In SCCA (squamous cell carcinoma of anus) about 15% of patients are diagnosed in metastatic stage, and around 25-40% of patients will experience disease progression after curative intent chemoradiotherapy (CRT) for localized disease. In patients with non-resectable local recurrences or with distant metastases, the systemic chemotherapy is the standard approach. Recently, taxane-based combination chemotherapy regimens have demonstrated high efficacy or better tolerance than non-taxane based regimens, and became standards based in prospective trials. First, the modified DCF (docetaxel, cisplatin and 5-fluorouracil) showed a high efficacy in Epitopes-HPV02 trial conducted by investigators including 66 patients and became the first validated chemotherapy regimen in advanced SCCA. Then, the pooled analysis of 115 patients confirmed the mDCF regimen as the standard treatment in all fit patients with advanced SCCA.~The combination of different chemotherapy regimens and an anti-PD1/PD-L1 (Programmed cell Death-1/Programmed cell Death-Ligand1) were feasible with improved survival in first-line advanced small-cell and non-small-cell lung cancers. In anal carcinoma, Epitopes-HPV02 trial showed that mDCF regimen was feasible with 53% of grade 3-4 adverse-event, with no grade 4 non-hematological toxicity and no febrile neutropenia. And also considering its property to enhance the anti-tumor immune response, mDCF was recommended as an interesting candidate to be evaluated as a backbone chemotherapy for immunotherapy combinations in SCCA.~In anal carcinoma, investigators are currently conducting a randomized prospective trial promoted by GERCOR (cooperator group) evaluating the association of mDCF and an anti-PD-L1 in metastatic setting. All patients (100) were already enrolled, and no particular safety alert signal was observed at the Data Safety Monitoring Board (DSMB)..~Among different factors that confers a primary resistance to immunotherapy, the lack of antigenic proteins capable to induce immune response, and the downregulation of major histocompatibility complex class 1 (MHC-1) are probably the most important. In fact, the next-generation sequencing (NGS) techniques has demonstrated the correlation between tumor mutation burden (TMB) and response to CKI (checkpoint Inhibitor). Hence, most of hot tumors with high TMB could be treated with CKI alone, while cold tumors probably need combination strategies. Besides, primary or secondary resistances to CKI caused by downregulation of MHC-1 are well described.~Radiation causes random point mutations and double-stranded breaks in the DNA and modulates the peptide repertoire, increasing tumour-related antigens and TMB to enhance anti-tumour immunity. Radiotherapy has also demonstrated to enhances MHC class I expression.~Investigators decided to associate radiotherapy, PD-1 (Programmed cell Death-1) inhibitor and mDCF (docetaxel, cisplatin and 5-fluorouracil) chemotherapy regimen to improve the efficacy with higher rate of long-lasting progression-free survivors and complete remissions. In addition, the associated extensive ancillary biomarker studies in tissues and peripheral blood will provide a unique opportunity to find out the potential synergic effect mechanism between mDCF, CKI and radiotherapy, as well as to improve our knowledge about underlying resistances.
This study evaluates the feasibility of the combination of radiotherapy, chemotherapies (docetaxel, cisplatin and 5-fluorouracil) and spartalizumab (anti-PD-1 therapy) in patients with metastatic squamous cell anal carcinoma