Effects of Trilaciclib on Chemotherapy-Induced Myelosuppression and Patient-Reported Outcomes in Patients with Extensive-Stage Small Cell Lung Cancer: Pooled Results from Three Phase II Randomized, Double-Blind, Placebo-Controlled Studies

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.

Effect of Hepatic Impairment on Trilaciclib Pharmacokinetics

Trilaciclib is a first-in-class, intravenous cyclin-dependent kinase 4 and 6 inhibitor approved for reducing the incidence of chemotherapy-induced myelosuppression in adult patients with extensive-stage small cell lung cancer receiving a platinum/etoposide-containing or topotecan-containing regimen. No dose adjustment is recommended for participants with mild hepatic impairment (HI) based on previous population pharmacokinetic (PK) analysis. This open-label, parallel-group study examined the impact of moderate and severe HI on the PK of trilaciclib. The study employed a reduced study design. Participants with moderate (Child-Pugh B, n = 8) and severe (Child-Pugh C, n = 5) HI and matched healthy controls (n = 11) received a single intravenous dose of trilaciclib 100 mg/m2. The unbound fraction of trilaciclib was comparable between the HI groups and the matched healthy control group. The unbound trilaciclib extent of exposure (i.e., area under the concentration-time curve) in participants with moderate and severe HI was ∼40% and ∼60% higher, respectively, compared with healthy matched controls based on Child-Pugh classification. Ad hoc analysis using National Cancer Institute classification showed similar results. The US Food and Drug Administration-approved trilaciclib dose of 240 mg/m2 should be reduced by ∼30%, to 170 mg/m2, for patients with moderate or severe HI.

The impact of myelosuppression on quality of life of patients treated with chemotherapy

Side effects from chemotherapy-induced myelosuppression can negatively affect patients' quality of life (QoL). Neutropenia increases infection risk, and anemia frequently results in debilitating fatigue. Additionally, the bleeding risk associated with thrombocytopenia can lead to fear and anxiety. However, traditional interventions for myelosuppression fall short of the ideal. Granulocyte colony-stimulating factors reduce the risk of severe neutropenia but commonly lead to bone pain. Erythropoiesis-stimulating agents are not always effective and may cause thromboembolic events, while transfusions to correct anemia/thrombocytopenia are associated with transfusion reactions and volume overload. Trilaciclib, which is approved for reducing myelosuppression in patients with extensive-stage small cell lung cancer, together with several investigational agents in development for managing myelosuppression have the potential to improve QoL for patients on chemotherapy.

Small molecule agents for triple negative breast cancer: Current status and future prospects

Triple-negative breast cancer (TNBC) is a subtype of breast cancer with poor prognosis. The number of cases increased by 2.26 million in 2020, making it the most commonly diagnosed cancer type in the world. TNBCs lack hormone receptor (HR) and human epidermal growth factor 2 (HER2), which limits treatment options. Currently, paclitaxel-based drugs combined with other chemotherapeutics remain the main treatment for TNBC. There is currently no consensus on the best therapeutic regimen for TNBC. However, there have been successful clinical trials exploring large-molecule monoclonal antibodies, small-molecule targeted drugs, and novel antibody-drug conjugate (ADC). Although monoclonal antibodies have produced clinical success, their large molecular weight can limit therapeutic benefits. It is worth noting that in the past 30 years, the FDA has approved small molecule drugs for HER2-positive breast cancers. The lack of effective targets and the occurrence of drug resistance pose significant challenges in the treatment of TNBC. To improve the prognosis of TNBC, it is crucial to search for effective targets and to overcome drug resistance. This review examines the clinical efficacy, adverse effects, resistance mechanisms, and potential solutions of targeted small molecule drugs in both monotherapies and combination therapies. New therapeutic targets, including nuclear export protein 1 (XPO1) and hedgehog (Hh), are emerging as potential options for researchers and become integrated into clinical trials for TNBC. Additionally, there is growing interest in the potential of targeted protein degradation chimeras (PROTACs), degraders of rogue proteins, as a future therapy direction. This review provides potentially valuable insights with clinical implications.

Promises of Protein Kinase Inhibitors in Recalcitrant Small-Cell Lung Cancer: Recent Scenario and Future Possibilities

SCLC is refractory to conventional therapies; targeted therapies and immunological checkpoint inhibitor (ICI) molecules have prolonged survival only marginally. In addition, ICIs help only a subgroup of SCLC patients. Different types of kinases play pivotal roles in therapeutics-driven cellular functions. Therefore, there is a significant need to understand the roles of kinases in regulating therapeutic responses, acknowledge the existing knowledge gaps, and discuss future directions for improved therapeutics for recalcitrant SCLC. Here, we extensively review the effect of dysregulated kinases in SCLC. We further discuss the pharmacological inhibitors of kinases used in targeted therapies for recalcitrant SCLC. We also describe the role of kinases in the ICI-mediated activation of antitumor immune responses. Finally, we summarize the clinical trials evaluating the potential of kinase inhibitors and ICIs. This review overviews dysregulated kinases in SCLC and summarizes their potential as targeted therapeutic agents. We also discuss their clinical efficacy in enhancing anticancer responses mediated by ICIs.

Phase I/II Study of the WEE1 Inhibitor Adavosertib (AZD1775) in Combination with Carboplatin in Children with Advanced Malignancies: Arm C of the AcSé-ESMART Trial

PURPOSE

AcSé-ESMART Arm C aimed to define the recommended dose and activity of the WEE1 inhibitor adavosertib in combination with carboplatin in children and young adults with molecularly enriched recurrent/refractory malignancies.

PATIENTS AND METHODS

Adavosertib was administered orally, twice every day on Days 1 to 3 and carboplatin intravenously on Day 1 of a 21-day cycle, starting at 100 mg/m2/dose and AUC 5, respectively. Patients were enriched for molecular alterations in cell cycle and/or homologous recombination (HR).

