Garetosmab in fibrodysplasia ossificans progressiva: a randomized, double-blind, placebo-controlled phase 2 trial

Fibrodysplasia ossificans progressiva (FOP) is a rare disease characterized by heterotopic ossification (HO) in connective tissues and painful flare-ups. In the phase 2 LUMINA-1 trial, adult patients with FOP were randomized to garetosmab, an activin A-blocking antibody (n = 20) or placebo (n = 24) in period 1 (28 weeks), followed by an open-label period 2 (28 weeks; n = 43). The primary end points were safety and for period 1, the activity and size of HO lesions. All patients experienced at least one treatment-emergent adverse event during period 1, notably epistaxis, madarosis and skin abscesses. Five deaths (5 of 44; 11.4%) occurred in the open-label period and, while considered unlikely to be related, causality cannot be ruled out. The primary efficacy end point in period 1 (total lesion activity by PET-CT) was not met (P = 0.0741). As the development of new HO lesions was suppressed in period 1, the primary efficacy end point in period 2 was prospectively changed to the number of new HO lesions versus period 1. No placebo patients crossing over to garetosmab developed new HO lesions (0% in period 2 versus 40.9% in period 1; P = 0.0027). Further investigation of garetosmab in FOP is ongoing. ClinicalTrials.gov identifier NCT03188666 .

Genomic diagnostics within a medically underserved population: efficacy and implications

PurposeWe integrated whole-exome sequencing (WES) and chromosomal microarray analysis (CMA) into a clinical workflow to serve an endogamous, uninsured, agrarian community.MethodsSeventy-nine probands (newborn to 49.8 years) who presented between 1998 and 2015 remained undiagnosed after biochemical and molecular investigations. We generated WES data for probands and family members and vetted variants through rephenotyping, segregation analyses, and population studies.ResultsThe most common presentation was neurological disease (64%). Seven (9%) probands were diagnosed by CMA. Family WES data were informative for 37 (51%) of the 72 remaining individuals, yielding a specific genetic diagnosis (n = 32) or revealing a novel molecular etiology (n = 5). For five (7%) additional subjects, negative WES decreased the likelihood of genetic disease. Compared to trio analysis, "family" WES (average seven exomes per proband) reduced filtered candidate variants from 22 ± 6 to 5 ± 3 per proband. Nineteen (51%) alleles were de novo and 17 (46%) inherited; the latter added to a population-based diagnostic panel. We found actionable secondary variants in 21 (4.2%) of 502 subjects, all of whom opted to be informed.ConclusionCMA and family-based WES streamline and economize diagnosis of rare genetic disorders, accelerate novel gene discovery, and create new opportunities for community-based screening and prevention in underserved populations.

Genetic and Pharmacologic Inactivation of ANGPTL3 and Cardiovascular Disease

BACKGROUND

Loss-of-function variants in the angiopoietin-like 3 gene (ANGPTL3) have been associated with decreased plasma levels of triglycerides, low-density lipoprotein (LDL) cholesterol, and high-density lipoprotein (HDL) cholesterol. It is not known whether such variants or therapeutic antagonism of ANGPTL3 are associated with a reduced risk of atherosclerotic cardiovascular disease.

METHODS

We sequenced the exons of ANGPTL3 in 58,335 participants in the DiscovEHR human genetics study. We performed tests of association for loss-of-function variants in ANGPTL3 with lipid levels and with coronary artery disease in 13,102 case patients and 40,430 controls from the DiscovEHR study, with follow-up studies involving 23,317 case patients and 107,166 controls from four population studies. We also tested the effects of a human monoclonal antibody, evinacumab, against Angptl3 in dyslipidemic mice and against ANGPTL3 in healthy human volunteers with elevated levels of triglycerides or LDL cholesterol.

