Optimization of therapeutic antibodies for reduced self-association and non-specific binding via interpretable machine learning.

Antibody development, delivery, and efficacy are influenced by antibody-antigen affinity interactions, off-target interactions that reduce antibody bioavailability and pharmacokinetics, and repulsive self-interactions that increase the stability of concentrated antibody formulations and reduce their corresponding viscosity. Yet identifying antibody variants with optimal combinations of these three types of interactions is challenging. Here we show that interpretable machine-learning classifiers, leveraging antibody structural features descriptive of their variable regions and trained on experimental data for a panel of 80 clinical-stage monoclonal antibodies, can identify antibodies with optimal combinations of low off-target binding in a common physiological-solution condition and low self-association in a common antibody-formulation condition. For three clinical-stage antibodies with suboptimal combinations of off-target binding and self-association, the classifiers predicted variable-region mutations that optimized non-affinity interactions while maintaining high-affinity antibody-antigen interactions. Interpretable machine-learning models may facilitate the optimization of antibody candidates for therapeutic applications.

ImmTOR nanoparticles enhance AAV transgene expression after initial and repeat dosing in a mouse model of methylmalonic acidemia.

A major barrier to adeno-associated virus (AAV) gene therapy is the inability to re-dose patients due to formation of vector-induced neutralizing antibodies (Nabs). Tolerogenic nanoparticles encapsulating rapamycin (ImmTOR) provide long-term and specific suppression of adaptive immune responses, allowing for vector re-dosing. Moreover, co-administration of hepatotropic AAV vectors and ImmTOR leads to an increase of transgene expression even after the first dose. ImmTOR and AAV Anc80 encoding the methylmalonyl-coenzyme A (CoA) mutase (MMUT) combination was tested in a mouse model of methylmalonic acidemia, a disease caused by mutations in the MMUT gene. Repeated co-administration of Anc80 and ImmTOR was well tolerated and led to nearly complete inhibition of immunoglobulin (Ig)G antibodies to the Anc80 capsid. A more profound decrease of plasma levels of the key toxic metabolite, plasma methylmalonic acid (pMMA), and disease biomarker, fibroblast growth factor 21 (FGF21), was observed after treatment with the ImmTOR and Anc80-MMUT combination. In addition, there were higher numbers of viral genomes per cell (vg/cell) and increased transgene expression when ImmTOR was co-administered with Anc80-MMUT. These effects were dose-dependent, with the higher doses of ImmTOR providing higher vg/cell and mRNA levels, and an improved biomarker response. Combining of ImmTOR and AAV can not only block the IgG response against capsid, but it also appears to potentiate transduction and enhance therapeutic transgene expression in the mouse model.

Perspectives on the quality and utility of letters conforming to the AAIM guidelines.

Background Standardized letters of recommendation (SLOR) have become common features of the medical school to residency transition. Research has shown many advantages over the narrative letter of recommendation including improved letter-writing efficiency, ease of interpretation, and improved reliability as performance predictors. Currently, at least four specialties require fellowship SLORs. Internal medicine adopted its SLOR in 2017. Previous research showed fellowship program directors' satisfaction with the 2017 guidelines. Little is known about residency program directors' acceptance and adherence to the guidelines. Objectives The study sought to assess the adoption rate of each component, barriers to adoption, time commitment, and alignment with intended goals of the guidelines. Methods Anonymous survey links were posted to an internal medicine discussion forum prior to the guidelines in spring 2017 and twice following the guidelines in fall 2018 and winter 2019. Two-sample tests of proportions were used to compare respondent characteristics with known survey population data. Pre- and post-survey comparisons were assessed for statistical significance with Pearson chi-squared statistic. Results The response rate varied from 30% to 35% for each survey period. Medical knowledge, patient care, interpersonal and communication skills, professionalism, and scholarly activity were reported frequently (>96%) at baseline. Inclusion of residency program characteristics, systems-based practice, practice-based learning and improvement, and skills sought to master increased over the study period. Conclusions The new guidelines improved uniform reporting of all core competency data. Overall, the gains were modest, as many pre-survey respondents reported high rates of including components within the guidelines.

Enhancement of liver-directed transgene expression at initial and repeat doses of AAV vectors admixed with ImmTOR nanoparticles.

