Standard versus Dose-Intensified Chemotherapy with Sequential Reinfusion of Hematopoietic Progenitor Cells in Small Cell Lung Cancer Patients with Favorable Prognosis

Phase I Clinical Trial of Autologous Hematopoietic Stem Cell Transplantation-Supported Dose-Intensified Chemotherapy With Adebrelimab as First-Line Treatment for Extensive-Stage Small Cell Lung Cancer

BACKGROUND

Small cell lung cancer (SCLC) is initially highly sensitive to chemotherapy, which often leads to significant tumor reduction. However, the majority of patients eventually develop resistance, and the disease is further complicated by its "cold" tumor microenvironment, characterized by low tumor immunogenicity and limited CD8+ T cell infiltration. These factors contribute to the poor response to immunotherapy in many cases of extensive-stage SCLC (ES-SCLC). High-dose chemotherapy has shown potential in enhancing tumor cytoreduction, but its use is often limited by severe hematologic toxicity. Combining chemotherapy with immune checkpoint inhibitors (ICIs) can create a synergistic effect by promoting immunogenic cell death and enhancing immune activation. Autologous hematopoietic stem cell transplantation (auto-HSCT) provides a means to support hematopoietic recovery, mitigate chemotherapy-induced myelosuppression, and contribute to immune reconstitution. In this context, the integration of auto-HSCT with dose-intensified chemotherapy and ICIs aims to both protect the bone marrow and enhance antitumor immune responses, potentially overcoming resistance to immunotherapy in ES-SCLC.

METHODS

A phase I, single-center, single-arm trial was designed to evaluate the safety and efficacy of auto-HSCT-supported dose-intensified chemotherapy combined with adebrelimab in treatment-naive ES-SCLC patients. Participants will receive induction chemotherapy followed by stem cell mobilization, apheresis, and cryopreservation. After successful mobilization, consolidation chemotherapy with stem cell reinfusion and granulocyte colony-stimulating factor (G-CSF) support will be performed. Maintenance therapy with adebrelimab continues until disease progression or unacceptable toxicity. Safety and efficacy data, including adverse events, objective response rate (ORR), progression-free survival (PFS), and overall survival (OS), will be analyzed.

RESULTS

The study aims to enhance treatment outcomes by overcoming resistance to immuno-chemotherapy and promoting immune reconstitution. The trial is ongoing at the First Affiliated Hospital of Guangzhou Medical University.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT06597513.

Clinical Benefits of new Systemic Therapy for Small-Cell Lung Cancer Over Two Decades: A Cross-Sectional Study

INTRODUCTION

Small cell lung cancer (SCLC) is one of the most lethal malignancies worldwide. This study aimed to examine the clinical benefits of new systemic therapies derived from randomized controlled trials (RCTs) published from 2002 to 2023 based on the magnitude of clinical benefit scale developed by the European Society for Medical Oncology (ESMO-MCBS).

METHODS

We searched PubMed for Phase 3 RCTs on systemic therapy for SCLC published between January 2002 and December 2023. Therapeutic benefit was graded from 5 to 1 according to the ESMO-MCBS framework, with a score of 4 or 5 representing a meaningful clinical benefit. The statistical power of the trial design was also assessed using ESMO-MCBS.

RESULTS

Sixty-four RCTs with 23 683 participants were eligible for inclusion. The number of RCTs related to molecular targeted therapy or immunotherapy has increased over the years. Among the 62 RCTs for which statistical power could be evaluated, 38 (61.3%) were designed to identify an effect size that would meet the ESMO-MCBS benefit threshold and were less likely to investigate second- or subsequent-line treatment (15.8% vs. 50.0%, p = 0.004), have noninferiority design (0% vs. 25.0%, p = 0.002) and set PFS (0% vs. 16.7%) or response rate (0% vs. 16.7%) as the only primary endpoint (p = 0.002). The ESMO-MCBS framework was applied in 29 RCTs reporting positive results, and only 8 (27.6%) met the threshold for a clinical benefit. The RCTs designed to detect differences that would meet the thresholds were more likely to demonstrate meaningful clinical benefit (87.5% vs. 50.0%, p = 0.099).

