Survival benefit with checkpoint inhibitors versus chemotherapy is modified by brain metastases in patients with recurrent small cell lung cancer

Introduction

Small cell lung cancer (SCLC) is a rapidly growing malignancy with early distant metastases. Up to 70% will develop brain metastases, and the poor prognosis of these patients has not changed considerably. The potential of checkpoint inhibitors (CPI) in treating recurrent (r/r) SCLC and their effect on brain metastases remain unclear.

Methods

In this retrospective multicenter study, we analyzed r/r SCLC patients receiving second or further-line CPI versus chemotherapy between 2010 and 2020. We applied multivariable-adjusted Cox regression analysis to test for differences in 1-year mortality and real-world progression. We then used interaction analysis to evaluate whether brain metastases (BM) and/or cranial radiotherapy (CRT) modified the effect of CPI versus chemotherapy on overall survival.

Results

Among 285 patients, 99 (35%) received CPI and 186 (65%) patients received chemotherapy. Most patients (93%) in the CPI group received nivolumab/ipilimumab. Chemotherapy patients were entirely CPI-naïve and only one CPI patient had received atezolizumab for first-line treatment. CPI was associated with a lower risk of 1-year mortality (adjusted Hazard Ratio [HRadj] 0.59, 95% CI 0.42 to 0.82, p=0.002). This benefit was modified by BM and CRT, indicating a pronounced effect in patients without BM (with CRT: HRadj 0.34, p=0.003; no CRT: HRadj 0.50, p=0.05), while there was no effect in patients with BM who received CRT (HRadj 0.85, p=0.59).

Conclusion

CPI was associated with a lower risk of 1-year mortality compared to chemotherapy. However, the effect on OS was significantly modified by intracranial disease and radiotherapy, suggesting the benefit was driven by patients without BM.

Additional chemotherapy for EGFRm patients with the continued presence of plasma ctDNA EGFRm at week 3 after start of osimertinib first-line treatment (PACE)

TPS9157

Background: Epidermal growth factor receptor (EGFR) – mutated non-small cell lung cancer (NSCLC) is susceptible to EGFR targeting tyrosine kinase inhibitors (TKI), such as the third generation TKI osimertinib. However, response rate and duration vary between patients. Among others, the specific subtype of EGFR-mutation, its co-occurrence with other genetic alterations, and the detection of phosphorylated EGFR (pEGFR) in the plasma, and its clearance upon treatment were previously identified as markers that predict therapy response. A high proportion of patients with early (3-6 weeks after start) pEGFR clearance from plasma show impressive survival upon single-agent TKI. However, failure to achieve early clearance upon Osimertinib is associated with unfavorable outcome. For these patients, treatment concepts are lacking. Here, we report about the initiation of a clinical trial that evaluates the combination of EGFR-directed TKI and platinum-based chemotherapy as an early treatment escalation strategy for this high-risk patient population. Methods: PACE is a prospective multicenter single-arm investigator-initiated phase II trial. Patients with NSCLC harboring L858R or del19 EGFR mutation, who are treated with first-line Osimertinib are subjected to liquid biopsy-based early response assessment three weeks after start of therapy. Failure to clear pEGFR from plasma at this time point triggers treatment escalation with the addition of platinum-based doublet chemotherapy to the Osimertinib treatment. The primary outcome measure of the trial is progression-free survival (PFS), with the objective to assess the efficacy of biomarker-driven escalation of osimertinib therapy with a combination platinum-based regimen. Secondary outcome measures are the overall response rate (ORR), overall survival (OS), and the Quality of life (QLQ-C30, CTCAE-PROs) of the treated patients. In exploratory analyses, we will assess whether specific patterns of co-mutations are associated with early treatment failure (upon TKI) and pEGFR persistence. Fig. 1 illustrates the trial concept. A sample of 46 subjects achieves 80% power at a 0.05 significance level to detect a PFS of 14.4 months in the experimental treatment group when the PFS of the historic control group is 9.1 months; a total of 400 patients need to be screened within the national Network Genomic Medicine. Enrollment started in 12/2021. The clinical trial is supported by AstraZeneca and Guardant. EudraCT registration number: 2019-004757-88 .

HER-2, Hormone Receptors, and clinicopathologic characteristics in Uruguayan breast cancer patients

e22202

Background: Few Latin-American studies and none Uruguayan study have evaluated HER-2, estrogen receptor (ER) and progesterone receptor (PR) in breast cancer (BC). The purpose of the study was to investigate the frequency of these markers and the relationship between them and with clinicopathologic features in Uruguayan BC patients (pts). Methods: We retrospectively reviewed clinical records from pts who underwent curative surgery for stage I-III invasive BC at the Oncology Units of 4 institutions in Montevideo between march 2006 and march 2008. We obtained the following data: age, TNM, ER/PR status by immunohistochemistry (IHC) and HER2 status by IHC and FISH in HER2 IHC 2+. Fisher's exact test was used to analyze the data. Results: 427 pts were included. Median age was 60 years-old (range: 24–93 y), postmenopausal 75%, stages: I 33%, II 42%, III 23%, unknown 2%. ER/PR status was known in 94,6% of cases: ER+/PR+ 66,1%, ER+/PR- 11,1%, ER-/PR+ 3,5%, ER-/PR- 19,3%. HER2 status was known in 47% (199/427) of cases, being positive (IHC 3+ or FISH+) in 13.6%. Triple negative tumors were found in 32 of 199 pts (16%). HER2 was positive in 8% of pts with ER+ and/or PR+ tumors, and in 18% of pts with ER-PR- disease (p=0.08). We did not find a significant association between axillary lymph node status and HER2 status. Besides, triple negative BC did not correlate with axillary lymph node status. When analized by menopausal status, the frequency of triple negative pts was 14% in the premenopausal group and 4% in the postmenopausal group (p=0.005). In addition, the rate of triple negative BC was 0% in pts with histologic grade 1 and 10% in pts with histologic grade 2–3 (p = 0.0005). Conclusions: Our data from Uruguayan pts show a lower prevalence of HER2 positive but a similar prevalence of ER+ and PR+ operable BC than the prevalence reported in most American and European studies. In accordance with previous reports, triple negative BC correlated with younger age and higher histologic grade.

No significant financial relationships to disclose.