Viteri, Santiago

9068 Background: The phase 2 SUMMIT basket trial (NCT01953926) demonstrated efficacy of neratinib in patients with EGFR exon 18-mutant NSCLC [Boni et al. WCLC 2020]. Neratinib also has documented activity in HER2+ metastatic breast cancer with CNS metastases [Saura et al. SABCS 2020 & J Clin Oncol 2020]. Here we report neratinib efficacy in a subgroup of patients with EGFR exon 18-mutant NSCLC and CNS involvement from SUMMIT. Methods: Patients with EGFR exon 18-mutant NSCLC were treated with single-agent neratinib (240 mg po daily). Prior EGFR tyrosine kinase inhibitors (TKIs), chemotherapy, and checkpoint inhibitors (IO) were allowed. Patients with stable, asymptomatic CNS metastasis were enrolled. Study endpoints: objective response rate (ORR) at week 8 (±1 week); ORR (RECIST 1.1 confirmed); duration of response (DOR); clinical benefit rate (CBR); progression-free survival (PFS); safety; biomarkers. Results: Baseline characteristics of 11 patients with EGFR exon 18-mutant NSCLC: median age 67 (range 56–83) years; ECOG PS 0/1 (45%/55%). Prior lines of therapies: 2 (range 1–3): EGFR TKIs (91%); chemotherapy (55%); IO (27%). 3/11 patients had baseline CNS metastasis and received radiation 8–22 months prior to study enrollment. Best CNS response in these 3 patients was stable disease with overall individual PFS of 1.9 (censored), 6.9 and 9.1 months and OS of 2.6 (censored), 17.7 (censored), and 17.9 months. Efficacy is summarized in Table. Efficacy summary: TKI-pretreated EGFR exon 18-mutant NSCLC cohort receiving neratinib monotherapy. Conclusions: Activity of single-agent neratinib was observed in prior TKI-exposed patients with EGFR exon 18-mutant NSCLC. Despite the small sample size of only 3 patients with baseline CNS metastases, findings suggest a potential role for neratinib as a systemic treatment option for patients with NSCLC and difficult-to-treat uncommon mutations with CNS involvement. The SUMMIT trial continues to enroll patients with EGFR exon 18-mutant NSCLC. Clinical trial information: NCT01953926. [Table: see text]

320 Background: Genomic profiling studies have reported somatic HER2 mutations in ~2–5% of biliary tract cancers (BTC). Clinical data from the SUMMIT study demonstrate that neratinib, a pan-HER irreversible tyrosine kinase inhibitor, has encouraging clinical activity in multiple types of HER2-mutant solid tumor malignancies. Methods: SUMMIT is a multi-histology, open-label, phase II ‘basket’ study of neratinib in patients with somatic HER2 mutations (ClinicalTrials.gov NCT01953926). Patients with activating somatic HER2 mutations with different histologies, including BTC, received neratinib monotherapy (240 mg oral daily). Loperamide prophylaxis was mandatory during cycle 1. Efficacy endpoints: objective response rate (ORR, RECIST v1.1); clinical benefit rate (CBR); duration of response; progression-free survival (PFS). Adverse events (AEs) were assessed by CTCAE v4.0. Genomic profiling from fresh/archival tumor tissues and/or plasma cfDNA was performed retrospectively by next-generation sequencing (MSK-IMPACT). Results: As of 3-Sep-2020, 25 patients with HER2-mutant BTC were enrolled: gallbladder (40%); intrahepatic (24%); extrahepatic (20%); ampulla of Vater (16%). 68% of patients received ≥2 systemic regimens (96% received prior gemcitabine-based regimens). The S310F/Y variant accounted for nearly half of HER2 mutations (n=11). Other HER2 mutations: V777L (n=5); L755S (n=2); V842I (n=2); R678Q (n=2). Confirmed ORR in 25 evaluable patients was 12% (95% CI 3–31%) and CBR was 20% (95% CI 7–41%), including 3 confirmed PRs and 2 patients with SD for ≥16 weeks. Tumor shrinkage was observed in multiple HER2-activating mutations and enriched in gallbladder and extrahepatic subtypes of BTC. Median PFS was 2.8 (95% CI 1.1–3.7) months; median overall survival (OS) was 5.4 (95% CI 3.7–11.7) months. Nine (36%) patients (3 of whom with ECOG PS 2) came off study within 28 (range 6–47) days of treatment due to clinical deterioration (unrelated to study drug) followed by death. The most common treatment-related AEs (any grade) were diarrhea (56%) and vomiting (48%). Diarrhea was the most common Grade 3 event (24%); 4 patients (16%) required a neratinib dose reduction; no patients discontinued treatment due to diarrhea. Conclusions: Neratinib is safe and tolerable in patients with advanced BTC patients and somatic HER2 mutations. The antitumor activity of neratinib appears comparable to current standards of care, with similar PFS and OS in heavily pretreated patients. Analysis of co-occurring oncogenic mutations and response is ongoing, and consideration is being given to neratinib-based combination regimens to further improve outcomes in this setting. Clinical trial information: NCT01953926.

e20502 Background: The CNS is often a site of first disease progression in CRZ-treated ALK+ NSCLC. The ALTA trial is assessing BRG, an investigational next-generation ALK inhibitor, in pts with CRZ-refractory advanced ALK+ NSCLC, including pts with baseline brain metastases. Methods: In ALTA (NCT02094573), pts were stratified by presence of baseline brain metastases and best response to prior CRZ and randomized 1:1 to receive BRG at 90 mg qd (arm A) or 180 mg qd with a 7-d lead-in at 90 mg (arm B). Here, we show data for pts with baseline brain metastases. An independent review committee (IRC) assessed intracranial efficacy. Results: Of 222 pts (112 in arm A; 110 in arm B), 80 (71%)/74 (67%) in A/B had baseline brain metastases per investigators, with median age 49/55 y; 74%/76% had received chemotherapy. As of May 31, 2016, 51%/59% of these pts continued to receive BRG in A/B; median follow-up was 9.6/11.4 mo. Intracranial efficacy is shown in the table. Among these pts, most common treatment-emergent adverse events were: nausea 35%/46% (A/B), headache 30%/31%, vomiting 29%/31%, diarrhea 21%/38%, cough 25%/32%; grade ≥3: increased blood CPK 1%/12%, hypertension 4%/7%, increased lipase 4%/3%. Conclusions: BRG yielded substantial intracranial responses with robust iPFS and acceptable safety in ALK+ NSCLC pts with baseline brain metastases in ALTA. 180 mg (with lead-in) showed consistently improved intracranial efficacy compared with 90 mg. Clinical trial information: NCT02094573. [Table: see text]