CONCLUSION

Most positive SCLC-RCTs did not meet the ESMO-MCBS threshold for meaningful clinical benefits. Strict power calculations should be adopted in the design of future RCTs.

Benefits of surgery in the multimodality treatment of stage IIB-IIIC small cell lung cancer

Surgery combined with chemotherapy/radiotherapy is recommended for early stage small cell lung cancer (SCLC); however, the role of surgery in the multimodality treatment of advanced disease remains controversial. The clinical data of patients between 2000 and 2015 were obtained from the Surveillance, Epidemiology, and End Results database. The surgery group included 998 patients with stage IIB-IIIC. A matched non-surgery group (n = 2994) was generated by propensity score matching. The Kaplan-Meier method and log-rank tests were used for survival analyses. Univariate and multivariate analyses were used to identify significant prognostic factors. After matching, there were no significant differences between the two groups in race, age, sex, T classification, N classification, TNM stage, marital status, primary sites, and origin record NAACCR Hispanic Identification Algorithm (NHIA). The surgery group showed better overall survival and cancer-specific survival than the non-surgery group. Univariate and multivariate analyses showed that therapy methods, age, sex, T classification, and N classification were independent prognostic predictors for stage IIB-IIIC SCLC (all P < 0.05). Stratified analyses showed that survival outcomes favored surgery in any age groups, men and women, any T classification except T3, and N0-2 but not N3 compared with non-surgical treatment. The survival differences favored surgery in stage IIB and IIIA SCLC, although they were not significant in stage IIB and IIIC SCLC. Therefore, surgery was associated with improved survival in stage IIB and IIIA SCLC, but not in stage IIIB and IIIC SCLC.

Chemotherapy of lung cancer: A global perspective of the role of ifosfamide

The oxazaphosphorine cytostatic ifosfamide (IFO) has been successfully integrated in the treatment of various hematological and solid tumors. The purpose of this review is to summarize the evidence for its use in lung cancer starting from basic data of preclinical studies followed by a global summary of the phase III and seminal phase II clinical studies. Global in double respect: first covering both the small cell as well as the non-small cell indications, and, second tracing those studies performed in Europe and the United States as well as those from Asian countries.

Chemoradiotherapy in limited-disease small-cell lung cancer

SUMMARY Systemic chemotherapy is the mainstay of treatment for small-cell lung cancer. A third of small-cell lung cancer patients present with limited disease; in this population, thoracic radiotherapy caused a 14% reduction in the mortality rate, and benefit in terms of overall survival at 3 years was 5.4% as compared with chemotherapy alone. Although the optimal schedule and volume of thoracic radiotherapy remain controversial, early twice-daily concurrent radiotherapy with etoposide plus cisplatin is recommended. Prophylactic cranial irradiation is recommended for patients with any response to first-line treatment. Maintenance and dose-intense treatment is not recommended outside of clinical trials. Large randomized trials that compare standard-dose radiation therapy of 45 Gy in twice-daily fractions for 3 weeks with once-daily schedules with a higher total dose are ongoing. The incorporation of new drugs is warranted for future combined modality treatment.

Extensive disease small cell lung cancer dose-response relationships: implications for resistance mechanisms

BACKGROUND

Some studies (but not others) suggested that high doses are beneficial in small cell lung cancer (SCLC). We hypothesized that dose-response curve (DRC) shape reflects resistance mechanisms.

METHODS

We reviewed published SCLC clinical trials and converted response rates into estimated mean tumor cell kill, assuming killing is proportional to reduction in tumor volume. Mean % cell survival was plotted versus planned dose intensity. Nonlinear and linear meta-regression analyses (weighted according to the number of patients in each study) were used to assess DRC characteristics.

