Outcome of immune checkpoint inhibitors in metastatic renal cell carcinoma across different treatment lines.

BACKGROUND: Immune checkpoint inhibitors (ICIs) have led to a paradigm change in the management of metastatic renal cell carcinoma (mRCC). Prospective trials have focused on ICI treatment in the first or second line. The aim of this analysis is to evaluate the benefit of ICI across different treatment lines. PATIENTS AND METHODS: This is a single-center retrospective study that included mRCC patients who received ICIs in various treatment lines. Objective response rates (ORR), progression-free survival (PFS) and overall survival (OS) were evaluated. RESULTS: Ninety-four patients were eligible for full evaluation. Patients were classified as International mRCC Database Consortium (IMDC) risk group categorization as good, intermediate and poor risk in 26.8%, 61.6% and 14.8% of cases, respectively. They were treated with ICI monotherapy, dual ICI therapy and ICI + tyrosine kinase inhibitor in 59%, 20% and 21% of cases, respectively. ORR, median PFS and OS for the entire cohort was 39.4%, 9.67 months [95% confidence interval (CI) 6.9-12.4 months] and 23.6 months (95% CI 13.3-33.9 months), respectively. The ORR by treatment line was 33% in first, 40.4% in the second, 35% in the third and 43.5% in the fourth line and beyond. Median PFS by treatment line was 8.6, 10.3, 7.9 and 7.23 months, respectively. The median OS was not reached in first-line treatment and was 26.2, 18.1 and 20.7 months in the second, third and fourth line and beyond, respectively. CONCLUSIONS: ICIs or ICI combinations are active in all treatment lines and should also be offered in heavily pretreated patients. Patient selection based on tumor and patient factors allows for maximal benefit from ICI-based therapies.

Inhibition of tissue kallikrein by protein C inhibitor. Evidence for identity of protein C inhibitor with the kallikrein binding protein.

We studied the inhibition of tissue kallikrein by protein C inhibitor (PCI), a relatively unspecific heparin-dependent serine protease inhibitor present in plasma and urine. PCI inhibited the amidolytic activity (cleavage of H-D-valyl-L-leucyl-arginine-p-nitroaniline) of urinary kallikrein with an apparent second order rate constant of 2.3 x 10(4) M-1 s-1 and formed stable complexes (85 kDa) with urinary kallikrein as judged from silver-stained sodium dodecyl sulfate-polyacrylamide gels. Complex formation was time-dependent and was paralleled by a decrease in the intensity of the main PCI protein band (Mr = 57,000) and an increase in the intensity of the lower Mr (54,000) PCI form (cleaved inhibitor). Heparin interfered with the inhibition of tissue kallikrein by PCI and with the formation of tissue kallikrein-PCI complexes in a dose-dependent fashion and completely abolished PCI-tissue kallikrein interaction at 300 micrograms/ml. This is in contrast to findings on the interaction of PCI with all other target proteases studied so far (i.e. stimulation of inhibition by heparin) but is similar to the reaction pattern of 125I-labeled tissue kallikrein with so called kallikrein binding protein described in serum and other systems. To study a possible relationship between PCI and this kallikrein binding protein we incubated 125I-labeled urinary kallikrein in serum and in PCI-immunodepleted serum in the absence and presence of heparin and analyzed complex formation using sodium dodecyl sulfate-polyacrylamide gel electrophoresis. In normal serum, formed complexes co-migrated with complexes of purified PCI and 125I-kallikrein and were less intense in the presence of heparin. No complex formation at all was seen in PCI-depleted serum. Our data indicate that PCI may be a physiologically important endogenous inhibitor of tissue kallikrein and provide evidence that PCI may be identical to the previously described kallikrein binding protein.

Possible identity of kallikrein binding protein with protein C inhibitor.

Protein C inhibitor (PCI) inhibits tissue kallikrein by forming stable 1:1 complexes (k1 = 2.3 x 10(4)M-1s-1). Heparin inhibits the tissue kallikrein/PCI-interaction and complex formation of 125I-tissue kallikrein in serum. 125I-tissue kallikrein complexes formed in plasma can be immunoprecipitated with monoclonal anti-PCI IgG suggesting that PCI might be identical to the kallikrein binding protein described previously (J. Chao et al. 1986, Biochem. J. 239, 325-331).

Plasminogen activator inhibitor-1 levels in patients with chronic angina pectoris with or without angiographic evidence of coronary sclerosis.

