Development of Clinical-Stage Human Monoclonal Antibodies That Treat Advanced Ebola Virus Disease in Nonhuman Primates

Background

For most classes of drugs, rapid development of therapeutics to treat emerging infections is challenged by the timelines needed to identify compounds with the desired efficacy, safety, and pharmacokinetic profiles. Fully human monoclonal antibodies (mAbs) provide an attractive method to overcome many of these hurdles to rapidly produce therapeutics for emerging diseases.

Methods

In this study, we deployed a platform to generate, test, and develop fully human antibodies to Zaire ebolavirus. We obtained specific anti-Ebola virus (EBOV) antibodies by immunizing VelocImmune mice that use human immunoglobulin variable regions in their humoral responses.

Results

Of the antibody clones isolated, 3 were selected as best at neutralizing EBOV and triggering FcγRIIIa. Binding studies and negative-stain electron microscopy revealed that the 3 selected antibodies bind to non-overlapping epitopes, including a potentially new protective epitope not targeted by other antibody-based treatments. When combined, a single dose of a cocktail of the 3 antibodies protected nonhuman primates (NHPs) from EBOV disease even after disease symptoms were apparent.

Conclusions

This antibody cocktail provides complementary mechanisms of actions, incorporates novel specificities, and demonstrates high-level postexposure protection from lethal EBOV disease in NHPs. It is now undergoing testing in normal healthy volunteers in preparation for potential use in future Ebola epidemics.

Pneumocystosis pneumonia: A comparison study between HIV and non-HIV immunocompromised patients

Pneumocystis pneumonia (PCP) is caused by the fungus Pneumocystis jirovecii, and its incidence has been on the rise in immunosuppressed patients without HIV. We performed a cross sectional study in patients with PCP and assessed demographic, clinical presentation and outcome measures such as mechanical ventilation and mortality differences between HIV and non-HIV patients. The two groups were statistically significantly different, with the HIV group being younger (45.5 years vs 55.9 years, p-value 0.001) and mostly composed of male patients (69% vs 31%, p-value <0.001). Also, the HIV patients had higher percentage of respiratory complaints (90% vs 68%, p-value 0.02) and lactate dehydrogenase elevation (73% vs 40%, p-value 0.001). In contrast, non-HIV patients had worse outcomes with higher incidence of invasive mechanical ventilation (23% vs 46%, p-value 0.005) and in-hospital mortality (13% vs 37%, p-value 0.002). These results reflect the literature and should raise awareness to a potentially fatal medical situation of increasing incidence.

Safety and efficacy of intravenous immunoglobulin (Flebogamma® 10% DIF) in patients with immune thrombocytopenic purpura

Aim: To evaluate the safety and efficacy of 10% intravenous immunoglobulin (IVIG; Flebogamma® 10% DIF) in individuals with chronic immune thrombocytopenic purpura (ITP). Patients & methods: Patients aged 3–70 years, diagnosed with chronic ITP, received 1 g/kg IVIG over two consecutive days. Results: 64 evaluable patients (51 adults, 13 children) with chronic ITP received IVIG. The primary efficacy end point (increased platelet counts from ≤20 × 109/l to ≥50 × 109/l by day 8) was achieved by 81.3% of patients; mean time to response was 1.7 days (all responders). Adverse events, mostly mild or moderate, were reported in 59 patients (92.2%). Conclusion: Flebogamma® 10% DIF administered over two consecutive days was safe and effective in adults and children with chronic ITP.

