Discovery of the Selective Protein Kinase C-θ Kinase Inhibitor, CC-90005

The PKC-θ isoform of protein kinase C is selectively expressed in T lymphocytes and plays an important role in the T cell antigen receptor (TCR)-triggered activation of mature T cells, T cell proliferation, and the subsequent release of cytokines such as interleukin-2 (IL-2). Herein, we report the synthesis and structure-activity relationship (SAR) of a novel series of PKC-θ inhibitors. Through a combination of structure-guided design and exploratory SAR, suitable replacements for the basic C4 amine of the original lead (3) were identified. Property-guided design enabled the identification of appropriately substituted C2 groups to afford potent analogs with metabolic stability and permeability to support in vivo testing. With exquisite general kinase selectivity, cellular inhibition of T cell activation as assessed by IL-2 expression, a favorable safety profile, and demonstrated in vivo efficacy in models of acute and chronic T cell activation with oral dosing, CC-90005 (57) was selected for clinical development.

FRI0084 SAFETY, PHARMACOKINETICS, PHARMACODYNAMICS, IMMUNOGENICITY, AND PRELIMINARY EFFICACY OF ROZIBAFUSP ALFA IN SUBJECTS WITH RHEUMATOID ARTHRITIS: INTERIM ANALYSIS OF A PHASE 1B RANDOMIZED, PLACEBO-CONTROLLED, MULTIPLE ASCENDING DOSE CLINICAL TRIAL

Background:

Autoimmune diseases, including systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA), are associated with autoantibody production and dysregulated T- and B-cell responses. Rozibafusp alfa (AMG 570) is a first-in-class bispecific antibody-peptide conjugate targeting T- and B-cell activity through inhibition of ICOSL and BAFF and is currently in phase 2 clinical development for the treatment of SLE.

Objectives:

This interim analysis of a phase 1b study (NCT03156023) reports the safety, pharmacokinetics (PK), pharmacodynamics (PD), immunogenicity, and preliminary efficacy of rozibafusp alfa in subjects with RA.

Methods:

Subjects (N~34; age 18–75 years) with active RA, defined as a disease activity score (DAS28-CRP) >2.6, were randomized 3:1 to receive rozibafusp alfa or placebo subcutaneously every 2 weeks for 10 weeks (6 doses), with 24 weeks of follow-up. Subjects were divided into 4 cohorts to study 4 ascending doses of rozibafusp alfa. All subjects were maintained on a stable dose of methotrexate. The primary endpoint was the subject incidence of treatment-emergent adverse events (TEAEs). Additional assessments included serum PK profiles, PD (eg, ICOSL receptor occupancy [RO], changes in peripheral blood B cells), incidence of anti-rozibafusp alfa antibodies, and Patient and Physician Global Assessments (PtGA and PhGA) of disease activity.

Results:

As of June 5, 2019, 34 subjects were enrolled and included in this interim analysis. Rozibafusp alfa was generally well tolerated. TEAEs occurred in 92.3% and 87.5% of subjects receiving rozibafusp alfa and placebo, respectively. Most of these events were of grade ≤2 severity. The most common TEAE was upper respiratory infection (23.1%) for subjects receiving rozibafusp alfa and nasopharyngitis (37.5%) for subjects receiving placebo. No treatment-related AEs were of grade ≥3 severity and occurred in >2 subjects. Rozibafusp alfa demonstrated a nonlinear PK profile with greater than a dose-proportional increase in concentration across evaluated doses. The terminal half-life of rozibafusp alfa ranged from 5 to 11 days, with longer half-lives at higher dose levels. ICOSL RO on circulating B-cells was dose-related and reversible; upon multiple dosing, >90% mean RO was observed in cohorts 3 and 4. Treatment with rozibafusp alfa reduced the percentage of naïve B-cells and increased the percentage of memory B-cells in all cohorts. As of March 22, 2019, 2 of 18 (11.1%) rozibafusp alfa-treated subjects developed anti-rozibafusp alfa antibodies with no correlation to safety or AEs. Preliminary analysis of disease-related activity showed a trend for greater numerical improvement from baseline in PtGA and PhGA with rozibafusp alfa vs. placebo in cohorts 3 and 4.