Increased plasma levels of plasminogen activator inhibitor-1 (PAI-1) have been shown to exist in 40 to 60% of patients with stable coronary artery disease and have been suggested to be responsible for the development of coronary thrombotic complications. However, it is also discussed whether PAI-1 elevation might mainly be due to variables like increased age or to reactive mechanisms caused e.g. by the chest pain itself. To exclude age dependent or pain related influences, age-matched patients with stable angina pectoris (NHYA II) and angiographically proven coronary artery disease (CAD, n = 16) or without evidence for coronary sclerosis (variant angina, n = 10; angina-like syndrome with normal coronary angiogram, n = 5; non-CAD, n = 15) have been investigated for their plasma PAI-1 activity and t-PA antigen levels. The mean PAI activity in CAD patients (17.5 U/ml) was significantly higher than in non-CAD patients (9.6 U/ml) (p less than 0.0001). In the CAD patients no significant variation in plasma PAI-1 values could be demonstrated when related to the extent of the disease or to a history of previous myocardial infarction. t-PA antigen was also elevated in CAD patients as compared to the non-CAD group (p less than 0.02). The results suggest therefore a strong correlation between coronary artery disease itself and elevated levels of components of the plasma fibrinolytic system.

Heparin induced increase of t-PA antigen plasma levels in patients with unstable angina: no evidence for clinical benefit of heparinization during the initial phase of treatment.

Patients with unstable coronary artery disease were randomly treated either with a combination therapy consisting of nitrates and calcium-channel blockers without or with addition of clinical grade heparin administered subcutaneously; in order to evaluate the effect of heparin treatment on the fibrinolytic system, tissue plasminogen activator (t-PA) and plasminogen activator inhibitor-1 (PAI-1) plasma levels were related to the clinical course of the disease. In heparinized patients thrombin time was prolonged more than 3-fold the normal range indicating effective heparin treatment. Heparinization led to a significant increase in t-PA antigen plasma levels (p less than 0.0001) within approximately four hours while PAI-1 activities remained unaltered. However, the measurable increase of the anticoagulant and pro-fibrinolytic activities of heparin did not result in a short-term benefit for the heparinized patients because the number of further ischemic attacks per patient during the observation period of three days was not different between the two study groups.

Circadian fluctuations of plasminogen activator inhibitor and tissue plasminogen activator levels in plasma of patients with unstable coronary artery disease and acute myocardial infarction.

A decrease in the fibrinolytic potential, mainly due to an elevation of plasminogen activator inhibitor (PAI), has been described in patients with stable coronary artery disease and a previous myocardial infarction. We investigated plasma levels of PAI and tissue plasminogen activator (t-PA) and their possible circadian variations in patients with unstable coronary artery disease (CAD). Sixty-three patients were studied for at least 2 consecutive days during their stay at the coronary care unit (CCU). Diurnal plasma fluctuations in PAI and t-PA and onset of further myocardial ischemic episodes were monitored. As controls we used 22 age-matched patients submitted to the clinic because of non cardiac chest pain or valvular disease who revealed no evidence of CAD. PAI levels were significantly elevated in patients with unstable CAD (p less than 0.0001) but were not influenced by the extent of underlying CAD, history of previous myocardial infarction, known risk factors for CAD, or by extent of myocardial damage. The circadian variation of PAI levels with peak values between midnight and 6 A.M. found in controls was still present in patients but at a higher level. Preservation of circadian pattern in PAI plasma levels despite myocardial ischemic attacks indicates that elevation of PAI is rather not caused by a reactive phenomenon. On the other hand, elevated PAI levels and episodes of severe myocardial ischemia exhibiting a median time of onset at 10 A.M. seem to be closely related.

Effect of the cyanogen-bromide-2 fragment of fibrinogen on plasminogen activation by single-chain urokinase-type plasminogen activator.

Activation of Glu-plasminogen by single-chain urokinase-type plasminogen activator (sc-uPA), isolated from human urine, was studied in a purified system in the absence and presence of the cyanogen bromide fibrinogen fragment, FCB 2, and compared to plasminogen activation by two-chain high-Mr urokinase. Plasminogen activation by sc-uPA was significantly increased by the FCB-2 fibrinogen fragment, an effect brought about by decrease of apparent Km and increase of apparent kcat. During the course of plasminogen activation by scu-PA, two-chain urokinase was formed from 125I-sc-uPA to a significant degree only when a concentration of 30 nM plasmin was reached in the incubation mixture; this was only the case in the system stimulated by FCB-2 fibrinogen fragment and only after 30 min. Formation of two-chain urokinase was not, however, related to the increase in the rate of plasmin formation induced by the FCB-2 fibrinogen fragment.