RESULTS

Twenty patients (median age: 14.0 years; range: 3.4-23.5) were included; 18 received 69 treatment cycles. Dose-limiting toxicities were prolonged grade 4 neutropenia and grade 3/4 thrombocytopenia requiring transfusions, leading to two de-escalations to adavosertib 75 mg/m2/dose and carboplatin AUC 4; no recommended phase II dose was defined. Main treatment-related toxicities were hematologic and gastrointestinal. Adavosertib exposure in children was equivalent to that in adults; both doses achieved the cell kill target. Overall response rate was 11% (95% confidence interval, 0.0-25.6) with partial responses in 2 patients with neuroblastoma. One patient with medulloblastoma experienced unconfirmed partial response and 5 patients had stable disease beyond four cycles. Seven of these eight patients with clinical benefit had alterations in HR, replication stress, and/or RAS pathway genes with or without TP53 alterations, whereas TP53 pathway alterations alone (8/10) or no relevant alterations (2/10) were present in the 10 patients without benefit.

CONCLUSIONS

Adavosertib-carboplatin combination exhibited significant hematologic toxicity. Activity signals and identified potential biomarkers suggest further studies with less hematotoxic DNA-damaging therapy in molecularly enriched pediatric cancers.

Myeloprotection with trilaciclib in Chinese patients with extensive-stage small cell lung cancer receiving chemotherapy: Results from a randomized, double-blind, placebo-controlled phase III study (TRACES)

INTRODUCTION

Trilaciclib is a transient cyclin-dependent kinase 4/6 inhibitor that decreases the incidence of chemotherapy-induced myelosuppression in extensive-stage small cell lung cancer (ES-SCLC). TRACES study was designed to assess the safety, efficacy and pharmacokinetics (PK) of trilaciclib before chemotherapy in Chinese patients with ES-SCLC.

METHODS

The study included an open-label safety run-in part (Part 1) and double-blinded, placebo-controlled part (Part 2) where patients received trilaciclib or placebo before chemotherapy. Treatment-naïve or previously treated ES-SCLC patients received intravenous trilaciclib (240 mg/m2) or placebo before etoposide/carboplatin or topotecan, respectively. Primary endpoints were PK, safety and duration of severe neutropenia (DSN) in Cycle 1 in Part 1 and Part 2. Exploratory endpoints included the effect of trilaciclib on other myeloprotection endpoints, safety and antitumor efficacy.

RESULTS

Overall, 95 Chinese patients were enrolled, of which 12 and 83 patients were in Part 1 and Part 2, respectively. In Part 1, trilaciclib was well tolerated. Non-compartmental analysis results revealed no substantial differences in the main exposure parameters. In Part 2, 41 patients received trilaciclib, and 42 received placebo. Patients in trilaciclib arm vs placebo arm had a clinically and statistically significant decrease in DSN (mean [SD]) in Cycle 1 (0 [1.7] vs 2 [3.0] days; P = 0.0003), with improvements in additional neutrophil, red blood cell, and platelet measures. After a median follow-up of 14.1 months, the median overall survival was 12.0 months in trilaciclib arm and 8.8 months in placebo arm (HR, 0.69; 95 % CI: 0.40-1.22). Median progression-free survival was 4.8 months and 4.3 months, respectively (HR, 0.86; 95 % CI: 0.53-1.39). Trilaciclib had a well-tolerated safety profile.

CONCLUSIONS

Trilaciclib in the Chinese population demonstrated a similar PK and safety profile as seen in other global trials. There was significant reduction of DSN in Cycle 1, thereby substantiating the myeloprotective effects of trilaciclib in Chinese ES-SCLC patients.

A Comprehensive Review on the Role of Lurbinectedin in Soft Tissue Sarcomas

OPINION STATEMENT

Soft tissue sarcoma (STS), a substantial group of aggressive and rare tumors with tissue heterogeneity, is infrequently represented in clinical trials with an urgent necessity for newer treatment options. Lurbinectedin, an analog of trabectedin, is currently approved, in various countries, as a single agent, for the treatment of patients with relapsed small cell lung cancer (SCLC). However, preclinical and phase I and phase II trials have demonstrated the efficacy of lurbinectedin in different tumor types, including STS. The better understanding of the pathophysiology and evolution of STS as well as the mechanism of action of lurbinectedin in addition to the available data regarding the activity of this drug in this subset of patients will pave the way to newer therapeutic options and strategies.

Treating patients with platinum-sensitive extensive-stage small-cell lung cancer in a real-world setting

Extensive-stage small-cell lung cancer (ES-SCLC) is an aggressive disease with poor 5-year survival. The first-line standard-of-care for ES-SCLC is platinum plus etoposide, along with 1 of the immune checkpoint inhibitors atezolizumab or durvalumab. Although SCLC first-line therapy often leads to rapid responses, treatment becomes more challenging at progression, particularly for those with a chemotherapy-free interval (CTFI) of ≤6 months. The NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines®) for SCLC no longer specify treatment recommendations in this setting, but options approved by the US Food and Drug Administration include topotecan and lurbinectedin. Participation in a clinical trial is recommended as an option regardless of CTFI. Other NCCN-recommended regimens are paclitaxel, irinotecan, temozolomide, and cyclophosphamide/doxorubicin/vincristine, among others. Nivolumab and pembrolizumab are options in those not previously treated with a checkpoint inhibitor. For patients with platinum-sensitive SCLC (CTFI >6 months), preferred treatment per the NCCN Guidelines® for SCLC is retreatment with platinum and etoposide, although the use of immune checkpoint inhibitors is discouraged if there is progression on a drug in this class. Further research on immunotherapies and combination regimens is ongoing, and continuing work on the subcharacterization of SCLC may lead to better precision of therapies that promote more durable responses in individual patients with ES-SCLC.

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.

The Evolving Pathways of the Efficacy of and Resistance to CDK4/6 Inhibitors in Breast Cancer

The approval of cyclin-dependent kinase 4 and 6 inhibitors (CDK4/6i) in combination with endocrine therapy (ET) has remarkably improved the survival outcomes of patients with advanced hormone receptor-positive (HR+) breast cancer (BC), becoming the new standard of care treatment in these patients. Despite the efficacy of this therapeutic combination, intrinsic and acquired resistance inevitably occurs and represents a major clinical challenge. Several mechanisms associated with resistance to CDK4/6i have been identified, including both cell cycle-related and cell cycle-nonspecific mechanisms. This review discusses new insights underlying the mechanisms of action of CDK4/6i, which are more far-reaching than initially thought, and the currently available evidence of the mechanisms of resistance to CDK4/6i in BC. Finally, it highlights possible treatment strategies to improve CDK4/6i efficacy, summarizing the most relevant clinical data on novel combination therapies involving CDK4/6i.

