Exploratory composite endpoint demonstrates benefit of trilaciclib across multiple clinically meaningful components of myeloprotection in patients with small cell lung cancer

Big Decisions on Small Cell Lung Cancer: A Focus on Clinical Care Updates and Patient Perspectives

Small cell lung cancer (SCLC) is an uncommon, aggressive high-grade neuroendocrine carcinoma, associated with tobacco use. It is a highly chemosensitive disease that initially responds quickly to systemic therapy, although patients with SCLC tend to develop relapse. Although the landscape of SCLC treatment has remained stagnant for many decades, the field has seen notable advances in the past few years, including the use of immunotherapy, the development of further lines of systemic therapy, the refinement of thoracic and intracranial radiotherapy, and-most recently-the promise of more targeted therapies. Patients with SCLC also must face unique psychosocial burdens in their experience with their cancer, distinct from patients with other lung cancer. In this article, we review the latest literature and future directions in the management and investigation of SCLC, as well as the critical decisions that providers and patients must navigate in the current landscape. We also present the perspectives of several patients with SCLC in conjunction with this summary, to spotlight their individual journeys in the context of this challenging disease.

Trilaciclib dosage in Chinese patients with extensive-stage small cell lung cancer: a pooled pharmacometrics analysis

This study aimed to analyze potential ethnic disparities in the dose-exposure-response relationships of trilaciclib, a first-in-class intravenous cyclin-dependent kinase 4/6 inhibitor for treating chemotherapy-induced myelosuppression in patients with extensive-stage small cell lung cancer (ES-SCLC). This investigation focused on characterizing these relationships in both Chinese and non-Chinese patients to further refine the dosing regimen for trilaciclib in Chinese patients with ES-SCLC. Population pharmacokinetic (PopPK) and exposure-response (E-R) analyses were conducted using pooled data from four randomized phase 2/3 trials involving Chinese and non-Chinese patients with ES-SCLC. PopPK analysis revealed that trilaciclib clearance in Chinese patients was approximately 17% higher than that in non-Chinese patients with ES-SCLC. Sex and body surface area influenced trilaciclib pharmacokinetics in both populations but did not exert a significant clinical impact. E-R analysis demonstrated that trilaciclib exposure increased with a dosage escalation from 200 to 280 mg/m2, without notable changes in myeloprotective or antitumor efficacy. However, the incidence of infusion site reactions, headaches, and phlebitis/thrombophlebitis rose with increasing trilaciclib exposure in both Chinese and non-Chinese patients with ES-SCLC. These findings suggest no substantial ethnic disparities in the dose-exposure-response relationship between Chinese and non-Chinese patients. They support the adoption of a 240-mg/m2 intravenous 3-day or 5-day dosing regimen for trilaciclib in Chinese patients with ES-SCLC.

Trilaciclib: A Novel Approach to Mitigate Chemotherapy-Induced Myelosuppression in Cancer Treatment

Trilaciclib, a novel cyclin-dependent kinase 4/6 inhibitor, has demonstrated the ability to protect bone marrow from chemotherapy toxicity, improving patients' quality of life (QoL). This review describes the mechanism of action, efficacy, and toxicity profile of trilaciclib. Trilaciclib halts retinoblastoma protein phosphorylation during the early G1 phase, preventing the transition from the G1/S phase and inducing the cell cycle arrest in the G1 phase, which protects the hematopoietic cell lineages. Trilaciclib is indicated by the United States Food and Drug Administration and National Comprehensive Cancer Network to decrease the incidence of chemotherapy-induced myelosuppression in adult patients before a platinum/etoposide or topotecan containing regimen for extensive stage small cell lung cancer. Its ease of administration as an intravenous infusion, given before starting chemotherapy, and the favorable side effect profile make it a better-tolerated drug, improving patient QoL.

Systemic Therapy for Small-Cell Lung Cancer: ASCO-Ontario Health (Cancer Care Ontario) Guideline

PURPOSE

To provide evidence-based recommendations to practicing clinicians on the management of patients with small-cell lung cancer.

METHODS

An Expert Panel of medical oncology, thoracic surgery, radiation oncology, pulmonary, community oncology, research methodology, and advocacy experts were convened to conduct a literature search, which included systematic reviews, meta-analyses, and randomized controlled trials published from 1990 through 2022. Outcomes of interest included response rates, overall survival, disease-free survival or recurrence-free survival, and quality of life. Expert Panel members used available evidence and informal consensus to develop evidence-based guideline recommendations.

