Afamitresgene autoleucel for advanced synovial sarcoma and myxoid round cell liposarcoma (SPEARHEAD-1): an international, open-label, phase 2 trial.

BACKGROUND: Afamitresgene autoleucel (afami-cel) showed acceptable safety and promising efficacy in a phase 1 trial (NCT03132922). The aim of this study was to further evaluate the efficacy of afami-cel for the treatment of patients with HLA-A*02 and MAGE-A4-expressing advanced synovial sarcoma or myxoid round cell liposarcoma. METHODS: SPEARHEAD-1 was an open-label, non-randomised, phase 2 trial done across 23 sites in Canada, the USA, and Europe. The trial included three cohorts, of which the main investigational cohort (cohort 1) is reported here. Cohort 1 included patients with HLA-A*02, aged 16-75 years, with metastatic or unresectable synovial sarcoma or myxoid round cell liposarcoma (confirmed by cytogenetics) expressing MAGE-A4, and who had received at least one previous line of anthracycline-containing or ifosfamide-containing chemotherapy. Patients received a single intravenous dose of afami-cel (transduced dose range 1·0 × 109-10·0 × 109 T cells) after lymphodepletion. The primary endpoint was overall response rate in cohort 1, assessed by a masked independent review committee using Response Evaluation Criteria in Solid Tumours (version 1.1) in the modified intention-to-treat population (all patients who received afami-cel). Adverse events, including those of special interest (cytokine release syndrome, prolonged cytopenia, and neurotoxicity), were monitored and are reported for the modified intention-to-treat population. This trial is registered at ClinicalTrials.gov, NCT04044768; recruitment is closed and follow-up is ongoing for cohorts 1 and 2, and recruitment is open for cohort 3. FINDINGS: Between Dec 17, 2019, and July 27, 2021, 52 patients with cytogenetically confirmed synovial sarcoma (n=44) and myxoid round cell liposarcoma (n=8) were enrolled and received afami-cel in cohort 1. Patients were heavily pre-treated (median three [IQR two to four] previous lines of systemic therapy). Median follow-up time was 32·6 months (IQR 29·4-36·1). Overall response rate was 37% (19 of 52; 95% CI 24-51) overall, 39% (17 of 44; 24-55) for patients with synovial sarcoma, and 25% (two of eight; 3-65) for patients with myxoid round cell liposarcoma. Cytokine release syndrome occurred in 37 (71%) of 52 of patients (one grade 3 event). Cytopenias were the most common grade 3 or worse adverse events (lymphopenia in 50 [96%], neutropenia 44 [85%], leukopenia 42 [81%] of 52 patients). No treatment-related deaths occurred. INTERPRETATION: Afami-cel treatment resulted in durable responses in heavily pre-treated patients with HLA-A*02 and MAGE-A4-expressing synovial sarcoma. This study shows that T-cell receptor therapy can be used to effectively target solid tumours and provides rationale to expand this approach to other solid malignancies. FUNDING: Adaptimmune.

Safety and Efficacy of the Combination Lurbinectedin plus Doxorubicin from a Phase 1b Trial in Patients with Advanced/Metastatic Soft-Tissue Sarcoma.

PURPOSE: While cytotoxic chemotherapy is the standard first-line treatment for patients with metastatic soft-tissue sarcoma (STS), clinical outcomes remain suboptimal. Our prior study showed lurbinectedin plus doxorubicin is well tolerated with promising clinical activity in STS. We designed this phase 1b trial to optimize dosing as the basis for a randomized trial in leiomyosarcoma and to further explore the safety profile and efficacy signal. PATIENTS AND METHODS: Patients had advanced/metastatic STS and no prior anthracycline/lurbinectedin/trabectedin. Escalation followed a 3 + 3 design with 3-week cycles: lurbinectedin (3.2 mg/m2 day 1) and two doxorubicin levels (DL1, 25 mg/m2 day 1; DL2, 25 mg/m2 days 1 and 8). The primary objectives were to identify the maximum tolerated dose and recommended dose for subsequent randomized trials. RESULTS: Ten patients were enrolled in a 6-month period. The most common treatment-emergent adverse events were grade (G) 2 fatigue and nausea, and G2 cytopenias with no febrile neutropenia events. There were two dose-limiting toxicities (DLTs) at DL2 [day 8 (G2 alanine aminotransferase [ALT]/aspartate aminotransferase increase, G3 neutropenia)], and one DLT in DL1 (G3 ALT increase). These were reversible and all patients continued the study. DL1 was chosen for further study. At the time of data cutoff, the estimated median progression-free survival is 16.5 months [95% confidence interval (CI), 6.0-ND]. The objective response rate was 60% (6/10 confirmed partial responses). CONCLUSIONS: In this phase 1b study, the recommended dose is lurbinectedin 3.2 mg/m2 in combination with doxorubicin 25 mg/m2 every 3 weeks. The study combination was well tolerated and demonstrated intriguing clinical activity.

Improving Collection and Analysis of Overall Survival Data.

Advances in anticancer therapies have provided crucial benefits for millions of patients who are living long and fulfilling lives. While these successes should be celebrated, there is certainly room to continue improving cancer care. Increased long-term survival presents additional challenges for determining whether new therapies further extend patients' lives through clinical trials, commonly known as the gold standard endpoint of overall survival (OS). As a result, there is an increasing reliance on earlier efficacy endpoints , which may or may not correlate with OS, to continue the timely pace of translating innovation into novel therapies available for patients. Even when not powered as an efficacy endpoint, OS remains a critical indication of safety for regulatory decisions and is a key aspect of the U.S. Food and Drug Administration's Project Endpoint. Unfortunately, in the pursuit of earlier endpoints, many registrational clinical trials lack adequate planning, collection, and analysis of OS data, which complicates interpretation of a net clinical benefit or harm. This article shares best practices, proposes novel statistical methodologies, and provides detailed recommendations to improve the rigor of using OS data to inform benefit-risk assessments, including incorporating the following in clinical trials intending to demonstrate the safety and effectiveness of a cancer therapy: prospective collection of OS data, establishment of fit-for-purpose definitions of OS detriment, and prespecification of analysis plans for using OS data to evaluate for potential harm. These improvements hold promise to help regulators, patients and providers better understand the benefits and risks of novel therapies.