Interim results of a phase II single arm trial combining afatinib with cetuximab in patients with EGFRex20ins positive NSCLC

9112

Background: Epidermal growth factor receptor exon 20 insertions (EGFRex20ins) are identified in 4-10% of all EGFR mutations in non-small cell lung cancer (NSCLC) and are associated with primary resistance to EGFR tyrosine kinase inhibitors (TKIs). Treatment options are limited. A case series showed that dual EGFR blockade with afatinib and cetuximab can induce tumor responses with manageable toxicity. We report on the first seventeen EGFRex20ins patients treated with afatinib in combination with cetuximab. Methods: In this Simon’s two stage, single-arm, phase II trial, patients with advanced NSCLC harboring an EGFRex20ins mutation were treated with afatinib 40 mg once daily, in combination with cetuximab 500 mg/m2, every two weeks, in five institutions in the Netherlands. Supportive medication consisted of minocycline, loperamide and skin creams. No previous line of treatment was required and asymptomatic brain metastases were allowed. The primary endpoint was disease control rate (DCR) after 18 weeks of treatment. Secondary endpoints included safety, response rate (RR), duration of response (DOR) and progression-free survival (PFS). Patients were treated until progression or unacceptable toxicity. A Simon’s two stage optimal design was used in order to minimize the number of patients being treated in the event that the regimen proves to be inactive. The estimated sample size of the first stage was 17 patients. At least four successes were required to enter stage 2 of the trial (alpha = 0.10; power = 0.90). Results: Eighteen patients were enrolled between Jan 2019 and Aug 2020; one patient did not meet the eligibility criteria due to absence of measurable disease. Median age was 66.0 years, 65% female, 53% never smoker. 47% of patients were treated as first-line therapy. Median prior lines of treatment was 1 (range 0-6). 53% received prior platinum-based chemotherapy. The primary endpoint was met as disease control was achieved by 10 patients (59%) after 18 weeks of treatment. Median PFS was 5.5 months. Best responses were partial (n = 8, RR 47%), stable (n = 7) or progressive disease (n = 2). Four patients were still on treatment at the cut-off date (Feb 2021). Most common treatment-related adverse events (TRAEs) were diarrhea (71%), rash (65%), paronychia (59%) and dry skin (53%). Grade III TRAEs were reported in 59% of all patients. Grade III TRAEs ≥ 10% included rash (n = 3; 18%) and diarrhea (n = 3; 18%). No grade IV toxicity was observed. One patient died due to respiratory failure after infusion of study medication, probably related to disease progression, possibly treatment related. 82% of patients required a dose reduction. Rate of treatment discontinuation due to AEs was 12% (n = 2). Conclusions: Combination treatment with afatinib and cetuximab demonstrated antitumor activity with a DCR of 59% at 18 weeks and a 47% RR, with manageable toxicity. Clinical trial information: NCT03727724.

A phase II basket study of MCLA-128, a bispecific antibody targeting the HER3 pathway, in NRG1 fusion-positive advanced solid tumors

TPS3654

Background: NRG1 fusions are oncogenic drivers across various cancers. NRG1 fusion proteins bind to HER3, leading to HER2/HER3 heterodimerization, increased downstream signaling, and tumor growth. Clinical responses to anti-HER3 antibodies or HER2 tyrosine kinase inhibitors have been reported. In contrast to these agents, MCLA-128 is a HER2/HER3 bispecific antibody that blocks both NRG1 binding and HER2/3 dimerization. Two patients with chemotherapy-resistant ATP1B1-NRG1-positive pancreatic KRAS-wild-type adenocarcinomas who received MCLA-128 through FDA-approved single-patient Investigational New Drug (IND) applications showed significant tumor shrinkage and durable tumor marker (CA-19-9) response. These data support the evaluation of MCLA-128 in NRG1 fusion-positive tumors using a basket approach. Methods: This is a global, open-label, multicenter phase 2 basket trial of MCLA-128 in patients with solid tumors harboring NRG1 gene fusions. Main eligibility criteria are locally advanced unresectable or metastatic cancers harboring an NRG1 fusion, and failure under prior standard therapy appropriate for the tumor type and disease stage. Genomic screening of tumor tissue is done at a local laboratory (with post-hoc central confirmation) or central laboratory (RNA sequencing). Three NRG1 fusion-positive tumor cohorts are being evaluated: pancreatic cancer, NSCLC, and other solid tumors. The sample size for the first two cohorts is up to 25 patients; the basket group may enroll up to 40 patients. The primary endpoint for all cohorts is investigator-assessed objective response rate (RECIST v1.1). The key secondary endpoint is duration of response. Other secondary endpoints include progression-free and overall survival. Eligible patients receive a bi-weekly dosing regimen of 750 mg of MCLA-128 (2-hour infusion), every 2 weeks, in 4-week cycles. The study is actively accruing patients in North America, Europe, and Asia. Previously presented at ESMO 2019, 685TiP, Schram et al.-Reused with permission. Clinical trial information: NCT02912949 .

