Nivolumab and ipilimumab in recurrent or refractory cancer of unknown primary: a phase II trial.

Cancer of unknown primary has a dismal prognosis, especially following failure of platinum-based chemotherapy. 10-20% of patients have a high tumor mutational burden (TMB), which predicts response to immunotherapy in many cancer types. In this prospective, non-randomized, open-label, multicenter Phase II trial (EudraCT 2018-004562-33; NCT04131621), patients relapsed or refractory after platinum-based chemotherapy received nivolumab and ipilimumab following TMBhigh vs. TMBlow stratification. Progression-free survival (PFS) represented the primary endpoint; overall survival (OS), response rates, duration of clinical benefit and safety were the secondary endpoints. The trial was prematurely terminated in March 2021 before reaching the preplanned sample size (n = 194). Among 31 evaluable patients, 16% had a high TMB ( > 12 mutations/Mb). Overall response rate was 16% (95% CI 6-34%), with 7.7% (95% CI 1-25%) vs. 60% (95% CI 15-95%) in TMBlow and TMBhigh, respectively. Although the primary endpoint was not met, high TMB was associated with better median PFS (18.3 vs. 2.4 months) and OS (18.3 vs. 3.6 months). Severe immune-related adverse events were reported in 29% of cases. Assessing on-treatment dynamics of circulating tumor DNA using combined targeted hotspot mutation and shallow whole genome sequencing as part of a predefined exploratory analysis identified patients benefiting from immunotherapy irrespective of initial radiologic response.

Paclitaxel/carboplatin with or without belinostat as empiric first-line treatment for patients with carcinoma of unknown primary site: A randomized, phase 2 trial.

BACKGROUND: The objective of this study was to evaluate the efficacy of belinostat, a histone deacetylase inhibitor, when added to paclitaxel/carboplatin in the empiric first-line treatment of patients with carcinoma of unknown primary site (CUP). METHODS: In this randomized phase 2 trial, previously untreated patients with CUP were randomized to receive belinostat plus paclitaxel/carboplatin (group A) or paclitaxel/carboplatin alone (group B) repeated every 21 days. Patients were re-evaluated every 2 cycles, and those without disease progression continued treatment for 6 cycles. Patients in group A then continued receiving single-agent belinostat, whereas patients in group B stopped treatment. The primary endpoint was progression-free survival (PFS): The authors postulated that the addition of belinostat would improve PFS from 5 months (expected with paclitaxel/carboplatin) to 8 months. RESULTS: In total, 89 patients were randomized (group A, n = 44; group B, n = 45), and the demographics and disease characteristics were balanced between the 2 groups. The addition of belinostat to paclitaxel/carboplatin did not improve PFS (group A, 5.4 months [95% confidence interval, 3.0-6.0 months]; group B, 5.3 months [95% confidence interval, 2.8-6.6 months]; P = .85). Overall survival was 12.4 months for group A versus 9.1 months for group B (P = .20). The response rate favored the belinostat group (45% vs 21%; P = .02). Belinostat resulted in a modest increase in treatment toxicity. CONCLUSIONS: The addition of belinostat to paclitaxel/carboplatin did not improve the PFS of patients with CUP who were receiving first-line therapy, although the patients who received belinostat had a higher investigator-assessed response rate. Future trials in CUP should focus on specific subsets, defined either by the predicted tissue of origin or by the identification of targetable molecular abnormalities.

Metastases in the Absence of a Primary Tumor: Advances in the Diagnosis and Treatment of CUP Syndrome.

INTRODUCTION: The term cancer of unknown primary site (CUP) syndrome is used to describe malignancies in which a complete diagnostic work-up detects metastases in the absence of an identifiable primary tumor. METHODS: Based on a selective literature review, national and international guidelines, and the experience of the "Arbeitskreis CUP-Syndrom der Arbeitsgemeinschaft Internistische Onkologie der Deutschen Krebsgesellschaft" (CUP Syndrome Committee of the Medical Oncology Joint Working Group of the German Cancer Society), developments in the diagnosis and treatment of CUP syndrome are reported. RESULTS: Most patients diagnosed with CUP have an unfavorable prognosis, with a life expectancy of less than 12 months. Nevertheless, it is important to identify subsets of patients in whom specific treatment offers the chance of long-term survival or even full recovery. DISCUSSION: Only rigorous further development of diagnostic tools and treatment protocols will enable an improvement of the poor prognosis of patients with CUP syndrome. Specific molecular treatment strategies have shown promising results.

Carcinoma of Unknown Primary - an Orphan Disease?

Carcinoma of unknown primary (CUP) is an intriguing clinical finding that is defined as biopsy-proven metastasis from a malignancy in the absence of an identifiable primary site after a complete clinical work-up. CUP is a relatively common clinical entity, accounting for approximately 3-5% of all cancer diagnoses, and consists of a heterogeneous group of tumors that have acquired the capacity to metastasize before the development of a clinically evident primary lesion. Notable advances have been made over the past years in the treatment of well-defined clinical subgroups of CUP, such as women with peritoneal carcinomatosis and young adults with poorly differentiated carcinomas of midline distribution, but for the majority of patients, the prognosis still remains poor. In this review, we highlight recent advances in the diagnosis and treatment of patients with CUP syndrome, and emphasize the importance of identifying several favorable subsets of CUP, amenable to specific treatment options. In addition, we will point out novel diagnostic and therapeutic approaches which will hopefully improve both our understanding and the prognosis of this more or less neglected disease.