RESULTS

In the DiscovEHR study, participants with heterozygous loss-of-function variants in ANGPTL3 had significantly lower serum levels of triglycerides, HDL cholesterol, and LDL cholesterol than participants without these variants. Loss-of-function variants were found in 0.33% of case patients with coronary artery disease and in 0.45% of controls (adjusted odds ratio, 0.59; 95% confidence interval, 0.41 to 0.85; P=0.004). These results were confirmed in the follow-up studies. In dyslipidemic mice, inhibition of Angptl3 with evinacumab resulted in a greater decrease in atherosclerotic lesion area and necrotic content than a control antibody. In humans, evinacumab caused a dose-dependent placebo-adjusted reduction in fasting triglyceride levels of up to 76% and LDL cholesterol levels of up to 23%.

CONCLUSIONS

Genetic and therapeutic antagonism of ANGPTL3 in humans and of Angptl3 in mice was associated with decreased levels of all three major lipid fractions and decreased odds of atherosclerotic cardiovascular disease. (Funded by Regeneron Pharmaceuticals and others; ClinicalTrials.gov number, NCT01749878 .).

Fasinumab (REGN475), an antibody against nerve growth factor for the treatment of pain: results from a double-blind, placebo-controlled exploratory study in osteoarthritis of the knee

The safety, tolerability, and efficacy of fasinumab (REGN475), a fully human monoclonal antibody against nerve growth factor, was evaluated for the treatment of pain in patients with osteoarthritis (OA) of the knee. This was a 24-week, double-blind, placebo-controlled, parallel-group, repeat-dose, exploratory study. Eligible patients 40 to 75 years of age with a diagnosis of OA of the knee and moderate to severe pain were randomized 1:1:1:1 to intravenous fasinumab 0.03, 0.1, or 0.3 mg/kg or placebo and received study drug on day 1 and day 57. Pain intensity was recorded daily using the numeric rating scale. Safety and tolerability, assessed by the incidence of treatment-emergent adverse events (TEAEs), was the primary study endpoint. Secondary study endpoints included the change from baseline in daily walking knee pain and the assessment of pain, function, and stiffness using the Western Ontario and McMaster Osteoarthritis (WOMAC) index. Baseline characteristics were similar among treatment groups (N=217). After 24 weeks, the incidence of TEAEs ranged from 66.1% to 75.0% in the fasinumab groups vs. 63.6% for placebo. The most common TEAEs included arthralgia, hyperesthesia, myalgia, peripheral edema, and joint swelling. Discontinuation for TEAEs occurred in 5.6% of fasinumab patients and 3.7% of placebo patients. All 3 doses of fasinumab were associated with significant (P<.05) improvements compared with placebo in walking knee pain and WOMAC total and subscale scores. Fasinumab was generally well tolerated, and was associated with a significant reduction in walking knee pain and an improvement in function for up to 8 weeks.

Rilonacept (interleukin-1 trap) in the prevention of acute gout flares during initiation of urate-lowering therapy: results of a phase II randomized, double-blind, placebo-controlled trial

OBJECTIVE

To evaluate the interleukin-1 inhibitor rilonacept (Interleukin-1 Trap) for prevention of gout flares occurring in the first few months following initiation of urate-lowering therapy.

METHODS

In this double-blind study, adult patients with hyperuricemia and gout were randomized to receive rilonacept administered subcutaneously once per week (loading dose 320 mg followed by 160 mg weekly) or placebo, and started on allopurinol (300 mg/day, titrated to serum urate <6 mg/dl). At study visits, physical and laboratory assessments were performed and information on any adverse events was ascertained.