RESULTS

The literature search identified 95 relevant studies to inform the evidence base for this guideline.

RECOMMENDATIONS

Evidence-based recommendations were developed to address systemic therapy options, timing of therapy, treatment in patients who are older or with poor performance status, role of biomarkers, and use of myeloid-supporting agents in patients with small-cell lung cancer.Additional information is available at www.asco.org/thoracic-cancer-guidelines.

Quinazolinone derivatives as new potential CDK4/6 inhibitors, apoptosis inducers and radiosensitizers for breast cancer

Background: Targeting CDK4/6 has advanced breast cancer treatment. Herein, new quinazolinones were synthesized with acetamide linkers as potential anti-breast cancer agents. Methods & results: In vitro cytotoxic evaluation on human breast cancer cell lines (MCF7 and MDA-MB-231) identified 1,3-benzodioxole (5d) to be of the highest potency. It showed good inhibitory activity on CDK4/6. Compound 5d arrested the cell cycle at the G1-phase, caused induction of early and late apoptosis in an Annexin V-FITC assay, led to an increase in the level of caspase-3 and upregulated Bax expression and downregulated Bcl-2 in MCF7 cells. Compound 5d showed good radiosensitizing activity when combined with a single dose of 8-Gy γ-radiation. Conclusion: This study introduces quinazolinone scaffolds as new CDK4/6 inhibitors for breast cancer.

The efficacy and safety of Trilaciclib in preventing chemotherapy-induced myelosuppression: a systematic review and meta-analysis of randomized controlled trials

Background: This study aims to assess the clinical efficacy and safety of Trilaciclib in preventing chemotherapy-induced myelosuppression in adult patients through meta-analysis. Methods: The PubMed, Embase, Cochrane Library, Clinical Trials, EU Clinical Trials Register, and International Clinical Trials Registry Platform were searched up to 25 October 2022. Only randomized controlled trials (RCTs) comparing the clinical outcomes of Trilaciclib and Trilaciclib plus chemotherapy for treating malignant cancers in adult patients were included. The primary outcome included the incidence of SN, FN, the DSN, and administration of ESAs, G-CSFs, and RBC or platelet transfusions, while the secondary outcomes included the risk of adverse events (AEs) and severe adverse events (SAEs). Results: In total, four randomized controlled trials (RCTs) involving 345 patients with SCLC or breast cancer were included in this meta-analysis. Results showed that administration of Trilaciclib significantly reduced the occurrence of SN (19.3% vs. 42.2%, OR = 0.31), FN (3.22% vs. 6.72%, OR = 0.47), anemia (20.5% vs. 38.2%, OR = 0.38) and shortened the DSN during treatment. The proportion of patients receiving therapeutic use of ESAs (4.03% vs. 11.8%, OR = 0.31), G-CSF (37.0% vs. 53.5%, OR = 0.52), RBC transfusions (19.8% vs. 29.9%, OR = 0.56) was also statistically lower in the experimental group than in the control group. Meanwhile, the ORR, overall survival, and progress-free survival of the two groups were identical, and no negative impact of Trilaciclib on the clinical outcomes of chemotherapy treatments was found. Other chemotherapy-induced adverse events (AEs) and severe adverse events (SAEs) like diarrhea, fatigue, nausea, and vomiting were identical regardless of Trilaciclib usage. Conclusion: Trilaciclib demonstrated its efficacy in reducing the occurrence of chemotherapy-induced myelosuppression and utilization of supportive care interventions without undermining the clinical benefits of chemotherapy regimens during treatment with an acceptable safety profile.

Selective protection of normal cells from chemotherapy, while killing drug-resistant cancer cells

Cancer therapy is limited by toxicity in normal cells and drug-resistance in cancer cells. Paradoxically, cancer resistance to certain therapies can be exploited for protection of normal cells, simultaneously enabling the selective killing of resistant cancer cells by using antagonistic drug combinations, which include cytotoxic and protective drugs. Depending on the mechanisms of drug-resistance in cancer cells, the protection of normal cells can be achieved with inhibitors of CDK4/6, caspases, Mdm2, mTOR, and mitogenic kinases. When normal cells are protected, the selectivity and potency of multi-drug combinations can be further enhanced by adding synergistic drugs, in theory, eliminating the deadliest cancer clones with minimal side effects. I also discuss how the recent success of Trilaciclib may foster similar approaches into clinical practice, how to mitigate systemic side effects of chemotherapy in patients with brain tumors and how to ensure that protective drugs would only protect normal cells (not cancer cells) in a particular patient.

