Intravesical therapy with the trifunctional anti-EpCAM/CD3 bsAb Catumaxomab is well tolerated and shows encouraging preliminary efficacy in patients with high-risk NMIBC (CATUNIBLA phase I trial)

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Background: Tx of high-risk NMIBC is challenging due to a high risk of recurrence. Novel therapeutic options are highly anticipated to avoid cystectomy and disease progression. Malignant transitional cells express EpCAM. The trifunctional anti-EpCAM/CD3 bsAb Catumaxomab (CAT) mediates cell killing against human BC. This dose escalating Phase I trial (NCT04819399) investigates the safety of intravesical CAT in high-risk NMIBC. Methods: Following first TUR-B, pts with newly diagnosed high-risk NMIBC were enrolled and received 6 x weekly intravesical CAT instillations, each of 2h duration) at a dose of 50 or 70μg. Subsequently, 2nd TUR-B and adjuvant instillation therapy (tx) was performed as SoC. Here, we report the safety and preliminary efficacy of dose cohorts 1 and 2. Results: 7 Pts are included, 5 with pTa, 2 with pT1 disease. There were 5 concomitant pTis. 6/7 pts received the planned 6 x weekly CAT instillations. 1 pt discontinued after 1 instillation due to recurrent UTI. No DLTs occurred. 28 AEs were observed in 6/7 pts, all of gr 1-2 except two unrelated gr 3 AEs . 2/7 pts had an unrelated SAE each (1 hydronephrosis, 1 recurrent fever after BCG). For 6/7 pts cytokines were below LLQ. In one pt of cohort 2 low amounts of IL-6 and IL-8 were detectable. Weak HAMA responses in 5/6 pts transiently occurred at days 29 and 43. CAT instillations led to transient increases of urinary leukocytes. During and after CAT treatment, there was a strong trend towards reduction of EpCAM+ cells in urine. At 2nd TUR-B tumour persistency was observed in two patients only. Remarkably, 3/5 pTis were no longer detected at 2nd TUR-B. So far, 5/7 pts received adjuvant BCG, 2 pts declined. 7/7 pts achieved CR as best response. While 2/3 pts in the 50 μg cohort had a recurrence, no recurrence was observed in the 70 μg cohort. Conclusions: Intravesical instillations with the trifunctional, anti-EpCAM/anti-CD3 bsAb Catumaxomab are well tolerated in pts with high risk NMIBC. CAT does not enter systemic circulation and elicits only low and transient immunogenicity. The MTD is not reached and dose escalation is still ongoing with cohort 3 (100 μg)(updated results will be presented at meeting). The reduction in EpCAM+ urine cells indicates potential activity of this novel immunotherapy and the high CR rate of Tis at the end of CAT therapy is promising. Clinical trial information: NCT04819399. [Table: see text]

Ribonuclease (RNase) Prolongs Survival of Grafts in Experimental Heart Transplantation

BACKGROUND

Cell damage, tissue and vascular injury are associated with the exposure and release of intracellular components such as RNA, which promote inflammatory reactions and thrombosis. Based on the counteracting anti-inflammatory and cardioprotective functions of ribonuclease A (RNase A) in this context, its role in an experimental model of heart transplantation in rats was studied.

METHODS AND RESULTS

Inbred BN/OrlRj rat cardiac allografts were heterotopically transplanted into inbred LEW/OrlRj rats. Recipients were intravenously treated every other day with saline or bovine pancreatic RNase A (50 μg/kg). Toxic side effects were not found (macroscopically and histologically). Heart tissue flow cytometry and quantitative morphological analyses of explanted hearts at postoperative day 1 or postoperative day 4 showed reduced leukocyte infiltration, edema, and thrombus formation in RNase A-treated rats. In allogeneic mixed lymphocyte reactions, RNase A decreased the proliferation of effector T cells. RNase A treatment of rats resulted in prolonged median graft survival up to 10.5 days (interquartile range 1.8) compared to 6.5 days (interquartile range 1.0) in saline treatment (P=0.001). Treatment of rats with a new generated (recombinant) human pancreatic RNase 1 prolonged median graft survival similarly, unlike treatment with (recombinant) inactive human RNase 1 (each 50 μg/kg IV every other day, 11.0 days, interquartile range 0.3, versus 8.0 days, interquartile range 0.5, P=0.007).

CONCLUSIONS

Upon heart transplantation, RNase administration appears to present a promising and safe drug to counteract ischemia/reperfusion injury and graft rejection. Furthermore, RNase treatment may be considered in situations of critical reperfusion after percutaneous coronary interventions or in cardiac surgery using the heart-lung machine.

Extracellular RNA promotes leukocyte recruitment in the vascular system by mobilising proinflammatory cytokines

Extracellular RNA (eRNA), released from cells under conditions of injury or vascular disease, acts as potent prothrombotic factor and promotes vascular hyperpermeability related to oedema formation in vivo. In this study, we aimed to investigate the mechanism by which eRNA triggers inflammatory processes, particularly associated with different steps of leukocyte recruitment. Using intravital microscopy of murine cremaster muscle venules, eRNA (but not DNA) significantly induced leukocyte adhesion and transmigration in vivo, which was comparable in its effects to the function of tumour-necrosis-factor-α (TNF-α). In vitro, eRNA promoted adhesion and transmigration of monocytic cells on and across endothelial cell monolayers. eRNA-induced monocyte adhesion in vitro was mediated by activation of the vascular endothelial growth factor (VEGF)/VEGF-receptor-2 system and was abolished by neutralising antibodies against intercellular adhesion molecule-1 or the β2-integrin Mac-1. Additionally, eRNA induced the release of TNF-α from monocytic cells in a time- and concentration-dependent manner, which involved activation of TNF-α-converting enzyme (TACE) as well as the nuclear factor κB signalling machinery. In vivo, inhibiton of TACE significantly reduced eRNA-induced leukocyte adhesion. Our findings present evidence that eRNA in connection with tissue/vascular damage provokes a potent inflammatory response by inducing leukocyte recruitment and by mobilising proinflammatory cytokines from monocytes.