Real-World Outcomes of Trilaciclib Among Patients with Extensive-Stage Small Cell Lung Cancer Receiving Chemotherapy

INTRODUCTION

Trilaciclib was recently approved in the USA for reducing chemotherapy-induced myelosuppression (CIM) among adults with extensive-stage small cell lung cancer (ES-SCLC) when administered prior to chemotherapy. There is limited understanding of real-world outcomes of trilaciclib.

METHODS

A comprehensive literature review was conducted using a keyword search in the MEDLINE, Embase, and conference abstracts. Additional studies were identified through communications with the authors of relevant studies. Published and unpublished real-world studies of trilaciclib- and comparable non-trilaciclib-treated patients with ES-SCLC were included. Evidence on myelosuppressive hematologic adverse events (HAEs), cytopenia-related healthcare utilization, and other reported outcomes (e.g., hospitalizations, dose reduction, and treatment delay) were synthesized. If feasible, outcomes were compared qualitatively between the trilaciclib and historical reference groups, and between first-line trilaciclib initiators and the overall trilaciclib population. Weighted averages were estimated for selected outcomes using sample size as the weight.

RESULTS

The literature search identified five unique studies based on eight records-two included trilaciclib only, two non-trilaciclib only, and one both. In trilaciclib cohorts, the weighted average prevalence of grade ≥ 3 myelosuppressive HAEs in ≥ 1 lineage, ≥ 2 lineages, and all three lineages was 40.5%, 14.5%, and 7.5%, respectively. All rates were numerically lower compared to the historical non-trilaciclib cohorts (58.8%, 28.0%, 13.0% respectively). Cytopenia-related healthcare utilization was also lower in the trilaciclib cohorts. In general, first-line trilaciclib initiators had numerically lower myelosuppressive HAEs and cytopenia-related healthcare utilization than the overall trilaciclib patients.

CONCLUSIONS

The existing evidence suggests that trilaciclib may reduce single and multilineage grade ≥ 3 myelosuppressive HAEs and cytopenia-related healthcare utilization among patients with ES-SCLC in the real world. It is a promising new treatment for CIM prevention in ES-SCLC and may bring greater benefits to first-line trilaciclib initiators. Future studies are recommended to further evaluate the real-world effectiveness of trilaciclib.

SEOM-GECP Clinical guidelines for diagnosis, treatment and follow-up of small-cell lung cancer (SCLC) (2022)

Small-cell lung cancer (SCLC) is a highly aggressive malignancy comprising approximately 15% of lung cancers. Only one-third of patients are diagnosed at limited-stage (LS). Surgical resection can be curative in early stages, followed by platinum-etoposide adjuvant therapy, although only a minority of patients with SCLC qualify for surgery. Concurrent chemo-radiotherapy is the standard of care for LS-SCLC that is not surgically resectable, followed by prophylactic cranial irradiation (PCI) for patients without progression. For extensive-stage (ES)-SCLC, a combination of platinum and etoposide has historically been a mainstay of treatment. Recently, the efficacy of programmed death-ligand 1 inhibitors combined with chemotherapy has become the new front-line standard of care for ES-SCLC. Emerging knowledge regarding SCLC biology, including genomic characterization and molecular subtyping, and new treatment approaches will potentially lead to advances in SCLC patient care.

Advancements in small cell lung cancer

Small cell lung cancer (SCLC) is a recalcitrant cancer with an urgent need for novel therapeutics, preclinical models, and elucidation of the molecular pathways responsible for its rapid resistance. Recently, there have been many significant advancements in our knowledge of SCLC that led to the development of novel treatments. This review will go over the recent attempts to provide new molecular subcategorization of SCLC, recent breakthroughs in various systemic treatments including immunotherapy, targeted therapy, cellular therapy, as well as advancements in radiation therapy.

The impact of new and emerging agents on outcomes for febrile neutropenia: addressing clinical gaps

PURPOSE OF REVIEW

While chemotherapy treatment options for patients with solid and hematologic malignancies have dramatically improved over recent years, chemotherapy-induced neutropenia (CIN) and febrile neutropenia (FN) remain major barriers to delivering treatment at full doses and optimal timing. Despite concurrent advances in granulocyte colony-stimulating factor (G-CSF) administration, multiple barriers to the administration of and disparities in the access to these agents remain. The introduction of new, emerging agents, including biosimilars and novel therapies show promise in improving outcomes for CIN.

RECENT FINDINGS

The introduction of biosimilar filgrastim products has improved access to G-CSF administration by driving marketplace competition and has reduced costs for both patients and healthcare systems without sacrificing efficacy. Emerging therapies to address similar issues include long-acting G-CSF products, efbemalenograstim alfa and eflapegrastin-xnst, as well as agents with novel mechanisms of action, plinabulin and trilaciclib. These agents have shown efficacy and cost-saving benefits in certain populations and disease groups.

SUMMARY

Multiple emerging agents show promise in decreasing the burden of CIN. Use of these therapies will reduce access disparities and will improve outcomes for patients with cancer receiving cytotoxic chemotherapy. Many ongoing trials are underway to evaluate the roles of these agents for more widespread use.

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.

A Proactive Approach to Prevent Hematopoietic Exhaustion During Cancer Chemotherapy in Older Patients: Temporary Cell-Cycle Arrest

Age is associated with the decline of multiple organ systems. In older patients, hematological toxicities associated with chemotherapy are often dose limiting, impairing dose intensity and treatment efficacy. Contrary to the classical path using growth factors to activate tissue regeneration, a novel strategy is emerging to prevent chemotherapy toxicity that involves temporary cell-cycle arrest of normal cells, such as hematopoietic or epithelial precursors. This proactive approach may allow the sparing of the stem cell reserve of these tissues. Two molecules are included in this new category, trilaciclib and ALRN-6924, which induce cell-cycle arrest by two different pathways. Previous approaches, such as the use of myelopoietic growth factors, were reactive and they might even have accelerated the depletion of stem cells by enhancing the commitment of these elements. Trilaciclib causes cell-cycle arrest by CDK 4/6 inhibition and ALRN-6924 by p53 activation. In a pooled analysis of three randomized phase II studies of patients with small cell lung cancer, trilaciclib prevented neutropenia, thrombocytopenia, and anemia. Similar chemoprotective results were observed with ALRN-6924 in an open-label phase Ib study of patients with p53-mutated small cell lung cancer. Trilaciclib is now approved as a myelopreservation agent in patients with extensive-stage small cell lung cancer. ALRN-6924 is currently in phase Ib clinical development in patients with p53-mutated cancer. In addition to preserving the normal hemopoietic pool, these drugs promise to preserve the stem cell reserve of other normal tissues with high turnover, preventing potentially other dose-limiting toxicities, such as mucositis and diarrhea. An "ex vivo" study provided early evidence that ALRN-6924 may prevent chemotherapy-induced alopecia. By affording protection from multiple toxicities with a single drug, trilaciclib and ALRN-6924 have the potential to transform the current standards of supportive care for oncology patients and may prevent the depletion of tissue stem cells already compromised with age.

