Measuring Toxic Effects and Time to Treatment Failure for Nivolumab Plus Ipilimumab in Melanoma.

IMPORTANCE: Nivolumab plus ipilimumab (nivo + ipi) is a standard treatment of advanced melanoma. Two randomized trials describe high objective response rates by Response Evaluation Criteria in Solid Tumors. The trials assessed toxic effects using the Common Terminology Criteria for Adverse Events (CTCAE), which may underestimate incidence of clinically significant immune-related adverse events (AEs). OBJECTIVE: To describe detailed toxic effects and time to treatment failure of patients with melanoma treated with nivo + ipi in a prospective cohort. DESIGN, SETTING, AND PARTICIPANTS: A cohort of 64 adults with advanced or unresectable melanoma were examined at a single tertiary cancer and enrolled in an expanded access program of nivo + ipi conducted from December 2014 to January 2016. INTERVENTIONS: Intravenous nivolumab (1 mg/kg) and ipilimumab (3 mg/kg) administered every 3 weeks for up to 4 doses, followed by nivolumab (3 mg/kg) every 2 weeks or pembrolizumab (2 mg/kg) every 3 weeks until unacceptable toxic effects, disease progression, or complete response. MAIN OUTCOMES AND MEASURES: Clinically significant immune-related AEs were defined as CTCAE grade 2 or higher or any immune-related AEs requiring systemic steroids. Time to treatment failure was defined as the interval between initiating therapy and the earliest of clinical progression, new locally directed or systemic treatment other than anti-programmed cell death 1 protein (anti-PD-1) monotherapy, or death. RESULTS: Overall 64 adults with advanced or unresectable melanoma were enrolled (male to female ratio, 1:1; median [range] age, 56 [22-82] years); 25 patients (39%) received all 4 doses of nivo + ipi, and 31 patients (48%) received no maintenance anti-PD-1 therapy. Most who discontinued treatment (n = 31 [80%]) stopped because of toxic effects. Among those patients who were progression free at 12 weeks, time to treatment failure was similar between those who did or did not modify therapy for toxic effects. Fifty-eight patients (91%) had a clinically significant immune-related AE (median, 2/patient), and 46 patients (72%) required systemic steroids. Infliximab or mycophenolate was required in 16 patients (25%) for steroid-refractory immune-related AEs. Seven patients (11%) developed hyperglycemia, 32 patients (50%) had an emergency department visit, and 23 patients (36%) required a hospital admission related to an immune-related AE. Four of 31 patients (13%) who stopped combination therapy early for toxic effects developed a new, clinically significant immune-related AE more than 16 weeks after the last treatment. CONCLUSIONS AND RELEVANCE: We observed a 91% incidence of clinically significant immune-related AEs leading to frequent emergency department visits, hospitalizations, and systemic immunosuppression. Immuno-oncology trials should routinely report these metrics. Most patients do not tolerate 4 doses of nivo + ipi; however, 4 doses may not be required for clinical benefit.

Activation of the Chicken Anemia Virus Apoptin Protein by Chk1/2 Phosphorylation Is Required for Apoptotic Activity and Efficient Viral Replication.

UNLABELLED: Chicken anemia virus (CAV) is a single-stranded circular DNA virus that carries 3 genes, the most studied of which is the gene encoding VP3, also known as apoptin. This protein has been demonstrated to specifically kill transformed cells while leaving normal cells unharmed in a manner that is independent of p53 status. Although the mechanistic basis for this differential activity is unclear, it is evident that the subcellular localization of the protein is important for the difference. In normal cells, apoptin exists in filamentous networks in the cytoplasm, whereas in transformed cells, apoptin is present in the nucleus and appears as distinct foci. We have previously demonstrated that DNA damage signaling through the ataxia telangiectasia mutated (ATM) pathway induces the translocation of apoptin from the cytoplasm to the nucleus, where it induces apoptosis. We found that apoptin contains four checkpoint kinase consensus sites and that mutation of either threonine 56 or 61 to alanine restricts apoptin to the cytoplasm. Furthermore, treatment of tumor cells expressing apoptin with inhibitors of checkpoint kinase 1 (Chk1) and Chk2 causes apoptin to localize to the cytoplasm. Importantly, silencing of Chk2 rescues cancer cells from the cytotoxic effects of apoptin. Finally, treatment of virus-producing cells with Chk inhibitor protects them from virus-mediated toxicity and reduces the titer of progeny virus. Taken together, our results indicate that apoptin is a sensor of DNA damage signaling through the ATM-Chk2 pathway, which induces it to migrate to the nucleus during viral replication. IMPORTANCE: The chicken anemia virus (CAV) protein apoptin is known to induce tumor cell-specific death when expressed. Therefore, understanding its regulation and mechanism of action could provide new insights into tumor cell biology. We have determined that checkpoint kinase 1 and 2 signaling is important for apoptin regulation and is a likely feature of both tumor cells and host cells producing virus progeny. Inhibition of checkpoint signaling prevents apoptin toxicity in tumor cells and attenuates CAV replication, suggesting it may be a future target for antiviral therapy.