Conclusion:

This interim analysis is the first to report the safety and tolerability of multiple ascending doses of rozibafusp alfa in RA subjects, with preliminary efficacy findings observed in the highest dose cohorts. PK/PD analysis demonstrated nonlinear, target-mediated disposition consistent with cell surface target interaction and PD activity consistent with dual ICOSL/BAFF neutralization. These findings informed the design and dose selection of an ongoing phase 2, randomized, placebo-controlled study to assess the efficacy and safety of rozibafusp alfa in subjects with active SLE and inadequate responses to standard of care therapy.

Acknowledgments:

Amgen Inc. and AstraZeneca sponsored this phase 1b study

Disclosure of Interests:

Lubna Abuqayyas Shareholder of: Stockholder of Amgen Inc., Employee of: Employee of Amgen Inc., Laurence Cheng Shareholder of: Stockholder of Amgen Inc., Employee of: Former employee of Amgen Inc., Deepali Mitragotri Shareholder of: Stockholder of Amgen Inc., Employee of: Employee of Amgen Inc., Shawna Smith Shareholder of: Stockholder of Amgen Inc., Employee of: Employee of Amgen Inc., Marcia Teixeira dos Santos Shareholder of: Stockholder of Amgen Inc., Employee of: Employee of Amgen Inc., Yanchen Zhou Shareholder of: Stockholder of Amgen Inc., Employee of: Employee of Amgen Inc., Vishala Chindalore Grant/research support from: Nektar Therapeutics for conducted studies, Speakers bureau: > 5 years ago, Stanley Cohen Grant/research support from: Grant and research support from Amgen, AbbVie, Pfizer, Genentech, and Lilly, Consultant of: Consultant for Amgen, AbbVie, Pfizer, Genentech and Lilly, Alan Kivitz Shareholder of: AbbVie, Amgen, Gilead, GSK, Pfizer Inc, Sanofi, Consultant of: AbbVie, Boehringer Ingelheim,,Flexion, Genzyme, Gilead, Janssen, Novartis, Pfizer Inc, Regeneron, Sanofi, SUN Pharma Advanced Research, UCB, Paid instructor for: Celgene, Genzyme, Horizon, Merck, Novartis, Pfizer, Regeneron, Sanofi, Speakers bureau: AbbVie, Celgene, Flexion, Genzyme, Horizon, Merck, Novartis, Pfizer Inc, Regeneron, Sanofi, Maximilian Posch: None declared, Barbara Sullivan Shareholder of: Shareholder of Amgen Inc., Employee of: Former employee of Amgen Inc. Current employee of Ultragenyx, Jane Parnes Shareholder of: Stockholder of Amgen Inc., Employee of: Employee of Amgen Inc.

Evolutionary origins of taste buds: phylogenetic analysis of purinergic neurotransmission in epithelial chemosensors

Taste buds are gustatory endorgans which use an uncommon purinergic signalling system to transmit information to afferent gustatory nerve fibres. In mammals, ATP is a crucial neurotransmitter released by the taste cells to activate the afferent nerve fibres. Taste buds in mammals display a characteristic, highly specific ecto-ATPase (NTPDase2) activity, suggesting a role in inactivation of the neurotransmitter. The purpose of this study was to test whether the presence of markers of purinergic signalling characterize taste buds in anamniote vertebrates and to test whether similar purinergic systems are employed by other exteroceptive chemosensory systems. The species examined include several teleosts, elasmobranchs, lampreys and hagfish, the last of which lacks vertebrate-type taste buds. For comparison, Schreiner organs of hagfish and solitary chemosensory cells (SCCs) of teleosts, both of which are epidermal chemosensory end organs, were also examined because they might be evolutionarily related to taste buds. Ecto-ATPase activity was evident in elongate cells in all fish taste buds, including teleosts, elasmobranchs and lampreys. Neither SCCs nor Schreiner organs show specific ecto-ATPase activity, suggesting that purinergic signalling is not crucial in those systems as it is for taste buds. These findings suggest that the taste system did not originate from SCCs but arose independently in early vertebrates.

Intraoperative ice pack application for uvulopalatoplasty pain reduction: a randomized controlled trial

OBJECTIVES/HYPOTHESIS

Pain after uvulopalatoplasty continues to cause patients significant morbidity, especially from the tonsillectomy portion. The literature describes multiple techniques to reduce post-tonsillectomy pain, none being definitive. The purpose of this study was to evaluate the effect of intraoperative ice pack application on post-uvulopalatoplasty pain.

STUDY DESIGN

Single-blinded, randomized controlled trial.