Population pharmacokinetics and exposure-response of trilaciclib in extensive-stage small cell lung cancer and triple-negative breast cancer

AIMS

Trilaciclib is a first-in-class, intravenous cyclin-dependent kinase 4/6 inhibitor that provides multilineage protection from chemotherapy-induced myelosuppression. This analysis aimed to characterize the population pharmacokinetics (PK) of trilaciclib, identify potential covariates influencing trilaciclib PK, and evaluate exposure-response relationships in extensive-stage small cell lung cancer (ES-SCLC) and triple-negative breast cancer (TNBC) trials.

METHODS

Population PK analysis was performed using data from healthy volunteers (n = 72), patients with ES-SCLC (n = 111) and patients with TNBC (n = 14). Exposure-response analyses were conducted to investigate the impact of trilaciclib exposure (AUC) on myeloprotective efficacy, antitumour efficacy and safety. Logistic regression and Cox regression models were used for binary and time-to-event endpoints, respectively.

RESULTS

Trilaciclib PK was described by a three-compartment model. Sex, body surface area, baseline albumin concentration and age were identified as significant covariates on trilaciclib PK but did not have clinically relevant impact on exposure. Based on exposure-response analyses, lower and higher exposures of trilaciclib at clinical doses (200-280 mg/m² ) were associated with similar myeloprotective effects. Trilaciclib exposure did not impact the antitumour effects of chemotherapy. Higher exposure to trilaciclib was associated with higher probabilities of headache, phlebitis/thrombophlebitis and injection site reactions.

CONCLUSION

No dose adjustments are required based on the covariates tested. Trilaciclib resulted in optimal myeloprotective effects with no impact on antitumour effects of chemotherapy. However, higher exposure increased the probabilities of adverse events. The data further support selection of the recommended phase 2 dose (trilaciclib 240 mg/m² ).

Chemotherapy-induced thrombocytopenia: literature review

Chemotherapy-induced thrombocytopenia (CIT) is a common condition that frequently results in reduced chemotherapy dosages, postponed treatment, bleeding, and unfavorable oncological outcomes. At present, there is no clear suggestions for preventing or treating CIT. Thrombopoietin (TPO) replacement therapy has been invented and used to treat CIT to promote the production of megakaryocytes and stimulate the formation of platelets. However, this treatment is limited to the risk of immunogenicity and cancer progression. Therefore, an unmet need exists for exploring alternatives to TPO to address the clinical issue of CIT. Application of appropriate therapeutic drugs may be due to understanding the potential mechanisms of CIT. Studies have shown that chemotherapy significantly affects various cells in bone marrow (BM) microenvironment, reduces their ability to support normal hematopoiesis, and may lead to BM damage, including CIT in cancer patients. This review focuses on the epidemiology and treatment of cancer patients with CIT. We also introduce some recent progress to understand the cellular and molecular mechanisms of chemotherapy inhibiting normal hematopoiesis and causing thrombocytopenia.

LP2, a stable lanthipeptide derived from cAng-(1-7), exerts myeloprotective action in mice

OBJECTIVES

Linear unstable angiotensins stimulate hematopoiesis. Here we address: (1) Is cyclic angiotensin-(1-7) myeloprotective in mice? (2) Is cyclic angiotensin-(1-7) stable in rat? (3) Does LP2, a cyclic angiotensin-(1-7) with an N-terminal d-lysine, exert myeloprotective action in tumor-bearing mice?

MATERIALS AND METHODS

Cyclic angiotensin-(1-7)'s capacity to restore levels of blood platelets and white blood cells was studied in gemcitabine-treated mice. The stability of cyclic angiotensin-(1-7) in rat was measured in blood samples taken after injection or infusion. The capacity of LP2 to restore total bone marrow cell levels in mice after treatment with 5-fluoruracil was measured. In addition, the capacity of LP2 to counter anemia in tumor-bearing mice treated with erlotinib was measured.

RESULTS

Cyclic angiotensin-(1-7) dose-dependently restored blood platelet levels in gemcitabine-treated mice, whereas its capacity to restore levels of white blood cells was less. In vivo aminoterminal breakdown of cyclic angiotensin-(1-7) yielded cyclic angiotensin-(2-7) and cyclic angiotensin-(3-7). LP2 significantly (p < .0001 at 100 μg/kg/day) restored bone marrow cell counts in mice after treatment with 5-fluoruracil. LP2 also significantly (p < .05) countered anemia in tumor-bearing mice treated with erlotinib.

CONCLUSIONS

LP2 exerts myeloprotective action with perspectives for continuation of its clinical development.

New Advances in Supportive Care: Chemoprotective Agents as Novel Opportunities in Geriatric Oncology

PURPOSE OF REVIEW

To explore the effectiveness of trilaciclib and ALRN-6924 in the prevention of cancer chemotherapy-induced toxicity in older patients. New chemoprotective agents are necessary because age is the main risk factor for chemotherapy complications that account largely for the poorer outcome of cancer in the elderly. Trilaciclib and ALRN-6924 cause a reversible block of the proliferation of normal cells through cell cycle arrest (CCA). With this mechanism, they may prevent the toxicity of cycle-active cancer treatment including neutropenia, anemia, thrombocytopenia, lymphopenia, mucositis, and alopecia.

