutrophil count decreased (34.9%), anemia (30.2%), white blood cell (WBC) count decreased (25.6%), stomatitis (9.3%), and rash (7.0%). No TRAEs leading to treatment discontinuation or deaths occurred. No drug-related interstitial lung disease (ILD)/pneumonitis was reported.

SKB264/sac-TMT in Gastric/GEJ cancer:

Patients with previously treated inoperable advanced gastric/GEJ adenocarcinoma were enrolled to receive SKB264/sac-TMT monotherapy at 5 mg/kg Q2W until disease progression or unacceptable toxicity in Phase 2 expansion cohort of KL264-01 study (NCT04152499). Patients with heavily pre-treated gastric/GEJ cancer were enrolled first, and then the cohort was amended to enroll patients with only one prior therapy of chemotherapy and anti-PD-1/L1 therapy. The data cut-off date was Nov 22, 2023.

As of the data cut-off date, a total of 48 patients were enrolled and followed up for at least 9 weeks. 24 patients (50.0%) had received one prior line of therapy (2L), while 24 patients (50.0%) had received ≥ 2 prior lines of therapy (3L+). 40 patients (83.3%) had received prior anti-PD-1/L1 inhibitors. Of 41 response-evaluable patients (defined as ≥ 1 on-study scans), the objective response rate (ORR) was 22.0% (9 partial responses, 2 pending confirmation) and disease control rate (DCR) was 80.5%. The ORRs in the 2L and 3L+ setting were 27.3% (including 2 pending confirmation) and 15.8%, respectively. Median duration of response (DoR) was 7.5 months. In the subset of 3L+ patients (n=24 including 54.2% of patients with ≥ 4 prior lines of therapy) with more mature follow-up (median follow up of 14.6 months), the median progression free survival (mPFS) was 3.7 months (95% CI: 2.6, 5.4) and median overall survival (mOS) was 7.6 months (95% CI: 5.3, 15.5).

The most common ≥ Grade 3 TRAEs were anemia (20.8%), neutrophil count decreased (18.8%), WBC decreased (12.5%) and neutropenia (6.3%). No TRAEs leading to treatment discontinuation or deaths occurred. No neuropathy or drug-related ILD/pneumonitis was reported.

A Phase 3 global study of SKB264/sac-TMT monotherapy versus standard of care (SOC) chemotherapy in 3L+ gastric/GEJ adenocarcinoma is being planned.