A phase 1 first-in-human study of GS-0189, an anti-signal regulatory protein alpha (SIRPα) monoclonal antibody, in patients with relapsed/refractory (R/R) non-Hodgkin lymphoma (NHL).

Signal regulatory protein alpha (SIRPα) is the receptor for cluster of differentiation (CD)47, a potent "don't eat me" signal for macrophages. Disruption of CD47-SIRPα signaling in the presence of prophagocytic signals can lead to enhanced phagocytosis of tumor cells, resulting in a direct antitumor effect; agents targeting this pathway have shown efficacy in non-Hodgkin lymphoma (NHL) and other tumor types. GS-0189 is a novel anti-SIRPα humanized monoclonal antibody. Here we report: (1) clinical safety, preliminary activity, and pharmacokinetics of GS-0189 as monotherapy and in combination with rituximab from a phase 1 clinical trial in patients with relapsed/refractory NHL (NCT04502706, SRP001); (2) in vitro characterization of GS-0189 binding to SIRPα; and (3) in vitro phagocytic activity. Clinically, GS-0189 was well tolerated in patients with relapsed/refractory NHL with evidence of clinical activity in combination with rituximab. Receptor occupancy (RO) of GS-0189 was highly variable in NHL patients; binding affinity studies showed significantly higher affinity for SIRPα variant 1 than variant 2, consistent with RO in patient and healthy donor samples. In vitro phagocytosis induced by GS-0189 was also SIRPα variant-dependent. Although clinical development of GS-0189 was discontinued, the CD47-SIRPα signaling pathway remains a promising therapeutic target and should continue to be explored.

Phase 1 first-in-human study of dalutrafusp alfa, an anti-CD73-TGF-ß-trap bifunctional antibody, in patients with advanced solid tumors.

BACKGROUND: Cluster of differentiation (CD)73-adenosine and transforming growth factor (TGF)-ß pathways are involved in abrogated antitumor immune responses and can lead to protumor conditions. This Phase 1 study (NCT03954704) evaluated the safety, pharmacokinetics, pharmacodynamics, and efficacy of dalutrafusp alfa (also known as GS-1423 and AGEN1423), a bifunctional, humanized, aglycosylated immunoglobulin G1 kappa antibody that selectively inhibits CD73-adenosine production and neutralizes active TGF-ß signaling in patients with advanced solid tumors. METHODS: Dose escalation started with an accelerated titration followed by a 3+3 design. Patients received dalutrafusp alfa (0.3, 1, 3, 10, 20, 30, or 45 mg/kg) intravenously every 2 weeks (Q2W) up to 1 year or until progressive disease (PD) or unacceptable toxicity. RESULTS: In total, 21/22 patients received at least one dose of dalutrafusp alfa. The median number of dalutrafusp alfa doses administered was 3 (range 1-14). All patients had at least one adverse event (AE), most commonly fatigue (47.6%), nausea (33.3%), diarrhea (28.6%), and vomiting (28.6%). Nine (42.9%) patients had a Grade 3 or 4 AE; two had Grade 5 AEs of pulmonary embolism and PD, both unrelated to dalutrafusp alfa. Target-mediated drug disposition appears to be saturated at dalutrafusp alfa doses above 20 mg/kg. Complete CD73 target occupancy on B cells and CD8+ T cells was observed, and TGF-ß 1/2/3 levels were undetectable at dalutrafusp alfa doses of 20 mg/kg and higher. Free soluble (s)CD73 levels and sCD73 activity increased with dalutrafusp alfa treatment. Seventeen patients reached the first response assessment, with complete response, partial response, stable disease, and PD in 0, 1 (4.8%), 7 (33.3%), and 9 (42.9%) patients, respectively. CONCLUSIONS: Dalutrafusp alfa doses up to 45 mg/kg Q2W were well tolerated in patients with advanced solid tumors. Additional evaluation of dalutrafusp alfa could further elucidate the clinical utility of targeting CD73-adenosine and TGF-ß pathways in oncology.

Human Immunodeficiency Virus (HIV)- and Non-HIV-Associated Immunosuppression and Risk of Cervical Neoplasia.