RECENT FINDINGS

Myelopoietic growth factors may prevent neutropenia in the aged, but they may cause severe bone pain, may aggravate thrombocytopenia and anemia, and may cause myelodysplasia and acute leukemia as a late complication. The prevention of thrombocytopenia, anemia, mucositis, and alopecia is unsatisfactory at present. These complications may jeopardize the treatment outcome as they require a reduction of treatment dose/intensity and because many patients find the resulting symptoms intolerable. In three studies of patients with extensive disease small cell lung cancer (ES-SCLC), trilaciclib reduced the severity and duration of neutropenia and thrombocytopenia as well as the need for blood transfusions. In addition, it produced a significant expansion of T-cell clones. Trilaciclib received FDA approval for the prevention of chemotherapy-induced myelosuppression in patients with ES-SCLC. ALRN-6924 is currently studied in phase II study of ES-SCLC. In a phase IB of 38 patients, ALRN-6924 prevented myelosuppression to an extent comparable with trilaciclib. Both drugs proved as effective in patients 65 and older as they were in the younger ones. In an "ex vivo" study, ALRN-6924 protected the epithelial stem cells of hair follicles from taxanes and promised to prevent alopecia. The possibility that CCA of tumor cells may reduce the effectiveness of cycle-active chemotherapy is a major concern. For this reason, the use of trilaciclib, an inhibitor of CDK 4/6, should be limited to tumors with inactivated RB1, and the use of ALRN-6924, an inhibitor of P53, should be limited to tumors with inactivated P53. Chemotherapy-related toxicities limit dose intensity and contribute to significant morbidity and mortality in elderly cancer patients. Trilaciclib and ALRN-6924 are of particular interest to geriatric oncologists because of their novel mechanism of action. Ameliorating chemotherapy-induced toxicities holds the promise of transforming the practice of geriatric oncology by enabling chemotherapeutic regimens that are currently not feasible for this patient population. Specifically, these agents may prevent chemotherapy-induced neutropenia and thrombocytopenia, perhaps the most life-threatening complications of cytotoxic chemotherapy, thereby obviating the need for the use of rescue strategies such as hematopoietic growth factors. In addition, these agents offer the potential for broad tissue protection from other chemotherapy-related toxicities, including mucositis, diarrhea, and alopecia, which historically have been poorly managed. Importantly, by preventing a spectrum of chemotherapy-related toxicities, these agents may permit the administration of chemotherapy at full-dose intensity, prevent functional decline, and grant maintenance of resilience to older cancer patients. As a result, the successful prevention of chemotherapy-induced side effects may not only mitigate the costs of care but also improve patient outcomes and quality of life. Finally, chemoprotective strategies offer the opportunity to apply geriatric principles to clinical trials of cancer treatment. In particular, they may allow the testing of prolongation of "active life expectancy" as a major goal of clinical trials in elderly patients. They may also enable novel and more practical forms of clinical trials. By assessing the risk of chemotherapy-related toxicity with the Chemotherapy Risk Assessment Scale for High Age Patients (CRASH) or the Cancer and Aging Research Group (CARG) instruments, these agents may permit researchers to utilize patients as their own controls and endorse the approval of supportive care drugs based upon the risk profile of individual patients.

Trilaciclib prior to gemcitabine plus carboplatin for metastatic triple-negative breast cancer: phase III PRESERVE 2

Triple-negative breast cancer (TNBC) is an aggressive malignancy for which cytotoxic chemotherapy remains the backbone of treatment. Trilaciclib is an intravenous cyclin-dependent kinase 4/6 inhibitor that induces transient cell cycle arrest of hematopoietic stem and progenitor cells and immune cells during chemotherapy exposure, protecting them from chemotherapy-induced damage and enhancing immune activity. Administration of trilaciclib prior to gemcitabine plus carboplatin (GCb) significantly improved overall survival (OS) compared with GCb alone in an open-label phase II trial in patients with metastatic TNBC, potentially through protection and direct activation of immune function. The randomized, double-blind, placebo-controlled, phase III PRESERVE 2 trial will evaluate the efficacy and safety of trilaciclib administered prior to GCb in patients with locally advanced unresectable or metastatic TNBC. Clinical Trial Registration: NCT04799249 (ClinicalTrials.gov).

Precision Medicine Highlights Dysregulation of the CDK4/6 Cell Cycle Regulatory Pathway in Pediatric, Adolescents and Young Adult Sarcomas

Simple Summary

This review provides an overview of clinical features and current therapies in children, adolescents, and young adults (AYA) with sarcoma. It highlights the basic and clinical findings on the cyclin-dependent kinases 4 and 6 (CDK4/6) cell cycle regulatory pathway in the context of the precision medicine-based molecular profiles of the three most common types of pediatric and AYA sarcomas—osteosarcoma (OS), rhabdomyosarcoma (RMS), and Ewing sarcoma (EWS).

Abstract

Despite improved therapeutic and clinical outcomes for patients with localized diseases, outcomes for pediatric and AYA sarcoma patients with high-grade or aggressive disease are still relatively poor. With advancements in next generation sequencing (NGS), precision medicine now provides a strategy to improve outcomes in patients with aggressive disease by identifying biomarkers of therapeutic sensitivity or resistance. The integration of NGS into clinical decision making not only increases the accuracy of diagnosis and prognosis, but also has the potential to identify effective and less toxic therapies for pediatric and AYA sarcomas. Genome and transcriptome profiling have detected dysregulation of the CDK4/6 cell cycle regulatory pathway in subpopulations of pediatric and AYA OS, RMS, and EWS. In these patients, the inhibition of CDK4/6 represents a promising precision medicine-guided therapy. There is a critical need, however, to identify novel and promising combination therapies to fight the development of resistance to CDK4/6 inhibition. In this review, we offer rationale and perspective on the promise and challenges of this therapeutic approach.

Pharmacokinetic Drug-Drug Interaction Studies Between Trilaciclib and Midazolam, Metformin, Rifampin, Itraconazole, and Topotecan in Healthy Volunteers and Patients with Extensive-Stage Small-Cell Lung Cancer

Background and Objective

Trilaciclib is a cyclin-dependent kinase 4/6 inhibitor indicated to decrease the incidence of chemotherapy-induced myelosuppression in patients with extensive-stage small-cell lung cancer. Trilaciclib is a substrate and time-dependent inhibitor of cytochrome P450 3A4 and an inhibitor of multidrug and toxin extrusion 1, multidrug and toxin extrusion 2-K, organic cation transporter 1, and organic cation transporter 2. Here, we investigate the pharmacokinetic drug–drug interaction potential of trilaciclib.