Grade 4 Neutropenia Frequency as a Binary Risk Predictor for Adverse Clinical Consequences of Chemotherapy‑Induced Neutropenia: A Meta-analysis

Neutropenia is the major toxicity of myelosuppressive cancer chemotherapy. Grade 4 neutropenia (Gr4N) is a measure of chemotherapy-induced neutropenia (CIN) severity. We conducted a meta-analysis of CIN data. Gr4N incidence was significantly correlated with febrile neutropenia (FN), days of severe neutropenia (DSN), and nadir absolute neutrophil count (ANC), which are all important predictors of morbidity. With a Gr4N threshold of 65%, both FN and DSN were below levels for low risk of adverse CIN outcomes. Gr4N was highly predictive for adverse CIN outcomes, and a 65% threshold demarcated low vs. high risk for FN and other adverse CIN outcomes.

Non-canonical approaches to targeting hypoxic tumors

Hypoxia is a common characteristic in solid cancers. Hypoxia-inducible factors (HIFs) are involved in various aspects of cancer, such as angiogenesis, metastasis and therapy resistance. Targeting the HIF pathway has been regarded as a challenging but promising strategy in cancer treatment with recent FDA approval of a HIF2α-inhibitor. During the past several decades, numerous efforts have been made to understand how HIFs participate in cancer development and progression along with how HIF signaling can be modulated to achieve anti-cancer effect. In this chapter, we will provide an overview of the role of hypoxia and HIFs in cancer, summarize the oxygen-dependent and independent mechanisms of HIF-1α regulation, and discuss emerging approaches targeting hypoxia and HIF signaling which possess therapeutic potential in cancer. We will emphasize on two signaling pathways, involving cyclin-dependent kinases (CDKs) and heat shock protein 90 (HSP90), which contribute to HIF-1α (and HIF-2α) stabilization in an oxygen-independent manner. Through reviewing their participation in malignant progression and the potential targeting strategies, we discuss the non-canonical approaches to target HIF signaling in cancer therapy.

Targeting the epigenetic processes to enhance antitumor immunity in small cell lung cancer

Dysregulation of the epigenetic processes, such as DNA methylation, histone modifications, and modulation of chromatin states, drives aberrant transcription that promotes initiation and progression of small cell lung cancer (SCLC). Accumulating evidence has proven crucial roles of epigenetic machinery in modulating immune cell functions and antitumor immune response. Epigenetics-targeting drugs such as DNA methyltransferase inhibitors, histone deacetylase inhibitors, and histone methyltransferase inhibitors involved in preclinical and clinical trials may trigger antitumor immunity. Herein, we summarize the impact of epigenetic processes on tumor immunogenicity and antitumor immune cell functions in SCLC. Furthermore, we review current clinical trials of epigenetic therapy against SCLC and the mechanisms of epigenetic inhibitors to boost antitumor immunity. Eventually, we discuss the opportunities of developing therapeutic regimens combining epigenetic agents with immunotherapy for SCLC.

Design, synthesis and biological evaluation of pteridine-7(8H)-one derivatives as potent and selective CDK4/6 inhibitors

Cyclin-dependent kinases play an important role in the regulation of cell cycle and transcription. Selective CDK4/6 inhibitors have been demonstrated to be effective in the treatment of cancer. In this article, we described the design and synthesis of a series of pteridine-7(8H)-one derivatives as dual CDK4/6 inhibitors. Among them, the most promising compound L2 exhibited significant inhibitory activity against CDK4 and CDK6 with IC₅₀ values of 16.7 nM and 30.5 nM respectively and showed excellent selectivity to CDK1/2/7/9. Moreover, compound L2 displayed potent antiproliferative activities at low digital micromolar range via inducing apoptosis in breast and colon cancer cells. In all, we developed a new series of pteridine-7(8H)-one derivatives which exhibited promising antitumor activities as selective CDK4/6 inhibitors.