Systemic AAV (adeno-associated virus) gene therapy is a promising approach for the treatment of inborn errors of metabolism, but questions remain regarding its potency and durability. Tolerogenic ImmTOR nanoparticles encapsulating rapamycin have been shown to block the formation of neutralizing anti-capsid antibodies, thereby enabling vector re-administration. Here, we further demonstrate that ImmTOR admixed with AAV vectors also enhances hepatic transgene expression at the initial dose of AAV vector, independent of its effects on adaptive immunity. ImmTOR enhances AAV trafficking to the liver, resulting in increased hepatic vector copy numbers and transgene mRNA expression. Enhanced transgene expression occurs through a mechanism independent of the AAV receptor and cannot be replicated in vivo with free rapamycin or empty nanoparticles. The multipronged mechanism of ImmTOR action makes it an attractive candidate to enable more efficient transgene expression at first dose while simultaneously inhibiting adaptive responses against AAV to enable repeat dosing.

An Expanded Treatment Protocol of Panobinostat Plus Bortezomib and Dexamethasone in Patients With Previously Treated Myeloma.

BACKGROUND: Panobinostat was recently approved by the US Food and Drug Administration and European Commission in combination with bortezomib and dexamethasone for patients with multiple myeloma who have received ≥ 2 regimens, including bortezomib and an immunomodulatory drug. The PANEX (panobinostat expansion) treatment protocol provided access to panobinostat and gathered additional safety data before commercial availability. PATIENTS AND METHODS: In treatment phase 1, patients received panobinostat 20 mg 3 times per week plus bortezomib 1.3 mg/m2 twice weekly with dexamethasone 20 mg on the days of and after bortezomib treatment. Patients with no change or better in treatment phase 1 proceeded to treatment phase 2, when bortezomib was reduced to once weekly. Unlike in the phase III trial, PANORAMA-1 (panobinostat or placebo with bortezomib and dexamethasone in patients with relapsed multiple myeloma), bortezomib could be administered either subcutaneously or intravenously. RESULTS: Thirty-nine patients with a median number of previous treatments of 4 (range, 1-12) were enrolled; most received subcutaneous bortezomib (87%). The overall response rate (partial response or better) was 56%. Grade 3/4 adverse events included thrombocytopenia (47%), fatigue (31%), dehydration (26%), and diarrhea (18%). Among the patients who received subcutaneous bortezomib, relatively low rates of peripheral neuropathy (all grade, 15%) and notable grade 3/4 adverse events (thrombocytopenia, 47%; diarrhea, 12%) were observed. CONCLUSION: Overall, data from the PANEX trial support regulatory approval of panobinostat plus bortezomib and dexamethasone and suggest the potential tolerability benefits of subcutaneous bortezomib in this regimen.

SWOG S0910: a phase 2 trial of clofarabine/cytarabine/epratuzumab for relapsed/refractory acute lymphocytic leukaemia.

Precursor B-acute lymphoblastic leukaemias (pre-B ALLs) comprise the majority of ALLs and virtually all blasts express CD22 in the cytoplasm and on the cell surface. In the present study (Southwestern Oncology Group S0910), we evaluated the addition of epratuzumab, a humanized monoclonal antibody against CD22, to the combination of clofarabine and cytarabine in adults with relapsed/refractory pre-B ALL. The response rate [complete remission and complete remission with incomplete count recovery] was 52%, significantly higher than our previous trial with clofarabine/cytarabine alone, where the response rate was 17%. This result is encouraging and suggests a potential benefit to adding epratuzumab to chemotherapy for ALL; however, a randomized trial will be needed to answer this question.

A high LDH to AST ratio helps to differentiate pregnancy-associated thrombotic thrombocytopenic purpura (TTP) from HELLP syndrome.