Methods

Two phase I studies were conducted as prospective, open-label, fixed-sequence drug–drug interaction studies in healthy subjects (n = 57, n = 20) to investigate potential interactions between intravenously administered trilaciclib (200 or 240 mg/m²) and orally administered midazolam (5 mg), metformin (1000 mg), itraconazole (200 mg), and rifampin (600 mg). A population pharmacokinetic model was fit to phase Ib/IIa data in patients with extensive-stage small-cell lung cancer (n = 114) to assess the impact of trilaciclib dose and exposure (area under the plasma concentration–time curve) on topotecan clearance.

Results

Coadministration with trilaciclib had minimal effects on the exposure (area under the plasma concentration–time curve from time 0 to infinity) of midazolam (geometric least-square mean ratio [GMR] vs midazolam alone 1.065; 90% confidence interval [CI] 0.984–1.154) but statistically significantly increased plasma exposure (GMR 1.654; 90% CI 1.472–1.858) and decreased renal clearance (GMR 0.633; 90% CI 0.572–0.701) of metformin. Coadministration of trilaciclib with rifampin or itraconazole decreased trilaciclib area under the plasma concentration–time curve from time 0 to infinity by 17.3% (GMR 0.827; 90% CI 0.785–0.871) and 14.0% (GMR 0.860; 0.820–0.902), respectively, vs trilaciclib alone. Population pharmacokinetic modeling showed no significant effect of trilaciclib on topotecan clearance.

Conclusions

Overall, the drug–drug interaction and safety profiles of trilaciclib in these studies support its continued use in patients with extensive-stage small-cell lung cancer.

Clinical Trial Registration

Study 106: EudraCT number: 2019-002303-18; Study 114: not applicable; Study 03: Clinicaltrials.org: NCT02514447; August 2015.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40261-022-01179-x.

Treatment patterns and burden of myelosuppression for patients with small cell lung cancer: A SEER-medicare study

PURPOSE

To depict the treatment journey for patients with small cell lung cancer (SCLC) and evaluate health care resource utilization (HCRU) associated with myelosuppression, a complication induced by chemotherapy or chemotherapy plus radiation therapy.

PATIENTS AND METHODS

This was a descriptive, retrospective study of patients with SCLC aged ≥65 years, identified from linked Surveillance, Epidemiology, and End Results (SEER)-Medicare data curated between January 2012 and December 2015. Treatment types (chemotherapy, radiation therapy, surgery) were classified as first, second, or third line, depending on the temporal sequence in which regimens were prescribed. For each year, the proportions of patients completing 4- or 6-cycle chemotherapy regimens, with hospital admissions associated with myelosuppression, or who used granulocyte colony-stimulating factors (G-CSFs), blood/platelet transfusions, or erythropoiesis-stimulating agents (ESAs), were calculated.

RESULTS

Chemotherapy was administered as initial treatment in 7,807/11,907 (65.6%) patients whose treatment journey was recorded. Approximately one-third (n = 3,985) subsequently received radiation therapy. In total, 5,791 (57.8%) patients completed the guideline-recommended 4-6 cycles of chemotherapy. Among all chemotherapy-treated patients, 10,370 (74.3%) experienced ≥1 inpatient admission associated with myelosuppression (anemia, 7,366 [52.8%]; neutropenia, 4,642 [33.3%]; thrombocytopenia, 2,375 [17.0%]; pancytopenia, 1,983 [14.2%]). Supportive care interventions included G-CSF (6,756 [48.4%] patients), ESAs (1,534 [11.0%]), and transfusions (3,674 [26.3%]).

CONCLUSION

Chemotherapy remains a cornerstone of care for patients with SCLC. Slightly over half of patients completed the recommended number of cycles, underscoring the frailty of patients and aggressiveness of SCLC. HCRU associated with myelosuppression was prominent, suggesting a substantial burden on older patients with SCLC.

Cyclin-dependent Kinases 4/6 Inhibitors in Neuroendocrine Neoplasms: from Bench to Bedside

PURPOSE OF REVIEW

Cyclin-dependent kinases (CDKs) are key regulators that play an important role in cell division. Palbociclib, ribociclib and abemaciclib showed significant antitumor activity in several malignancies and, recently, also a myeloprotective effect for trilaciclib when added to chemotherapy. The purpose of this review is to highlight the current evidence for CDK4/6 inhibitors in neuroendocrine neoplasms (NENs).

RECENT FINDINGS

Preclinical results showed a promising antitumor activity of CDK4/6 inhibitors in neuroendocrine tumors (NETs), but so far, the very few small clinical trials did not show a strong impact on progression free survival (PFS) and objective response in NETs. Meanwhile, the CDK4/6 inhibitor trilaciclib revealed significant effects in reducing chemotherapy-induced myelosuppression in small cell lung cancer (SCLC). Up to date, CDK4/6 inhibitors are still considered investigational in NETs as antitumor agents, whereas trilaciclib can be used in the routine clinical practice in extensive stage SCLC patients for reducing myelotoxicity of standard chemotherapy.

Budget impact analysis of trilaciclib for decreasing the incidence of chemotherapy-induced myelosuppression in patients with extensive-stage small cell lung cancer in the United States