RESULTS

Baseline characteristics were similar between the rilonacept and placebo groups (n = 41 and n = 42, respectively). The mean number of gout flares per patient through week 12 (primary efficacy end point) was markedly lower in the rilonacept group than in the placebo group (0.15 [6 flares] versus 0.79 [33 flares]; P = 0.0011). Fewer flares were observed with rilonacept as early as 4 weeks after initiation of treatment (P = 0.007). The proportion of patients experiencing a flare during the 12 weeks was lower in the rilonacept group than in the placebo group (14.6% versus 45.2%; P = 0.0037). No rebound in the flare rate was observed for 6 weeks after discontinuation of rilonacept or placebo at week 16. Adverse events were similar between groups, and no deaths or serious infectious adverse events were reported; the most common adverse events were infections (14.6% and 26.2% of rilonacept- and placebo-treated patients, respectively) and musculoskeletal disorders (14.6% and 21.4%, respectively). A higher percentage of rilonacept-treated patients (98%) compared with placebo-treated patients (79%) completed the primary 12-week evaluation period (P = 0.015).

CONCLUSION

The current findings indicate that rilonacept significantly reduces the frequency of gout flares during the initial period of treatment with urate-lowering therapy, with a favorable safety profile.

Cryopyrin-associated periodic syndromes: development of a patient-reported outcomes instrument to assess the pattern and severity of clinical disease activity

OBJECTIVE

Development of an instrument for characterization of symptom patterns and severity in patients with cryopyrin-associated periodic syndromes (CAPS).

METHODS

Two generations of daily health assessment forms (DHAFs) were evaluated in this study. The first-generation DHAF queried 11 symptoms. Analyses of results obtained with that instrument identified five symptoms included in a revised second-generation DHAF that was tested for internal consistency and test-retest reliability. This DHAF was also assessed during the initial portion of a phase 3 clinical study of CAPS treatment.

RESULTS

Forty-eight CAPS patients provided data for the first-generation DHAFs. Five symptoms (rash, fever, joint pain, eye redness/pain, and fatigue) were included in the revised second-generation DHAF. Symptom severity was highly variable during all study phases with as many as 89% of patients reporting at least one symptom flare, and percentages of days with flares reaching 58% during evaluation of the second-generation instrument. Mean composite key symptom scores (KSSs) computed during evaluation of the second-generation DHAF correlated well with Physician's Global Assessment of Disease Activity (r=0.91, p<0.0001) and patient reports of limitations of daily activities (r=0.68, p<0.0001). Test-retest reliability and Cronbach's alpha's were high (0.93 and 0.94, respectively) for the second-generation DHAF. Further evaluation of this DHAF during a baseline period and placebo treatment in a phase 3 clinical study of CAPS patients indicated strong correlations between baseline KSS and Physician's Global Assessment of Disease Activity. Cronbach's alpha's at baseline and test-retest reliability were also high. Potentially important study limitations include small sample size, the lack of a standard tool for CAPS symptom assessment against which to validate the DHAF, and no assessment of the instrument's responsivity to CAPS therapy.

CONCLUSIONS

The DHAF is a new instrument that may be useful for capturing symptom patterns and severity in CAPS patients and monitoring responses to therapies for these conditions.

Content and organization of the human Ig VH locus: definition of three new VH families and linkage to the Ig CH locus

We present a detailed analysis of the content and organization of the human immunoglobulin VH locus. Human VH genes representing five distinct families were isolated, including novel members belonging to two out of three of the known VH gene families (VH1 and VH3) as well as members of three new families (VH4, VH5, and VH6). We report the nucleotide sequence of 21 novel human VH genes, many of which belong to the three new VH gene families. In addition, we provide a preliminary analysis of the organization of these gene segments over the full extent of the locus. We find that the five multi-segment families (VH1-5) have members interspersed over nearly the full 1500-2000 kb of the VH locus, and estimate that the entire heavy chain locus covers 2500 kb or less. Finally, we provide the first report of the physical linkage of the variable and constant loci of a human Ig gene family by demonstrating that the most proximal known human VH segments lie within 100 kb of the constant region locus.

