Biomedical subjects

Seock-Ah Im

Publications and source records attributed to Seock-Ah Im.

3 recordsLinked to original sources

PubMed2026

Pembrolizumab plus chemotherapy followed by pembrolizumab in participants in Asia with early triple-negative breast cancer: An updated subgroup analysis of the KEYNOTE-522 randomized clinical trial.

BACKGROUND: In KEYNOTE-522 (NCT03036488), addition of perioperative pembrolizumab to neoadjuvant chemotherapy significantly improved pathological complete response (pCR), event-free survival (EFS), and overall survival (OS) in early-stage triple-negative breast cancer (TNBC). pCR and EFS results in participants enrolled in Asia were consistent with those in the overall population. We report OS, updated EFS, and safety outcomes in participants enrolled in Asia. METHODS: Participants with newly diagnosed, high-risk, early-stage TNBC (T1c [N1‒N2] or T2‒T4 [N0‒N2] per AJCC 7th edition) were randomized 2:1 to 8 cycles of neoadjuvant pembrolizumab 200 mg Q3W or placebo plus chemotherapy. After definitive surgery, participants received adjuvant pembrolizumab 200 mg Q3W or placebo for ≤9 cycles. Primary endpoints were pCR (ypT0/Tis ypN0) and EFS. OS was a secondary endpoint. RESULTS: Of 1174 randomized participants, 216 were enrolled in Asia. At data cutoff (March 22, 2024), EFS events occurred in 18/136 participants (13.2%) in the pembrolizumab + chemotherapy group versus 22/80 (27.5%) in the placebo + chemotherapy group (HR, 0.43 [95% CI, 0.23‒0.81]); 60-month EFS rates (95% CIs) were 87.4% (80.6%‒92.0%) and 72.1% (60.7%‒80.6%), respectively. In the respective groups, 12/136 (8.8%) and 16/80 participants (20.0%) died (HR, 0.41 [95% CI, 0.19‒0.86]); 60-month OS rates (95% CIs) were 91.9% (85.8%‒95.4%) and 81.1% (70.5%‒88.1%). Treatment-related AEs led to treatment discontinuation in 19/136 participants (14.0%) with pembrolizumab + chemotherapy and 7/79 (8.9%) with placebo + chemotherapy. CONCLUSIONS: OS and updated EFS outcomes in KEYNOTE-522 participants enrolled in Asia were consistent with those in the overall population and support use of perioperative pembrolizumab + neoadjuvant chemotherapy as a standard-of-care treatment in this setting.

Adjuvant↗

PubMed2026

Clinical and Molecular Evaluation of HER2-Low and HER2-Ultralow Breast Cancer in the Penelope-B Clinical Trial Cohort.

The DestinyBreast (DB)04 and DB06 trials have shown clinical activity of trastuzumab-deruxtecan (T-DXd) in HER2-low and HER2-ultralow metastatic breast cancer. The identification of HER2-low and HER2-ultralow breast cancer is therefore essential for personalized therapy with T-DXd. We evaluated 723 residual tumors from the Penelope-B trial (NCT01864746) and correlated different levels of HER2 protein expression with prognosis and messenger RNA (mRNA) profiles, including HER2 transcripts. In Penelope-B, 57.68% (n = 417) of 723 residual tumors were HER2 low. The HER2-ultralow category was assigned to 109 (15.08%) tumors, and 197 (27.25%) tumors were completely HER2 negative (HER2 0). In Kaplan-Meier analysis, there were no survival differences among these 3 subgroups. There was no significant difference in HER2 mRNA expression between HER2-0 and HER2-ultralow tumors (P = .08). In contrast, there was a highly significant difference in HER2 mRNA expression between HER2-ultralow and HER2-low tumors (P < .0001) and between HER2-low and HER2-positive tumors (P < .0001). The extracellular protease cathepsin L, which has been suggested as a biomarker for extracellular cleavage of T-DXd, was detectable in all HER2-related subgroups and was a negative prognostic factor for invasive disease-free survival and overall survival (P = .0001) in preneoadjuvant core biopsies. In our study, we were able to characterize HER2 low as a clinically relevant and molecular defined tumor group with significantly increased HER2 expression. In contrast, for HER2 ultralow, we did not observe a defined molecular phenotype, despite the clinically relevant regulatory approval of T-DXd also in the ultralow subgroup. Additional investigations are needed to identify biomarkers beyond HER2 for T-DXd response as a basis for refined criteria for treatment eligibility.

Adult↗

PubMed2002

Decrease in apoptosis and increase in polyploidization of megakaryocytes by stem cell factor during ex vivo expansion of human cord blood CD34+ cells using thrombopoietin.

Thrombopoietin (TPO) is widely used for ex vivo expansion of hematopoietic stem cells. Previously, we have reported that TPO induces a characteristic pattern of apoptosis, and the TPO-induced apoptosis is closely associated with megakaryocyte (MK) differentiation. In the present study, several cytokines, flt3-ligand, stem cell factor (SCF), interleukin-3 (IL-3), IL-6, IL-11, leukemia inhibitory factor, G-CSF, and erythropoietin, which are known to affect megakaryocytopoiesis, have been evaluated to elucidate their effects on the TPO-induced apoptosis. Measurement of apoptosis by flow cytometry revealed that only SCF absolutely reduced the TPO-induced apoptosis in MK fractions, particularly in the late phase of ex vivo expansion. Platelet production was demonstrated by electron microscopy in a later phase when SCF was added. Simultaneous measurement of DNA contents with immunophenotyping demonstrated a significant increase in polyploidization in the CD41+ cell fraction when cultured with SCF. These results suggested that SCF not only inhibited premature senescence but also enhanced maturation of the differentiating cells of MK lineage during ex vivo expansion using TPO.

Antigens, CD34↗