Summary Haemato‐oncological patients are at risk in case of severe acute respiratory syndrome coronavirus‐2 (SARS‐CoV‐2) infection. Currently, vaccination is the best‐evaluated preventive strategy. In the present study, we aimed to assess serological response, predictive markers, and safety of BNT162b2 in haemato‐oncological patients. A total of 259 haemato‐oncological patients were vaccinated with two 30 µg doses of BNT162b2 administered 21 days apart. Serological response was assessed by ELECSYS® Anti‐SARS‐CoV‐2‐S immunoassay before vaccination, and at 3 and 7 weeks after the first dose (T1, T2). Safety assessment was performed. At T2 spike protein receptor binding domain (S/RBD) antibodies were detected in 71·4% of haematological and in 94·5% of oncological patients (P < 0·001). Haematological patients receiving systemic treatment had a 14·2‐fold increased risk of non‐responding (95% confidence interval 3·2–63·3, P = 0·001). Subgroups of patients with lymphoma or chronic lymphocytic leukaemia were at highest risk of serological non‐response. Low immunoglobulin G (IgG) level, lymphocyte‐ and natural killer (NK)‐cell counts were significantly associated with poor serological response (P < 0·05). Vaccination was well tolerated with only 2·7% of patients reporting severe side‐effects. Patients with side‐effects developed a higher S/RBD‐antibody titre compared to patients without side‐effects (P = 0·038). Haematological patients under treatment were at highest risk of serological non‐response. Low lymphocytes, NK cells and IgG levels were found to be associated with serological non‐response. Serological response in oncological patients was encouraging. The use of BNT162b2 is safe in haemato‐oncological patients.

Summary Patients with haemato‐oncological malignancies are one of the high‐risk groups for a severe course in case of COVID‐19 infections. Furthermore, vaccination results in significantly lower response rates in haematological malignancies and lower antibody levels in patients with solid cancer. We investigated efficacy and safety of a heterologous booster vaccination with Ad26.COV2.S DNA vector vaccine in haemato‐oncological patients without antibody response after double‐dose BNT162b2 messenger (m‐)RNA COVID‐19 vaccine. A total of 32 haemato‐oncological non‐responders to double‐dose BNT162b2 received a heterologous booster vaccination with Ad26.COV2.S. Blood samples were assessed directly before the vaccination (T0) and four weeks after (T1). Safety assessment was performed using a standardised questionnaire. The overall response rate was 31%, with a mean (SD) antibody titre of 693·79 (1 096·99) binding activity units (BAU)/ml. Patients with chronic lymphocytic leukaemia or lymphoma showed a significantly lower response rate (P = 0·048). Adverse events were reported in 29·6% of patients, of which 7·1% were graded as severe, including grade III and IV events following the Common Terminology Criteria of Adverse Events (CTCAE). The heterologous booster vaccination with Ad26.COV2.S led to a serological response in nine out of 29 patients without response after double‐dose BNT162b2. Furthermore, the vaccination was safe in our cohort, leading to mainly mild local and systemic reactions. Overall, this vaccination regimen should be further evaluated to increase the response rate in the highly vulnerable population of haemato‐oncological patients.

Cell surface syndecans and glypicans play important roles in the development and prognosis of colorectal cancer (CRC). Their soluble forms from proteoglycan shedding can be detected in blood and have been proposed as new prognostic biomarkers in several cancer entities. However, studies on circulating syndecan-1 (SDC1) and glypican-4 (GPC4) in CRC are limited. We, therefore, evaluated the impact of plasma SDC1 and GPC4 on the prognosis of metastatic (m)CRC patients. The present study included 93 patients with mCRC. The endpoints were progression-free survival (PFS) and overall survival (OS) at 12 months. SDC1 and GPC4 levels were measured in plasma using enzyme-linked immunosorbent assays. Plasma levels of SDC1 and GPC4 were significantly correlated. Significant correlations of these two markers were also found with carcinoembryonic antigen (CEA). Kaplan-Meier curve analyses indicated that PFS and OS probabilities significantly decreased with increasing levels of SDC1 and GPC4, respectively. Multivariable Cox regression analyses showed that both markers were significantly associated with PFS and OS independently from clinicopathological characteristics including CEA. Respective adjusted hazard ratios (HR) together with corresponding 95% confidence intervals for one standard deviation change of SDC1 were 1.32 [1.02-1.84] for PFS and 1.48 [1.01-2.15] for OS. Adjusted HRs [95% confidence intervals] of GPC4 were 1.42 [1.07-1.89] for PFS and 2.40 [1.51-3.81] for OS. Results from area under the receiver operating characteristic curve analyses suggest that GPC4 and SDC1 add additional prognostic values to CEA for OS. In conclusion, we showed significant associations of circulating SDC1 and GPC4 with poor survival of mCRC patients.