METHODS

After inclusion and exclusion criteria were met, patients were enrolled and randomized, and subsequently underwent standard electrocautery uvulopalatoplasty. Packs were placed into the tonsillar fossae immediately following tonsil removal and into the palate after the palatoplasty. Patients then completed a questionnaire that evaluated their experience for 10 days following surgery. The primary outcome was pain rated on a visual analog scale. Return to work and return to normal diet were also assessed. T test and Mann-Whitney statistical analyses, as well as routine descriptive statistics, were conducted.

RESULTS

Eighteen subjects were recruited. Patients that received intraoperative cold packs experienced a statistically significant change in VAS average pain [3.4 ± 1.1 cm (p = 0.00001)] when compared with patients receiving room temperature packs. No difference in return to work (p = 0.16) and return to normal diet (p = 0.12) was identified.

CONCLUSIONS

Intraoperative ice pack administration results in significantly reduced pain following electrocautery uvulopalatoplasty.

CD31 mismatching affects marrow transplantation outcome

Graft-versus-host disease (GVHD) complicating allogeneic bone marrow transplantation (BMT) is often attributed to mismatched minor histocompatibility antigens (mHags), which are poorly defined in humans. CD31 is a candidate human mHag relevant to acute GVHD, but reports disagree about its level of significance, the role of HLA restriction, and the relative importance of different polymorphic codons within the molecule. We therefore examined in greater detail the impact of CD31-matching on BMT outcome in a prospective study from a single institution. Samples of recipient and donor DNA were collected pretransplantation for all patients receiving unmanipulated bone marrow from an HLA-identical sibling over a 45-month period at our institution. CD31 DNA typing of alleles at the 3 polymorphic codons 125 (L or V), 563 (N or S), and 670 (R or G) was performed for 118 patient-donor pairs plus 2 additional pairs who had codon 125 typing only. Donor-recipient CD31 nonidentity was tested for correlation with BMT clinical outcome measures of severe acute GVHD, chronic GVHD, relapse, and survival. Gene frequencies of approximately 0.5 for each allele at all 3 codons were comparable to previous reports. Because complete association was seen for 563N with 670G and for 563S with 670R, nonidentity for those codons was analyzed as a single genetic marker designated codon 563/670. Donor-recipient CD31 nonidentity was a significant risk factor for overall survival, both at codon 563/670 (hazard ratio [hr] = 2.58, P = .005) and at codon 125 (hr = 1.07, P = .036). Similar results held for disease-free survival. Nonidentity at codon 563/670 was also a significant risk factor (odds ratio [OR] = 11.15, P = .011) for severe (grades III, IV) versus no (grade 0) acute GVHD. Nonidentity at codon 125 posed less but still significant risk (OR = 9.30, P = .030). When the comparison group without severe acute GVHD was expanded to include grade I as well as grade 0 patients, the risk from CD31 nonidentity increased for both codon 563/670 (OR = 12.31, P = .010) and codon 125 (OR = 11.24, P = .011). CD31 nonidentity remained a significant independent risk factor for survival and for severe acute GVHD when tested in multivariate analysis with the covariates of adulthood, recipient-donor sex difference, ethnic group, disease, pretransplantation risk category, HLA-A2 type, B44-like types, and GVHD prophylactic regimen. CD31 nonidentity showed a trend but failed to achieve statistical significance as a risk factor for relapse and for chronic GVHD. In conclusion, donor-recipient CD31 nonidentity is a significant risk factor for survival and for severe acute GVHD in HLA-identical sibling BMT. The stronger associations with codon 563/670 suggest that polymorphism may be more important than the linked polymorphism at codon 125.

Transfection of the CD8 gene enhances T-cell recognition

Antibodies against CD8 or CD4 antigens can prevent T-cell functions induced by T-cell targets. As CD8 or CD4 antibodies can also initiate negative signals in T cells in the absence of appropriate targets it is not clear whether CD8 and CD4 molecules are directly involved in the interaction of T cells with their targets. In previous experiments we have introduced the T-cell receptor alpha- and beta-chain genes from a CD8-positive cytolytic T cell specific for the antigen fluorescein (FL) and the H-2D molecule of the major histocompatibility complex (MHC) into a CD8-negative recipient cell. The CD8-positive donor cell lysed both FL-conjugated fibroblasts and lymphoblasts, which express relatively high and low amounts of H-2D molecules, respectively. In contrast the CD8-negative transfectant lysed FL-conjugated fibroblasts only. Here we show that recognition of FL-conjugated lymphoblasts by the transfectant is enhanced by supertransfecting it with the CD8 gene.