A phase 1 study evaluating rovalpituzumab tesirine in frontline treatment of patients with extensive-stage SCLC

INTRODUCTION: Rovalpituzumab tesirine (Rova-T) is an antibody-drug conjugate targeting DLL3, a Notch pathway ligand highly expressed on SCLC cells. Rova-T was evaluated alone or in combination with platinum-based chemotherapy (cisplatin or carboplatin combined with etoposide [CE]) in frontline treatment of extensive-stage SCLC. METHODS: One cycle of CE pre-enrollment was permitted (later mandated). The following four cohorts were enrolled: Rova-T monotherapy (0.3 mg/kg, every 6 [q6] wk × 2; cohort 1; n = 4); Rova-T induction (0.3 mg/kg, q6 wk × 2) followed by CE every 21 days (q21) × 4 (cohort 2; n = 5); Rova-T (0.1 or 0.2 mg/kg, q6 wk × 2) overlapping with CE q21 × 4 (cohort 3; n = 14); and Rova-T maintenance (0.3 mg/kg, q6 wk × 2) after CE q21 × 4 (cohort 4; n = 3). RESULTS: A total of 26 patients were dosed (cohort 3: 14; cohorts 1, 2, and 4 combined: 12). Median age was 66 years, and 73% had Eastern Cooperative Oncology Group performance status of 1. In cohort 3, seven patients (50%) had confirmed objective responses, with a median progression-free survival of 5.2 months and median overall survival of 10.3 months. Compared with cohorts 1, 2, and 4 combined, cohort 3 had lower frequency of some Rova-T-related adverse events of special interest, such as pleural effusion (0 versus 33%), pericardial effusion (0 versus 17%), ascites (0 versus 8%), peripheral edema (36% versus 42%), generalized edema (0 versus 8%), pneumonia (7% versus 25%), and hypoalbuminemia (0 versus 17%). CONCLUSIONS: Lower Rova-T doses may be associated with lower incidence of some Rova-T-related adverse events of special interest. Rova-T 0.2 mg/kg plus CE (cohort 3) was tolerable; however, there was no clear efficacy benefit of adding Rova-T to CE

A phase I/II study of rovalpituzumab tesirine in delta-like 3-expressing, advanced solid tumors.

Background: Delta-like 3 (DLL3) is highly and specifically expressed in solid tumors, such as neuroendocrine carcinomas (NECs), malignant melanoma (MM), and medullary thyroid carcinoma (MTC). Rovalpituzumab tesirine (Rova-T) is a DLL3-targeting antibody-drug conjugate. Methods: This Phase 1/2 study (NCT02709889) enrolled patients with relapsed/refractory DLL3+ (\u3e1% by IHC) advanced solid tumors and ECOG performance status of 0-1. Rova-T was given IV at 0.2, 0.3, or 0.4 mg/kg on d 1 of each 6-wk cycle (q6wk) for dose escalation (3+3 design) in disease-specific cohorts in Phase I. The recommended Phase 2 dose (RP2D) was tested in Phase II. Safety and dose-limiting toxicities (DLTs) were primary endpoints; efficacy outcomes were secondary endpoints. Results: The study enrolled 200 patients; 101 had NECs (large cell NEC [n=13], neuroendocrine prostate cancer [n=21], high-grade gastroenteropancreatic NEC [n=36], other [n=31]) and 99 had other solid tumors (MM [n=20], MTC [n=13], glioblastoma [GBM; n=23], other [n=43]). The median age was 61 y (range, 28-84); 63% were male. The RP2D was 0.3 mg/kg q6wk for 2 cycles in all cohorts. There were 7 DLTs in 5 patients: 2 with 0.2 mg/kg (Grade [Gr] 3 photosensitivity reaction, Gr 3 dyspnea), 2 with 0.3 mg/kg (1 with Gr 2 effusion, Gr 3 tumor lysis syndrome, and Gr 3 rhabdomyolysis; 1 with Gr 4 kidney injury), and 1 with 0.4 mg/kg (Gr 4 thrombocytopenia). Despite only 1 DLT identified with 0.4 mg/kg, the totality of the safety data suggested that this dose is not well tolerated. Common adverse events (AEs) in patients given 0.3 mg/kg (n=145) are shown (Table). Serious AEs occurred in 77/145 patients (53%), most commonly (≥3%) malignant neoplasm progression (n=18; 12%), pleural effusion (n=7; 5%), pericardial effusion (n=6; 4%), and dyspnea (n=5; 3%). The objective response rate (ORR) was 11% (21/200): 14 had NEC, 2 had MM, 2 had MTC, 2 had small cell carcinoma (SCC) not of lung origin (all partial responses), and 1 had GBM (complete response). In patients with NECs given 0.3 mg/kg, ORR, clinical benefit rate, and progression-free survival trended in favor of those with high DLL3-expressing tumors (≥50% by IHC) which represented 51% of NECs. Conclusions: Rova-T was tolerable in patients with advanced solid tumors at 0.3 mg/kg q6wk for 2 cycles. Antitumor activity was observed in patients with NEC, MM, MTC, SCC, and GBM. Clinical trial information: NCT02709889