BACKGROUND: Chemotherapy-induced myelosuppression, which commonly manifests as neutropenia, anemia, and/or thrombocytopenia, is a frequent and severe complication of standard treatment regimens for patients with extensive-stage small cell lung cancer (ES-SCLC). Trilaciclib is a first-in-class myeloprotective therapy indicated to decrease the incidence of chemotherapy-induced myelosuppression when administered prior to a platinum-/etoposide-containing regimen or topotecan-containing regimen for ES-SCLC. OBJECTIVE: To estimate the budget impact of administering trilaciclib prior to chemotherapy to manage chemotherapy-induced myelosuppression in adults with ES-SCLC from a US payer perspective. METHODS: A budget impact model was developed to assess the impact of introducing trilaciclib to a hypothetical 1 million-member health insurance plan. The model compared 2 market scenarios: a current scenario of standard treatments for ES-SCLC without trilaciclib, and an alternative scenario of standard treatment plus trilaciclib. Population, clinical, and cost inputs were derived from published literature and trilaciclib clinical trial data. Model outcomes included the number of myelosuppressive adverse events (AEs), costs of treatment, costs of AE management, total cost, and per-member per-month (PMPM) costs. The budget impact of trilaciclib was calculated as the difference in cost (2021 US dollars) between the 2 scenarios over a 1- to 5-year time horizon. Scenario and deterministic sensitivity analyses were conducted to assess uncertainty around key model inputs. RESULTS: An estimated total of 301 patients were eligible for treatment with trilaciclib over a 5-year period. The use of trilaciclib was estimated to reduce the number of myelosuppressive AEs over a 5-year period (events avoided included 108 for neutropenia, 7 for febrile neutropenia, 23 for anemia, and 46 for thrombocytopenia) compared with the scenario without trilaciclib. The adoption of trilaciclib was associated with a cost saving of $801,254 ($0.013 PMPM) over 5 years. The acquisition cost for trilaciclib ($3,704,199) was offset by the reduction in AE management cost ($4,282,748) and reduction in prophylactic granulocyte colony-stimulating factor use ($222,704). The cost savings associated with trilaciclib began in year 1 (total $34,388; $0.003 PMPM) and accrued over time. CONCLUSIONS: The acquisition cost of trilaciclib is projected to be offset by a reduction in the costs of managing AEs related to myelosuppression when added to standard chemotherapy regimens for ES-SCLC. The net budget impact of trilaciclib is estimated to be a cost saving. DISCLOSURES: This research was funded by G1 Therapeutics, Inc., and implemented by ZS Associates, an independent consultancy that collated the model inputs and performed the budget impact analysis. The study sponsor was involved in the study design; collection, analysis, and interpretation of data; writing of the report; and the decision to submit the report for publication. The journal open access fee was funded by G1 Therapeutics, Inc. Moran, Chioda, and Huang are employed by G1 Therapeutics, Inc. Chioda and Huang report stocks and stock options for G1 Therapeutics, Inc. Goyal and Deniz are employed by ZS Associates. Goyal reports consulting fees from G1 Therapeutics, Inc. Abraham reports consulting fees from Coherus, G1 Therapeutics, Inc. (unrelated to this study and manuscript), Mylan/Viatris, and Sandoz and participation on a data safety monitoring board or advisory board for G1 Therapeutics, Inc. MacDonald reports consulting fees from Coherus, G1 Therapeutics, Inc. (unrelated to this study and manuscript), Mylan/Viatris, and Sandoz. Deniz reports no disclosures. A synopsis of the current study was presented in poster format at the Virtual AMCP Annual Meeting, April 12-16, 2021.

Small Cell Lung Cancer, Version 2.2022, NCCN Clinical Practice Guidelines in Oncology

The NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines) for Small Cell Lung Cancer (SCLC) provide recommended management for patients with SCLC, including diagnosis, primary treatment, surveillance for relapse, and subsequent treatment. This selection for the journal focuses on metastatic (known as extensive-stage) SCLC, which is more common than limited-stage SCLC. Systemic therapy alone can palliate symptoms and prolong survival in most patients with extensive-stage disease. Smoking cessation counseling and intervention should be strongly promoted in patients with SCLC and other high-grade neuroendocrine carcinomas. The "Summary of the Guidelines Updates" section in the SCLC algorithm outlines the most recent revisions for the 2022 update, which are described in greater detail in this revised Discussion text.

Trilaciclib and the economic value of multilineage myeloprotection from chemotherapy-induced myelosuppression among patients with extensive-stage small cell lung cancer treated with first-line chemotherapy

AIMS

Proliferating hematopoietic stem and progenitor cells (HSPCs) are susceptible to chemotherapy-induced damage, resulting in myelosuppressive adverse events (AEs) such as neutropenia, anemia, and thrombocytopenia that are associated with high health care costs and decreased quality of life (QoL). In this study, a trial-based cost-effectiveness analysis was performed to help assess the economic impact of administering trilaciclib, a myeloprotective therapy that protects multilineage HSPCs from chemotherapy-induced damage, prior to standard first-line chemotherapy, using data from a pivotal Phase II study of trilaciclib in the setting of extensive-stage small cell lung cancer (ES-SCLC, NCT03041311).

METHOD

The aim of this study was to assess the cost-effectiveness of administering trilaciclib prior to chemotherapy versus chemotherapy alone among patients with ES-SCLC from a United States payer perspective. Data on the rate and frequency of myelosuppressive AEs and health utility were derived from the pivotal study of trilaciclib. Costs of managing myelosuppressive AEs and costs of chemotherapy treatment were sourced from published literature. Outcomes included the number of myelosuppressive AEs, costs (in 2021 US dollars), quality-adjusted life-years (QALYs), incremental cost, incremental QALY, and an incremental cost-effectiveness ratio.

RESULTS

Administering trilaciclib prior to chemotherapy was associated with a reduction in neutropenia (82%), febrile neutropenia (75%), anemia (43%), and thrombocytopenia (96%) compared with chemotherapy alone. Additionally, trilaciclib prior to chemotherapy was cost-saving compared with chemotherapy alone ($99,919 vs $118,759, respectively) and associated with QALY improvement (0.150 vs 0.145, respectively). Probabilistic sensitivity analyses showed 58% of iterations projecting cost savings and QALY improvement with trilaciclib.

CONCLUSIONS

The findings suggest that the use of trilaciclib prior to first-line chemotherapy in patients with ES-SCLC can be cost-beneficial owing to fewer myelosuppressive AEs and lower costs, together with a favorable QoL profile.

Advances in Treatment of Recurrent Small Cell Lung Cancer (SCLC): Insights for Optimizing Patient Outcomes from an Expert Roundtable Discussion

Second-line treatment options for patients with relapsed, extensive-stage small cell lung cancer (ES-SCLC) are limited, and even with currently available treatments, prognosis remains poor. Until recently, topotecan (a topoisomerase I inhibitor) was the only drug approved by the United States (US) Food and Drug Administration (FDA) for the management of ES-SCLC following progression after first-line treatment with etoposide plus a platinum derivative (EP; carboplatin preferred). With the most recent approval of EP plus a programmed death ligand 1 (PD-L1) inhibitor, there are now more therapeutic options for managing ES-SCLC. A number of novel agents have emerging data for activity in relapsed ES-SCLC, and single-agent lurbinectedin (an alkylating drug and selective inhibitor of oncogenic transcription and DNA repair machinery in tumor cells) has conditional FDA approval for use in this patient population. Trilaciclib, a short-acting cyclin-dependent kinase 4/6 (CDK 4/6) inhibitor, has also been recently approved as a supportive intervention for use prior to an EP or a topotecan-containing regimen to diminish the incidence of chemotherapy-induced myelosuppression. The current review is based on a recent expert roundtable discussion and summarizes current therapeutic agents and emerging data on newer agents and biomarkers. It also provides evidence-based clinical considerations and a treatment decision tool for oncologists treating patients with relapsed ES-SCLC. This paper discusses the importance of various factors to consider when selecting a second-line treatment option, including prior first-line treatment, available second-line treatment options, tumor platinum sensitivity, and patient characteristics (such as performance status, comorbidities, and patient-expressed and perceived values).