Size fractionation of anionic oligosaccharides and glycopeptides by high-performance liquid chromatography

A rapid method for the fractionation of anionic oligosaccharide and glycopeptide species on the basis of net carbohydrate content utilizing high-performance liquid chromatography has been developed. Amine-bearing bonded-phase columns are eluted with a mobile phase consisting of a water:acetonitrile gradient containing 3% acetic acid titrated to pH 5.5 with triethylamine. Phosphorylated and sialylated oligosaccharides within various charge classes differing in their hexose or hexosamine contents but bearing the same number of anionic species can be resolved without prior removal of the anionic moieties. Glycopeptides containing at least as many as six amino acids are also well fractionated on the basis of carbohydrate content. A variety of detection methods may be used and sensitivity in the subnanomole range is possible with fluorescent or radiolabeling techniques. This method offers a significant improvement in the rapidity and resolution attainable for the size fractionation of anionic complex carbohydrates.

Structures of the O-glycosidically linked oligosaccharides of human IgD

In the previous communication (Mellis, S. J., and Baenziger, J. U. (1983) J. Biol. Chem. 258, 11546-11556), the structures of the oligosaccharides present at the 3 asparagine glycosylation sites of a human IgD myeloma protein were defined. In this communication, we present the structures of the O-glycosidically linked oligosaccharides located in the hinge region of IgD:WAH. Three or four threonine residues and one serine residue in the region bear O-glycosidically linked oligosaccharides. Approximately 50% of these molecules have the structure Gal beta 1 leads to 3 GalNAc which is identical with the structure of the predominant oligosaccharide in the hinge region of human IgA1 myeloma proteins (Baenziger, J. U., and Kornfeld, S. (1974) J. Biol. Chem. 249, 7270-7281). The remainder of the oligosaccharides contain 1 or 2 residues of N-acetylneuraminic acid and have the structures NeuAc alpha 2 leads to 3Gal beta 1 leads to 3GalNAc (30%), Gal beta 1 leads to (NeuAc alpha 2 leads to 6)GalNAc (12%), and NeuAc alpha 2 leads to 3Gal beta 1 leads to 3(NeuAc alpha 2 leads to 6)GalNAc (8%). The sialylated molecules have not been encountered previously on other human immunoglobulin heavy chains. These structures, however, have been described on a number of secreted and membrane glycoproteins. Examination of oligosaccharides isolated from different subregions of the IgD hinge indicated that a specific distribution of the sialylated structures among the glycosylated amino acids of the hinge region is not likely.

Structures of the oligosaccharides present at the three asparagine-linked glycosylation sites of human IgD

The complete amino acid sequence of the human myeloma IgD:WAH has been determined and the sites of asparagine glycosylation identified as residues 354, 445, and 496 (Takahashi, N., Tetaert, D., Debuiere, B., Lin, L.-C., and Putnam, F. W. (1982) Proc. Natl. Acad. Sci. U. S. A. 79, 2850-2854). We have determined the structures of the oligosaccharides at each of these positions. Asn 354 bears oligosaccharides exclusively of the high mannose type containing from 5 to 9 mannose residues. Twenty per cent of the oligosaccharides at this site contain 1 glucose residue at the terminus of the branch emanating from the alpha 1 leads to 3-linked core mannose which is believed to reflect incomplete processing of the triglucosyl-high mannose oligosaccharide intermediate following transfer from dolichol to nascent peptide. Asn 445 and Asn 496 bear exclusively dibranched complex oligosaccharide structures; 30-40% of these molecules contain a bisecting GlcNAc-linked beta 1 leads to 4 to the innermost core mannose residue. At Asn 445, 40% of both the bisected and nonbisected oligosaccharides contain 1 residue of fucose on the Asn-linked GlcNAc and 50% bear a single N-acetylneuraminic acid residue. The oligosaccharides at Asn 496 are devoid of sialic acid and fucose. Thus, IgD:WAH is notable for the presence of virtually unprocessed oligosaccharide structures (glucosylated high mannose) on the same peptide backbone as extensively processed complex type molecules. The finding that each of the 3 Asn glycosylation sites of IgD:WAH bears either exclusively a complex or a high mannose type oligosaccharide indicates that there is considerable specificity in the glycosylation process. These oligosaccharides, nonetheless, display extensive microheterogeneity at each location.