Chemotherapy in KRAS-mutated chemotherapy naive non-small cell lung cancer patients: A phase III comparing cisplatin-pemetrexed with carboplatin-paclitaxel-bevacizumab: NVALT 22 (NCT02743923)

TPS9127

Background: In a retrospective analysis of KRAS mutated non-small cell lung cancer (NSCLC) patients response and progression free survival (PFS) to first line chemotherapy was better for carboplatin-paclitaxel-bevacizumab then other first line combinations (Mellema Lung Cancer, 2015:90:249-54). Methods: Trial Design: Multi-center open label randomized phase III study. After stratification for KRAS mutation (G12V versus G12C versus other), performance status (0-1 vs. 2) and brain metastasis (yes of no) patients will be 1:1 randomized to carboplatin-paclitaxel-bevacizumab or cisplatin-pemetrexed q3wks for up to six cycles. Continuation maintenance with bevacizumab and pemetrexed is allowed until progression. Study population: histologically or cytologically confirmed stage IIIB or stage IV KRAS mutated NSCLC patients who are eligible for platinum-based chemotherapy and are chemotherapy naïve. Previous anti-PD(L1) therapy for advanced disease is allowed (amendment 25.1.2018). Response will be assessed according to RECIST 1.1, CT scans will be made every 6 weeks until progression. Blood and archival tissue will be optionally collected for translational research. This may help to identify subgroups of patients who are likely better treated with a specific treatment regimen. Statistical analysis: The trial was designed to demonstrate superiority of the carboplatin-paclitaxel-bevacizumab treatment over cisplatin-pemetrexed with an assumed hazard ratio of 0.67. In total 201 events are required for the final analysis, corresponding to a total sample size of 240 patients to be accrued. There is a single interim analysis planned after 101 events have been observed. Primary endpoint: PFS defined by the response criteria in solid tumors (RECIST) and assessed by independent review. Secondary endpoints: Overall response rate, Overall Survival, outcome according to type of KRAS mutation, response assessed by CRABB criteria. Study progress: Currently 25 sites are open across the Netherlands and 170 of the 240 required patients are randomized (February 12, 2019). Clinical trial information: NCT02743923.

Whole body PD-L1 PET in patients with NSCLC and melanoma

139

Background: PD-(L)1 immunotherapy is effective in multiple tumors, including NSCLC and melanoma, but tumor PD-L1 IHC correlates only moderately with treatment outcome. This study aims to assess 1) safety of 18F-BMS-986192 (18F-PD-L1) in human, 2) PD-L1 quantification in tumors using 18F-PD-L1 PET, 3) PD-L1 PET correlation with IHC and treatment outcome, and 4) intra and inter subject tracer uptake variability. Methods: Pts with NSCLC (N = 10) and melanoma (N = 3) were included. At baseline, pts received a static or multiphase dynamic whole body PET scan after injecting 200 MBq 18F-BMS-986192. For NSCLC pts, (1) SUV(max, peak and mean) were measured for each delineable tumor (N = 32, 1-7 tumors/pt), (2) PD-L1 IHC (28.8 assay) was performed on the biopsy, and (3) response to Nivolumab therapy assessed by RECIST 1.1. Intra and inter subject variability and intraclass correlation were calculated using SUVs of all assessed tumors. Equal variance for PD-L1 status was evaluated by a Levene’s test. Four (3 female) pts underwent dosimetry study (ICRP 60). Results: No AEs related to radiotracer was observed. Dosimetry study demonstrated whole body exposure of 30 mGy at dose > 1400 MBq. Biodistribution among pts is comparable. PD-L1 IHC from 13 biopsied lesions were evaluated, 5 < 1%, 4 ≥1%, and 4 ≥50%. Tumor tracer uptake was measured in NSCLC pts and categorized by PDL-1 IHC as ≥50% or < 50%. Clinical trial information: 2015-004760-11. Tumor SUVs did not correlate with RECIST 1.1 assessment. Lesion heterogeneity was reflected in both inter and intra pt variability (CVinter = 41%, CVintra = 53%, ICC = 0.41 for SUVpeak). Levene’s test showed no significance in variability between the two PD-L1 categories. Conclusions: PET-imaging with 18F-BMS-986192 is safe and feasible in pts with NSCLC and melanoma. Pts with higher PD-L1 PET SUV have higher PD-L1 by IHC. Intra pt variability is similar to inter pt variability. With limited number of pts, no clear correlation of PET PD-L1 and tumor response is observed. A prospective study with this tracer is underway to further investigate 18F-BMS-986192 in understanding of PD-L1 expression.[Table: see text]

Trastuzumab and paclitaxel in patients (pts) with EGFR mutated non-small-cell lung cancer (NSCLC) that express HER2 after progression on EGFR TKI treatment