Myeloprotective Effects of Trilaciclib Among Patients with Small Cell Lung Cancer at Increased Risk of Chemotherapy-Induced Myelosuppression: Pooled Results from Three Phase 2, Randomized, Double-Blind, Placebo-Controlled Studies

Purpose

Trilaciclib is an intravenous cyclin-dependent kinase 4/6 inhibitor indicated to decrease the incidence of chemotherapy-induced myelosuppression (CIM) by protecting hematopoietic stem and progenitor cells and immune system function from chemotherapy-induced damage (myeloprotection). Here, we investigated the myeloprotective effects of trilaciclib among patients at increased risk of CIM.

Patients and Methods

Data were pooled from three randomized, double-blind, placebo-controlled, phase 2 clinical studies of trilaciclib administered prior to chemotherapy in patients with extensive-stage small cell lung cancer (ES-SCLC). Myeloprotective outcomes were evaluated in patient subgroups based on age (<65 or ≥65 years), risk of chemotherapy-induced febrile neutropenia (FN), and risk of anemia or red blood cell (RBC) transfusions. For the FN and anemia analyses, risk factors were identified from published literature and used to classify patients into FN and anemia risk categories. Subgroup analysis based on age was also performed on patient reported outcome (PRO) measures.

Results

In total, 123 patients received trilaciclib and 119 patients received placebo. Myeloprotective benefits of trilaciclib were observed regardless of age, with greater effects observed among patients aged ≥65 years. Across FN risk factors and categories, trilaciclib had beneficial effects on neutrophil-related endpoints vs placebo, with greater effects observed in patients at higher risk of FN. Effects on RBC-related endpoints favored trilaciclib vs placebo, regardless of anemia risk factors and categories. Improvements in PROs with trilaciclib were observed irrespective of age group, but with greater improvements and less deterioration from baseline observed in older patients.

Conclusion

By both decreasing the incidence of CIM and improving quality of life, trilaciclib has the potential to allow patients receiving chemotherapy for ES-SCLC, including patients who are older or more vulnerable to CIM, to receive chemotherapy on schedule and at standard-of-care doses, and to improve the experience for patients receiving chemotherapy to treat ES-SCLC.

Clinical Trial Numbers

NCT02499770; NCT03041311; NCT02514447.

Trilaciclib prior to chemotherapy reduces the usage of supportive care interventions for chemotherapy-induced myelosuppression in patients with small cell lung cancer: Pooled analysis of three randomized phase 2 trials

Background

Supportive care interventions used to manage chemotherapy‐induced myelosuppression (CIM), including granulocyte colony‐stimulating factors (G‐CSFs), erythropoiesis‐stimulating agents (ESAs), and red blood cell (RBC) transfusions, are burdensome to patients and associated with greater costs to health care systems. We evaluated the utilization of supportive care interventions and their relationship with the myeloprotective agent, trilaciclib.

Methods

Data were pooled from three independent randomized phase 2 clinical trials of trilaciclib or placebo administered prior to chemotherapy in patients with extensive‐stage small cell lung cancer (ES‐SCLC). The impact of supportive care on the duration of severe neutropenia (DSN), occurrence of severe neutropenia (SN), and occurrence of RBC transfusions on/after week 5 was analyzed across cycles 1–4. Concordance and association between grade 3/4 anemia, RBC transfusions on/after week 5, and ESA administration was also evaluated.

Results

The use of G‐CSFs, ESAs, or RBC transfusions on/after week 5 was significantly lower among patients receiving trilaciclib versus placebo (28.5% vs. 56.3%, p < 0.0001; 3.3% vs. 11.8%, p = 0.0254; and 14.6% vs. 26.1%, p = 0.0252, respectively). Compared with placebo, trilaciclib significantly reduced DSN and SN, irrespective of G‐CSF administration. RBC transfusions and ESAs were most often administered in patients with grade 3/4 anemia; however, patients typically received RBC transfusions over ESA administration.

Conclusions

By improving CIM and reducing the need for associated supportive care, trilaciclib has the potential to reduce the burden of myelosuppression on patients receiving myelosuppressive chemotherapy for the treatment of ES‐SCLC.

Trial registration

ClinicalTrials.gov (NCT02499770; NCT03041311; NCT02514447).

Improving Outcomes of Chemotherapy: Established and Novel Options for Myeloprotection in the COVID-19 Era

Chemotherapy-induced damage of hematopoietic stem and progenitor cells (HPSCs) often results in myelosuppression that adversely affects patient health and quality of life. Currently, chemotherapy-induced myelosuppression is managed with chemotherapy dose delays/reductions and lineage-specific supportive care interventions, such as hematopoietic growth factors and blood transfusions. However, the COVID-19 pandemic has created additional challenges for the optimal management of myelosuppression. In this review, we discuss the impact of this side effect on patients treated with myelosuppressive chemotherapy, with a focus on the prevention of myelosuppression in the COVID-19 era. During the COVID-19 pandemic, short-term recommendations on the use of supportive care interventions have been issued with the aim of minimizing the risk of infection, reducing the need for hospitalization, and preserving limited blood supplies. Recently, trilaciclib, an intravenous cyclin-dependent kinase 4 and 6 inhibitor, was approved to decrease the incidence of myelosuppression in adult patients when administered prior to platinum/etoposide-containing or topotecan-containing chemotherapy for extensive-stage small cell lung cancer (ES-SCLC). Approval was based on data from three phase 2 placebo-controlled clinical studies in patients with ES-SCLC, showing that administering trilaciclib prior to chemotherapy significantly reduced multilineage myelosuppression, with patients receiving trilaciclib having fewer chemotherapy dose delays/reductions and myelosuppression/sepsis-related hospitalizations, and less need for supportive care interventions, compared with patients receiving placebo. Several other novel agents are currently in clinical development for the prevention or treatment of multilineage or single-lineage myelosuppression in patients with various tumor types. The availability of treatments that could enable patients to maintain standard-of-care chemotherapy regimens without the need for additional interventions would be valuable to physicians, patients, and health systems.