OBJECTIVE: Differentiating between pre-eclampsia/HELLP syndrome and pregnancy-associated thrombotic thrombocytopenic purpura (TTP) is difficult but important in order to undertake timely and potentially life-saving plasma exchange (PEX) therapy for TTP recovery. We review our institutional experience with pregnancy-associated TTP and determine if the ratio of LDH to AST reliably distinguishes patients with TTP from those with HELLP syndrome. STUDY DESIGN: This is a retrospective case control study of all pregnant/puerperal patients with TTP from a single tertiary care center during 1986-2006. Laboratory findings in patients with TTP were compared to patients who met all criteria for class 1 or 2 HELLP syndrome within the first 24 hours of hospital admission during 2000-2007. RESULTS: Thirteen pregnant (n = 10) or puerperal (n = 3) patients with TTP were identified; 11 cases were primary, 2 were recurrent. TTP laboratory findings included LDH to AST ratios of 77 ± 42.17; Patients with HELLP syndrome (N = 83) had significantly lower LDH to AST ratios of 20.04 ± 2.13. Based on an ROC analysis, an LDH/AST ratio ≥ 22.12 discriminates well between TTP and antenatal HELLP subjects (AUC = 0.99). CONCLUSION: A high LDH to AST ratio >22.12 suggests that TTP is a more likely diagnosis than HELLP syndrome in the third trimester pregnant patient, presenting with findings that could be compatible with either diagnosis. In these circumstances, it is advisable to obtain hematology consultation and to consider PEX implementation.

Interaction of dietary resveratrol with animal-associated bacteria.

Resveratrol (3,5,4'-trihydroxy-trans-stilbene), an antifungal phytoalexin produced by grapes, peanuts, and Japanese knotweeds, is thought to be a beneficial dietary phytochemical in red wine and grape juice. Information on its antibacterial properties and biotransformation, however, is limited. We surveyed the interactions of resveratrol with 43 strains of bacterial species that are often animal- or human-associated. Resveratrol at 50 mg L(-1) reduced the growth rates of most of the bacteria tested, but did not totally prevent growth even at much higher levels. Eleven of the 43 bacteria were capable of transforming at least 20% of the resveratrol. Three major metabolites were identified as resveratroloside, piceid, and dihydroresveratrol, and three other metabolites were partially characterized.

Bortezomib successfully reduces monoclonal serum free light chain levels in a patient with recurrent myeloma and cast nephropathy in the renal transplant.

Bortezomib can be used to successfully treat acute kidney injury in the renal transplant allograft due to light chain cast nephropathy from recurrent multiple myeloma.

Thrombocytosis during antifungal therapy of candidemia.

BACKGROUND: Secondary, "reactive," thrombocytosis has been attributed to bacterial infection and treatment with multiple pharmaceuticals and may be associated with an increase in the incidence of gastrointestinal tract bleeding and thrombotic events (eg, stroke). OBJECTIVE: To characterize the dynamics of thrombocytosis in patients with candidemia receiving antifungal therapy. METHODS: We initiated a retrospective observational description of patients with candidemia who were treated with antifungal agents. A total of 108 patients diagnosed with candidemia between August 1995 and September 2003 at our teaching hospital were enrolled. Three groups (candidemia with antifungal therapy, candidemia without antifungal therapy, antifungal therapy without candidemia) of patients >18 years of age were evaluated for the presence of thrombocytosis. Platelet administration, pharmacologic or pathologic contributors to thrombocytosis, and other pertinent details related to an elevation of platelet counts were scrutinized. RESULTS: Reactive thrombocytosis was observed in approximately 10% of treated patients with candidemia. Within the subgroup developing reactive thrombocytosis, life-threatening thrombotic complications were uncommon. Mean baseline platelet counts were 393 x 10(3)/mm3, with a mean peak (695 x 10(3)/mm3) occurring an average of 13 days after initiation of therapy. All patients had resolution within 7 days after therapy. The maximum peak (1056 x 10(3)/mm3) was observed in a patient after 14 days of antifungal therapy. The onset of thrombocytosis in this patient was 4 days and lasted 4 days after therapy. CONCLUSIONS: Reactive thrombocytosis occurs during treatment of candidemia. The causative agent (drug vs disease), the risk associated with this reaction, and evaluation of treatment need to be elucidated by a larger epidemiologic study or controlled, prospective clinical trial.

Unusual skin lesions in chronic myelomonocytic leukemia.

Chronic myelomonocytic leukemia (CMML) is a relatively rare, heterogeneous syndrome classified as a myelodysplastic syndrome according to the French-American-British classification system. The patient's presenting symptom was a pigmented skin nodule that, although common for cases of acute monoblastic leukemia, is peculiar for CMML. This case should increase awareness of the inclusion of CMML in the differential diagnosis of a discolored nodule and highlight the clinicopathologic considerations and therapeutic challenges consistent with the diagnosis of CMML.