Analysis of Adverse Events Associated with Trastuzumab Deruxtecan in Patients with Gastric and Breast Cancer: A Retrospective Study.

Trastuzumab deruxtecan (T-DXd) has displayed demonstrable efficacy and manageable toxicity in previously treated patients with advanced gastric and breast cancer, and it has been approved in Japan. However, there is a lack of data on the optimal management in clinical practice. Therefore, we assessed the adverse event (AE) profiles of T-DXd in patients with advanced gastric or breast cancer to provide guidance for appropriate management. This retrospective study was conducted at the Cancer Institute Hospital of the Japanese Foundation for Cancer Research. We reviewed the medical records of patients with advanced gastric or breast cancer who received T-DXd between May 2020 and December 2021. AEs occurring within the first three cycles of T-DXd were evaluated according to Common Terminology Criteria for Adverse Events version 5.0. Thirty-six patients were enrolled (gastric: n = 19, breast: n = 17). All 15 males had gastric cancer, whereas 4 and 17 females had gastric and breast cancer, respectively. Interstitial lung disease (ILD) occurred in five patients (14%), but no patients had severe ILD. Gastrointestinal (GI) toxicities, including nausea (61%), vomiting (22%), decreased appetite (33%), and diarrhea (39%), were the most common AEs. The incidence of GI toxicities did not differ by cancer type; however, nausea was significantly more common in females (81 vs. 33%; p < 0.01). T-DXd was safely administered in clinical practice in patients with previously treated advanced gastric or breast cancer. The management of GI toxicities is important in the clinical implementation of T-DXd.

Novel pharmacological effects of poly (ADP-ribose) polymerase inhibitor rucaparib on the lactate dehydrogenase pathway.

Poly (ADP-ribose) polymerases (PARPs) are involved in various cellular events, including DNA repair. PARP inhibitors including olaparib and rucaparib, have been specially developed against breast and ovarian cancers deficient in DNA repair systems. In this study, we found that PARP1-defective olaparib-resistant A2780 cells (ola-R cells) cells were still sensitive to two PARP inhibitors, rucaparib and veliparib. Metabolomic analysis revealed that rucaparib suppressed the lactate dehydrogenase (LDH)-mediated conversion of pyruvic acid to lactic acid in A2780 cells, although olaparib did not. The inhibition of LDH by siRNA-mediated knockdown or by LDH inhibitors suppressed the growth of ovarian cancer cells. Our results suggested that the suppression of the LDH-associated pathway contributed to the pharmacological effects of rucaparib.

Regorafenib-Induced Hand-Foot Skin Reaction Is More Severe on the Feet Than on the Hands.

Regorafenib is a multikinase inhibitor for the treatment of metastatic colorectal cancer. Regorafenib-induced hand-foot skin reaction (HFSR) is a common side effect during treatment. The reported frequency of HFSR was 80% (grade 3: 28%) in the Japanese subpopulation in the CORRECT trial; however, more detailed data regarding HFSR in terms of onset and sites of susceptibility are unclear. Additionally, the risk factors for regorafenib-induced severe HFSR are unknown. The aim of this study was to compare HFSR between the hands and feet and identify preexisting risk factors for severe HFSR in Japanese patients receiving regorafenib. We retrospectively examined the onset and severity of HFSR on the hands and feet of patients with metastatic colorectal cancer treated with regorafenib from May 2013 to October 2015 in the Cancer Institute Hospital of the Japanese Foundation for Cancer Research. In addition, we examined the possible association between preexisting clinical factors and severe HFSR. Our results showed that no significant difference in the incidence of HFSR of any grade was observed between the hands (71%) and feet (74%) (p = 0.63). The incidence of grade 3 HFSR was more frequent on the feet (33%) than on the hands (8%) (p < 0.01). The onset of grade 3 HFSR was earlier on the feet than on the hands (p < 0.001). No preexisting risk factor was identified. Our findings indicate that severe HFSR was more prevalent on the feet than on the hands, suggesting the need for appropriate screening for early detection and treatment of regorafenib-induced HSFR.

Functional Effects of AKT3 on Aurora Kinase Inhibitor-induced Aneuploidy.

The suppression of mitotic Aurora kinases (AURKs) by AURK inhibitors frequently causes cytokinetic failure, leading to polyploidy or aneuploidy, indicating the critical role of AURK-mediated phosphorylation during cytokinesis. We demonstrate the deregulated expression of AKT3 in Aurora kinase inhibitor (AURKi)-resistant cells, which we established from human colorectal cancer HCT 116 cells. The AKT family, which includes AKT1, -2, and -3, plays multiple roles in antiapoptotic functions and drug resistance and is involved in cell growth and survival pathways. We found that an AKT inhibitor, AZD5363, showed synergistic effect with an AURKi, VX-680, on two AKT3-expressing AURKi-resistant cell lines, and AKT3 knockdown sensitized cells to VX-680. Consistent with these activities, AKT3 expression suppressed AURKi-induced apoptosis and conferred resistance to AURKi. Thus, AKT3 expression affects cell sensitivity to AURKi. Moreover, we found that AKT3 expression suppressed AURKi-induced aneuploidy, and inversely AKT3 knockdown enhanced it. In addition, partial co-localization of AKT3 with AURKB was observed during anaphase. Overall, this study suggests that AKT3 could repress the antiproliferative effects of AURKi, with a novel activity particularly suppressing the aneuploidy induction.

Effect of AKT3 expression on MYC- and caspase-8-dependent apoptosis caused by polo-like kinase inhibitors in HCT 116 cells.

Polo-like kinase (PLK) is a cell-cycle regulator that is overexpressed in several cancer cell types. Polo-like kinase is considered a novel target for cancer therapies, and several PLK inhibitors (PLKis), including BI 2536, BI 6727, and GSK461364, have been developed. In this study, we established five BI 2536-resistant cell lines from human colorectal cancer HCT 116 cells, to explore the resistance mechanism and identify predictable biomarkers of PLKis. We showed that PLKi-induced caspase-8 activation was attenuated in the BI 2536-resistant cell lines. We also showed that the expression of P-glycoprotein (P-GP) and AKT3 was upregulated, whereas that of MYC was downregulated in some BI 2536-resistant cell lines. Expression of P-GP conferred resistance to PLKis, and PLKi-induced apoptosis was dependent on MYC and caspase-8 in HCT 116 cells. We also showed for the first time that AKT3 suppressed BI 6727-induced caspase-8 activation and conferred resistance to PLKis. Collectively, these results indicate that MYC, caspase-8, P-GP, and AKT3 play critical roles in PLKi-induced apoptosis. Therefore, they are candidate biomarkers of the pharmacological efficacy of PLKis.