Perianal thrombosis: no need for surgery.

AIM: There is little evidence for the best therapy for perianal thrombosis. No prospective trials exist. Even quality of retrospective data is low, due to low patient numbers or vague follow-up data. PATIENTS AND METHODS: Six hundred nineteen patients with thrombosis of internal or external hemorrhoids who presented in our clinic between March 2017 and August 2018 were enrolled in the study. All patients were treated conservatively, with sitz baths and oral pain medication, if needed. No surgery was performed. Follow-up data was obtained by personal examination. Data was gathered prospectively, and data analysis was retrospective. RESULTS: Five hundred four patients had perianal thrombosis (81.4%), and 115 patients had thrombosed hemorrhoids. Mean pain on a numerical rating scale (0-10) was 3.8 for perianal thrombosis and 5.2 for thrombosed hemorrhoids. Five hundred forty-eight patients (88.5%) did not need a sick leave. On follow-up, patients stated that their pain had largely resolved after 5 days and completely disappeared after 10 days. Local recurrence rate after perianal thrombosis was 6.3%. CONCLUSION: Perianal thrombosis and thrombosed hemorrhoids heal well without surgery. There is no evidence for advantages surgical therapy could offer.

Engineering a single-chain variable fragment of cetuximab for CAR T-cell therapy against head and neck squamous cell carcinomas.

The monoclonal antibody cetuximab recognizes domain III of the epithelial growth factor receptor (EGFR) with high-affinity and is an important element in the treatment of several malignancies that overexpress non-mutated wild-type EGFR. In order to create an EGFR recognizing chimeric antigen receptor (CAR) for cellular immunotherapy of head and neck squamous cell carcinoma (HNSCC), we rationally designed single chain fragments of different lengths based on the cetuximab variable heavy and light chains. We then cloned the different cetuximab fragments into our second generation CAR construct, expressed CARs on primary human T-cells from healthy donors using mono- or biscistronic lentiviral vectors and tested the stability, functionality and specificity of the CARs. Our smallest CAR construct was most efficient with greatly improved vector production and T-cell transduction efficacy. Finally, we demonstrated that the new cetuximab CAR construct expressed on T-cells is highly reactive against EGFR-positive HNSCCs and also malignant cells from other solid cancer entities. In conclusion, we generated an optimized high-affinity EGFR CAR construct for the next steps in cancer immunotherapy, which need to focus on the development of armored CAR T-cells that will be more resistant and effective in the hostile microenvironment present in solid cancers.

CD44v6-targeted CAR T-cells specifically eliminate CD44 isoform 6 expressing head/neck squamous cell carcinoma cells.

Immune checkpoint blockade can cause regression of recurrent and/or refractory head and neck squamous cell carcinoma (HNSCC). As a second type of immunotherapy, adoptive cellular therapy with genetically modified patient's T-cells redirected against the autologous malignant cells by expressing chimeric antigen receptors (CARs) recognizing tumor-associated antigens has been established as highly efficient personalized treatment for hematological malignancies. In solid cancers however, the application of these genetically modified immune effector cells still lacks equal response rates. CD44v6 is an isoform of the hyaluronic receptor CD44 that is almost exclusively expressed at high levels on solid cancers and has been associated with tumorigenesis, tumor cell invasion and metastasis. Here, we established a highly specific CAR against CD44v6 on HNSCC cells that can be expressed on normal T-cells with lentiviral vectors. Using primary human HNSCC cells in combination with CRISPR/Cas9 and overexpression approaches allowed us to confirm the high specificity of our CAR construct for the tumor-associated CD44v6 as target antigen and to demonstrate a direct correlation between CD44v6 expression levels and cytotoxicity of the CAR T-cells. Importantly, the design of our clinically applicable lentiviral vector facilitates to co-express a second transgene for in vivo control of CAR T-cells, if undesired side-effects or toxicities occur.