RESULTS

Although associations between dose and cell survival were not statistically significant, DRCs sloped downward for five of seven agents across all doses and for all seven when lowest doses were excluded. Maximum mean cell kill across all drugs and doses was approximately 90%, suggesting that there may be a maximum achievable tumor cell kill irrespective of number of agents or drug doses.

CONCLUSIONS

Downward DRC slopes suggest that maintaining relatively high doses may possibly maximize palliation, although the associations between dose and slope did not achieve statistical significance, and slopes for most drugs tended to be shallow. DRC flattening at higher doses would preclude cure and would suggest that "saturable passive resistance" (deficiency of factors required for cell killing) limits maximum achievable cell kill. An example of factors that could flatten the DRC at higher doses and lead to saturable passive resistance would be presence of quiescent, noncycling cells.

Retinoblastoma tumor suppressor gene expression determines the response to sequential flavopiridol and doxorubicin treatment in small-cell lung carcinoma

PURPOSE

Small-cell lung cancers (SCLC) are defective in many regulatory mechanisms that control cell cycle progression, i.e., functional retinoblastoma protein (pRb). Flavopiridol inhibits proliferation and induces apoptosis in SCLC cell lines. We hypothesized that the sequence flavopiridol followed by doxorubicin would be synergistic in pRb-deficient SCLC cells.

EXPERIMENTAL DESIGN

A H69 pRb-deficient SCLC cell line, H865, with functional pRb and H865 pRb small interfering RNA (siRNA) knockdown cells were used for in vitro and in vivo experiments. The in vivo efficiencies of various sequential combinations were tested using nude/nude athymic mice and human SCLC xenograft models.

RESULTS

Flavopiridol then doxorubicin sequential treatment was synergistic in the pRB-negative H69 cell line. By knocking down pRb with specific siRNA, H865 clones with complete pRb knockdown became sensitive to flavopiridol and doxorubicin combinations. pRb-deficient SCLC cell lines were highly sensitive to flavopiridol-induced apoptosis. pRb-positive H865 cells arrested in G0-G1 with flavopiridol exposure, whereas doxorubicin and all flavopiridol/doxorubicin combinations caused a G2-M block. In contrast, pRb-negative SCLC cells did not arrest in G0-G1 with flavopiridol exposure. Flavopiridol treatment alone did not have an in vivo antitumor effect, but sequential flavopiridol followed by doxorubicin treatment provided tumor growth control and a survival advantage in Rb-negative xenograft models, compared with the other sequential treatments.

CONCLUSIONS

Flavopiridol and doxorubicin sequential treatment induces potent in vitro and in vivo synergism in pRb-negative SCLC cells and should be clinically tested in tumors lacking functional pRB.

Efficacy of intensified chemotherapy with hematopoietic progenitors in small-cell lung cancer: A meta-analysis of the published literature

OBJECTIVE

It remains controversial whether intensified chemotherapy with hematopoietic progenitors (ICHP) is effective for small-cell lung cancer. This meta-analysis was performed to evaluate the efficacy and safety of ICHP in patients with small-cell lung cancer.

METHODS

MEDLINE and EMBASE databases were searched for English-language studies published through October 12, 2008. Randomized phase II and III clinical trials comparing ICHP with control therapy. Response rates, overall survival, and toxicity were analyzed.

RESULTS

Five assessable trials were identified including 641 patients. No significant increase in the odds ratio for response was attributable to ICHP (odds ratio, 1.29; 95% confidence interval, 0.87-1.93; p=0.206). No statistically significant increase in overall survival was found when ICHP were compared to control regimens (hazard ratio, 0.94; 95% confidence interval, 0.80-1.10; p=0.432). The toxicity of ICHP was significantly higher for hematologic toxicity, including hemoglobin nadir and platelet nadir.

CONCLUSIONS

ICHP was not superior to control chemotherapy in terms of both objective response and overall survival, and was related to more significant hemoglobin nadir and platelet nadir.