OBJECTIVE: To estimate the risk of cervical intraepithelial neoplasia grade 2, 2-3, 3, adenocarcinoma in situ, or cancer (CIN 2 or worse) among women with human immunodeficiency virus (HIV)- and non-HIV-associated immunosuppression. METHODS: We performed a case-control study of 20,146 women with incident CIN 2 or worse and 5:1 age-matched, incidence-density selected women in a control group (n=100,144) enrolled in an integrated health care system from 1996 to 2014. Adjusted rate ratios (RRs) from conditional logistic regression were obtained for HIV status (stratified by CD4 T-cells), solid organ transplant history, and immunosuppressive medication use. RESULTS: Risk of CIN 2 or worse was increased among women with HIV (n=36 women in the case group and 79 women in the control group; adjusted RR 2.0, 95% CI 1.3-3.0) compared with those without HIV and in solid organ transplant recipients (n=51 women in the case group and 68 women in the control group; RR 3.3, 95% CI 2.3-4.8) compared with women without a prior transplant. The highest risks were among women with HIV and less than 200 CD4 T-cells/microliter (n=9 women in the case group and eight women in the control group; RR 5.6, 95% CI 2.1-14.7) compared with those without HIV and in solid organ transplant recipients prescribed three or greater immunosuppressive medication classes (n=32 women in the case group and 33 women in the control group; RR 4.1, 95% CI 2.5-6.8) compared with women without a prior transplant and zero medication classes. No increased risks were observed for women with HIV and 500 or greater CD4 T-cells/microliter (n=9 women in the case group and 43 women in the control group; RR 0.8, 95% CI 0.4-1.7) compared with those without HIV or women without prior solid organ transplantation prescribed two or fewer immunosuppressive medication classes (n=1,262 women in the case group and 6,100 women in the control group; RR 0.95, 95% CI 0.89-1.01) compared with women without and a prior transplant and zero medication classes. CONCLUSION: Risk of CIN 2 or worse is increased in women with a prior solid organ transplant or who have HIV and CD4 cells/microliter less than 500 but not in women with HIV and higher CD4 levels or in women without a prior solid organ transplant but who are prescribed only one or two immunosuppressive medication classes.

Discrepancies in identification of major bleeding events in patients taking warfarin.

STUDY OBJECTIVE: To assess the level of agreement between one subjective definition of major bleeding (criteria A) and two objective definitions: the International Society on Thrombosis and Haemostasis ([ISTH] criteria B) and the Italian Study of Complications of Anticoagulant Therapy ([ISCOAT] criteria C). DESIGN: Retrospective cohort study. SETTING: Four anticoagulation clinics at a university-affiliated medical center. PATIENTS: One hundred twenty patients aged 21-96 years who were taking long-term warfarin therapy and experienced a nonminor bleeding event between July 1, 2001, and June 30, 2006. MEASUREMENTS AND MAIN RESULTS: Bleeding events were evaluated using three definitions of major bleeding: criteria A-event was fatal or required hospitalization; criteria B-event was fatal, was symptomatic in a critical area or organ, caused a decrease in hemoglobin level of 2 g/dl or more, and/or led to transfusion of 2 or more units of whole blood or red blood cells; and criteria C-event met criteria B definition (but less inclusively identifies critical areas or organs) and/or necessitated surgical or angiographic intervention. One hundred thirty-eight bleeding events in the 120 patients met at least one of the definitions of major bleeding and thus were included in the analysis. Level of agreement among the definitions was determined by the kappa statistic. The level of agreement between criteria B and C was excellent; no discrepancies were found; however, the level of agreement between criteria A and criteria B or C was poor, with a kappa statistic value of -0.134 (95% confidence interval -0.196 to -0.071). Use of criteria A resulted in underreporting of 31 major bleeding events by excluding events that were managed on an outpatient basis. CONCLUSION: The discrepant event rates determined by using three different definitions of major bleeding underscore the need for implementation of a standardized objective definition. Use of a standardized definition in clinical trials to accurately predict and compare patient outcomes and in clinical practice as a marker for patient safety will increase quality of care and decrease total costs of care in patients treated with warfarin. We suggest implementation of the ISTH criteria in clinical practice as a method to standardize the reporting of major bleeding events.