54 Altrenogest supplementation during early pregnancy improves swine embryonic development

Progesterone (P4) is of paramount importance in the establishment and maintenance of pregnancy for mammals. Progesterone stimulates the endometrial secretion of several molecules involved in conceptus growth and development during the peri-implantation period. Indeed, several studies involving ruminants have reported that exogenous P4 supplementation is related to increased early embryo development, higher levels of interferon tau, and improved pregnancy rate. However, there is a lack of information about P4 supplementation during early pregnancy regarding swine embryonic development. Additionally, some of the few studies involving pigs have shown an impaired pregnancy rate when supplementation was performed before Day 6 of pregnancy. Thus, the objective of this study was to evaluate the effects of progesterone/progestin supplementation from Day 6 of pregnancy on total number of embryos (TE), pregnancy rate (PR), embryo development, and maternal serum 17β-oestradiol concentration (17β-E). A total of 31 crossbred, 2 to 6 parity sows were used. All sows were inseminated every 24h through the first oestrus following a 21-day lactation, and ovulation was detected by transrectal real-time ultrasound to determine Day 0 of pregnancy. On Day 6 of pregnancy, animals were randomly allocated to one of the following groups: CON (n=11), non-supplemented sows; RU (n=11), sows supplemented daily with 20mg of Altrenogest-Regumate® from Day 6 to 12 of pregnancy; and PG (n=9), sows supplemented with 2.15 mg/kg of long-acting P4 IM on Day 6 of pregnancy. Sows were treated with altrenogest p.o. as a top dressing over a small portion of feed. Blood samples were collected from 12 sows (4 per group) on Day 12 of pregnancy to measure the level of plasma 17β-E by radioimmunoassay. Sows were slaughtered on Day 28 of pregnancy. The uterus from each sow was collected and embryos were counted to determine TE. Embryos were individually separated from their placentas, weighed, and crown-to-rump length was determined. Data were analysed by the SAS program. All variables were analysed by PROC-MIXED t-test. Statistical difference was considered when P&lt;0.05. The PR did not differ among groups (91, 90, and 88%, for CON, RU, and PG, respectively; P&gt;0.05). No difference was observed among groups for TE and 17β-E level (P&gt;0.05). However, embryonic weight and crown-to-rump length differed among the 3 groups (P&lt;0.001). The RU-treated sows had heavier and bigger embryos when compared with the other groups. In contrast, PG-treated sows had the lowest averages for the same variables (weight: 1.39±0.01, 1.46±0.02, and 1.22±0.01; crown-to-rump: 21.07±0.08, 21.61±0.11, and 20.66±0.11; for CON, RU, and PG, respectively). In conclusion, altrenogest supplementation from Day 6 to 12 of pregnancy increases size and weight of porcine embryos, whereas 2.15mg kg−1 of long-acting P4 on Day 6 of pregnancy decreased these variables when compared with non-supplemented sows. Research was supported by FAPESP Grant 2017/00290-0.

Factor-XII Congenital Deficiency. A New Family Study

This report describes two people in a family with Hageman trait (homozygotes) (Factor XII = 0.06%). In addition eight family members were studied to evaluate the inheritance of this congenital deficiency. A study of the Kallikrein-Kininogen system induced by the fragments of Factor XII was also carried out.

It is concluded that the inheritance is as described by Veltkamp and that the Kallikrein release from the prekallikreinogen (Fletcher factor) “in vitro” is related to the amount of Factor XII procoagulant protein.

Immunoscintigraphy with 131I or 111In Labelled OC 125 F(ab')2 Fragments in Patients with Ovarian Carcinoma

To evaluate the clinical usefulness of immunoscintigraphy with OC 125 in ovarian carcinoma, we studied 25 patients suspected of having ovarian carcinoma or in follow-up after surgery. Fourteen patients were studied with 131I-OC 125 F(ab')2 and 11 with 111In-OC 125 F(ab')2. No differences were observed with the use of either radionuclide.

Global diagnostic indexes obtained were S = 100%, Sp = 44,5% and A = 81%. The low specificity obtained was remarkable: 5 false positive results in two uterine myomas, one abscess, one follicular cyst and one granulation tissue scar. On the other hand, all lesions of ovarian carcinoma were detected. Analysis of the evolution of tumor/background (T/B) uptake ratios from the first to the second day of exploration revealed a tendency for the ratio to diminish significantly (> 15%) in false positive cases with the exception of the abscess while this did not happen in true positive cases, with the exception of a regional recurrence. Analysis of T/B ratio variations could contribute towards elevating the test's specificity.

CA 549 and SP2 in postoperative breast cancer patients. Comparison with CA 15.3, CEA and TPA

The levels of CA 549 and SP2 were measured in 430 subjects: 100 healthy blood donors, 130 patients with benign diseases and 200 postoperative breast cancer patients. In the latter group, the serum levels of CA 15.3, CEA and TPA were also measured. The Kolmogorov-Smirnov, Mann Whitney and McNemar tests were used for statistical analysis. The upper normal limits were established on the basis of the values obtained in the healthy blood donors group, the benign diseases group and R.O.C. analysis of the breast cancer group. They were: CA 549 = 13 U/ml, SP2 = 14 U/ml, CA 15.3 = 35 U/ml, CEA = 5 ng/ml and TPA = 110 U/ml. The sensitivity, specificity and accuracy in the breast cancer group were, respectively: CA 549 = 78.1%, 97.1% and 88%; SP2 = 21.9%, 90.4% and 57.5%; CEA = 66.7%, 95.2% and 81.5%; CA 15.3 = 80.2%, 98.1% and 89.5%, and TPA = 73.9%, 78.8% and 76.5%. Statistical analysis showed significant differences only between CA 15.3, the marker which gave the best results, and SP2 (p<0.001). There were no significant differences with the association of two or three tumor markers.