9042

Background: HER2 expression as well as amplification has been well recognized in tumor biopsies of pts with an EGFR mutation who developed EGFR TKI resistance. It is unknown whether HER2 targeting in this setting can result in tumor responses. Methods: Single arm open label phase II study to study the safety and efficacy of paclitaxel-trastuzumab treatment in pts with a sensitizing EGFR mutation who show tumor membrane HER2 expression in a tumor biopsy (immunohistochemistry (IHC) ≥1) after progression on EGFR TKI treatment. Paclitaxel (60 mg/m2) and trastuzumab (first dose 4 mg/kg, thereafter 2 mg/kg) were dosed weekly until disease progression or unacceptable toxicity. Primary end-point was tumor response according to RECIST. Sample size of 20 pts was calculated to evaluate the primary objective of ≥30% objective response rate. The study was deemed positive when ≥7 pts would show a partial or complete response. Results: 21 pts were enrolled from 08-2012 to 02-2017. 7 pts were exon 21 L858R positive and 14 exon 19 del. Last TKI was erlotinib (n = 6), gefitinib (n = 4), rociletinib (n = 3) or osimertinib (n = 8). Median HER2 IHC was 2+ (range 1-3). 17 pts were evaluable for response assessment, while 4 pts are awaiting their first response scan. The primary end-point was met with 7/17 pts (41%) showing a partial response. 2 pts showed stable disease, 7 progressive disease and 1 pt had clinical progression before CT response evaluation. Median duration of response was 9 (range 6-18) months with one ongoing responder. 3 pts experienced grade ≥3 toxicity, including fatigue, neuropathy and neutropenia. Upon progression on study treatment, all responding pts were rebiopsied. 4/6 samples were negative for HER2 (IHC), suggesting that the combination effectively targeted HER2 positive tumor cells. Conclusions: The study met its primary end-point. Paclitaxel-trastuzumab induces durable objective tumor responses in EGFR TKI pretreated pts with an activating EGFR mutation and HER2 bypass track activation. The treatment was well tolerated. Post-progression tumor biopsies showed absence of HER2 staining in the majority of pts, suggesting effective HER2 targeting. Clinical trial information: NCT02226757.

Whole body PD-1 and PD-L1 PET with 89Zr-nivolumab and 18F- BMS-986192 in pts with NSCLC

e20047

Background: Tumor PD-L1 IHC relates moderately with treatment outcome following anti-PD-(L)1 monotherapy in pts with NSCLC. Aim: 1. To assess safety of the PET procedures. 2. To quantify PD-1 and PD-L1 expression in tumors with 89Zirconium-labeled nivolumab (89Zr-nivo) and 18F-labeled BMS-986192 (18F-PD-L1) PET. 3. To assess intra- and inter-patient tracer uptake differences in tumors. 4. To correlate PET results with IHC and treatment outcome. Methods: NSCLC pts eligible for treatment with nivolumab were included. Pts received a dynamic and static whole body 18F-PD-L1 and a static 89Zr-nivo PET scan. A baseline tumor biopsy was required and up to two additional biopsies were allowed in case PET showed heterogeneous tumor uptake. SUVpeak was calculated for all delineable tumor lesions and related to PD-(L)1 IHC (28.8 assay) and response after 6 wks of nivolumab treatment. Results: 7 pts (5 ≥1%, 2 ≥50% and 2 negative by PD-L1 IHC) were enrolled and 11 lesions analyzed. No toxicity related to radiotracer administration was identified. Tumor uptake of both tracers was visualized in all pts. There was substantial variability among pts for 18F-PD-L1 (mean SUV 5.4, range 2.2 - 14.4) and 89Zr-nivo (mean SUV 5.0, range 1.6 - 9.7). Intra-patient tracer uptake heterogeneity was also seen: mean 2.5-fold (±0.96) and 2.3-fold (±0.86) differences between lesions for 18F-PD-L1 and 89Zr-nivo SUV, respectively. For lesions with < 50% PD-L1 IHC mean 18F-PD-L1 SUV was 3.4 (±2.9) as compared to 7.1 (±6.0) for lesions with ≥50% PD-L1 IHC (p = 0.22). For lesions with low PD-1 expression mean 89Zr-nivo SUV was 6.9 (±2.7) as compared to 8.1 (±2.0) for lesions with high PD-1 expression (p = 0.44). Five pts were evaluable for response evaluation: 1 PR, 2 SD and 2 PD with 18F-PD-L1 SUV values (most PET avid lesion) of 14.4 (PR), 2.0 and 5.4 (SD) and 6.4 and 6.6 (PD). Conclusion: 1.PET-imaging with both tracers is safe and feasible, with good tumor-to-normal tissue contrast. 2. Tumor uptake demonstrated substantial heterogeneity among pts and among tumors within the same pts. 3. Although higher 18F-PD-L1 tumor uptake was seen in pts with ≥50% tumor PD-L1 IHC and the highest 18F-PD-L1 SUV was measured in the responding pt, the dataset is still very small. Clinical trial information: 2015-004760-11.