Efficacy and safety of cosibelimab, an anti-PD-L1 antibody, in metastatic cutaneous squamous cell carcinoma.

BACKGROUND: Programmed cell death receptor-1 (PD-1)-blocking antibodies are approved to treat metastatic or locally advanced cutaneous squamous cell carcinoma (CSCC) cases ineligible for curative surgery or radiation. Notwithstanding, some patients experience inadequate responses or severe immune-related adverse events (AEs), indicating the need for improved therapies. Cosibelimab is a high-affinity programmed cell death-ligand 1 (PD-L1)-blocking antibody that activates innate and adaptive immunity by blocking PD-L1 interaction with PD-1 and B7-1 receptors. It is an unmodified immunoglobulin G1 subtype with a functional Fc domain capable of inducing antibody-dependent cellular cytotoxicity and complement-dependent cytotoxicity. Here, we present results of the pivotal study of patients with metastatic CSCC from an open-label, multicenter, multiregional, multicohort, phase 1 trial of cosibelimab. METHODS: In this trial, participants with metastatic CSCC received cosibelimab 800 mg intravenously every 2 weeks. Primary endpoint was objective response rate (ORR) by independent central review using Response Evaluation Criteria in Solid Tumors, V.1.1. Secondary endpoints included duration of response (DOR) and safety. RESULTS: Objective response was observed in 37 of 78 participants (47.4% (95% CI: 36.0% to 59.1%)), with median follow-up of 15.4 months (range: 0.4 to 40.5) as of data cut-off. Median DOR was not reached (range: 1.4+ to 34.1+ months), with response ongoing in 73.0% of participants. Common treatment-emergent AEs (≥15%) were fatigue (26.9%), rash (16.7%), and anemia (15.4%). Eighteen participants (23.1%) experienced immune-related AEs (grade 3: n=2 (2.6%); no grade 4/5). No treatment-related deaths were reported. CONCLUSIONS: Cosibelimab demonstrated clinically meaningful ORR and DOR and was associated with a manageable safety profile. TRIAL REGISTRATION NUMBER: NCT03212404.

Serious hepatic complications of selective internal radiation therapy with yttrium-90 microsphere radioembolization for unresectable liver tumors.

AIM: Selective internal radiation therapy with yttrium-90 microsphere radioembolization has been used to treat unresectable liver tumors and its acute toxicity has been well described. Subacute and long-term hepatic complications related to radioembolization however may be underreported in the literature. This retrospective study describes the incidence and sequelae of serious hepatic complications in patients who underwent radioembolization for unresectable liver tumors. METHODS: A retrospective review of clinical notes of patients who received radioembolization for unresectable liver tumors from 2001 to 2011 at two Australian institutions was performed to identify those who developed clinically significant hepatic complications. Relevant clinical data were obtained and analyzed to determine their incidence and sequelae. RESULTS: A total of 205 patients were identified, of whom 10 (4.9%) developed serious hepatic complications with 7 (3.4%) attributable to radioembolization-induced liver disease. None had preexisting underlying liver disease or progressive hepatic metastases at the time of developing hepatic complication. The median time to the onset of hepatic complications was 3.5 months (range 1-67 months); six patients had a complete resolution eventually, including one patient who subsequently underwent hepatic metastasectomy safely. Three patients died as a result of fulminant hepatic failure. CONCLUSION: Selective internal radiation therapy with radioembolization was associated with serious hepatic complications with an incidence of 4.9% and a mortality rate of 1.5% in 205 patients from two Australian institutions. The risk of serious hepatic toxicity therefore needs to be discussed when counseling patients regarding this potential treatment option.

Comparison of clinical and immunological effects of intravenous and intradermal administration of α-galactosylceramide (KRN7000)-pulsed dendritic cells.

PURPOSE: Human Vα24+Vß11+ natural killer T-cells (NKT cells) have antitumor activity via direct cytotoxicity and by induction of antitumor actions of T and NK cells. Activation of NKT cells is crucial for their antitumor activity and is induced by α-galactosylceramide (α-GalCer, KRN7000) presented by CD1d on dendritic cells (DC). We conducted a phase I clinical trial of therapy with α-GalCer-pulsed DC to determine safety, tolerability, immune effects and an optimal dose, and administration route. EXPERIMENTAL DESIGN: Twelve subjects (3 cohorts) with metastatic malignancy received 4 treatments of α-GalCer-pulsed DC, 2 treatments intravenously (IV), and 2 treatments intradermally (ID). Each successive cohort received a log higher cell dose. Clinical and immunological outcomes were evaluated, including secondary effects on NK and T cells. RESULTS: Substantial effects on peripheral blood NKT cells were observed but were greater following IV treatment. Secondary immune effects including activation of T and NK cells, increases in T- and NK-cell cytoplasmic interferon-γ, and increases in serum interferon-γ levels were seen after IV but not after ID treatment. Therapy was well tolerated, but 9 of 12 subjects had tumor flares with clinical findings consistent with transient tumor inflammation. Disease response (minor) or stabilization of disease progressing up to enrollment was observed in 6 of the 12 subjects. Stabilization of previously progressive disease lasted for at least one year in three subjects. CONCLUSION: We conclude that therapy with α-GalCer-pulsed DC induced clinically beneficial immune responses that are highly dependent on cell dose and administration route.

Therapeutic activation of Valpha24+Vbeta11+ NKT cells in human subjects results in highly coordinated secondary activation of acquired and innate immunity.

Human Valpha24+Vbeta11+ natural killer T (NKT) cells are a distinct CD1d-restricted lymphoid subset specifically and potently activated by alpha-galactosylceramide (alpha-GalCer) (KRN7000) presented by CD1d on antigen-presenting cells. Preclinical models show that activation of Valpha24+Vbeta11+ NKT cells induces effective antitumor immune responses and potentially important secondary immune effects, including activation of conventional T cells and NK cells. We describe the first clinical trial of cancer immune therapy with alpha-GalCer-pulsed CD1d-expressing dendritic cells. The results show that this therapy has substantial, rapid, and highly reproducible specific effects on Valpha24+Vbeta11+ NKT cells and provide the first human in vivo evidence that Valpha24+Vbeta11+ NKT cell stimulation leads to activation of both innate and acquired immunity, resulting in modulation of NK, T-, and B-cell numbers and increased serum interferon-gamma. We present the first clinical evidence that Valpha24+Vbeta11+ NKT cell memory produces faster, more vigorous secondary immune responses by innate and acquired immunity upon restimulation.