Inhomogeneous Diastereomeric Composition of Mongersen Antisense Phosphorothioate Oligonucleotide Preparations and Related Pharmacological Activity Impairment

Mongersen is a 21-mer antisense oligonucleotide designed to downregulate Mothers against decapentaplegic homolog 7 (SMAD7) expression to treat Crohn's disease. Mongersen was manufactured in numerous batches at different scales during several years of clinical development, which all appeared identical, using common physicochemical analytical techniques, while only phosphorous-31 nuclear magnetic resonance (³¹P-NMR) in solution showed marked differences. Close-up analysis of 27 mongersen batches revealed marked differences in SMAD7 downregulation in a cell-based assay. Principal component analysis of ³¹P-NMR profiles showed strong correlation with SMAD7 downregulation and, therefore, with pharmacological efficacy in vitro. Mongersen contains 20 phosphorothioate (PS) linkages, whose chirality (Rp/Sp) was not controlled during manufacturing. A different diastereomeric composition throughout batches would lead to superimposable analytical data, but to distinct ³¹P-NMR profiles, as indeed we found. We tentatively suggest that this may be the origin of different biological activity. As similar manifolds are expected for other PS-based oligonucleotides, the protocol described here provides a general method to identify PS chirality issues and a chemometric tool to score each preparation for this elusive feature.

Explaining biosimilars and how reverse engineering plays a critical role in their development

INTRODUCTION

Biologicals are protein-based therapeutics consisting of larger and more complex structures than small molecule medicines. As the patents for originator biological therapeutics expire, biosimilar products are licensed for the same indications as their marketed reference biologics across different specialities. Owing to the complex nature of the manufacturing process for a biological therapy compared to conventional chemically synthetized medicines, the development of biosimilars is more complicated and costly than the manufacture of generic small molecules.

AREAS COVERED

The manufacturing process of the originator biologic is in most cases largely unknown to biosimilar developers and therefore reverse engineering through extensive analysis of the originator is a fundamental and critical step for successful biosimilar development. In this review, the authors examine the abbreviated roadmap for biosimilar approval which must be underpinned by the same rigorous standards that apply to all biological medicines. They discuss various aspects of biosimilar manufacturing with a focus on reverse engineering.

EXPERT OPINION

The biosimilar approval pathway places a greater emphasis on preclinical assessments in comparison to the development of originator biologics. Multiple comparative clinical studies add little to the confirmation of the efficacy of the molecule under study whilst adding considerably to the cost and time of bringing a biosimilar into clinical use. A successful demonstration of biosimilarity to the reference product is therefore essential at a structural and functional level but this could not be achieved without well-designed and quality-driven reverse engineering of the originator production process.

Biosimilars

Biological therapies have widened the therapeutic armamentarium for immune-mediated inflammatory diseases, providing in many cases a broad range of treatment options with different mechanisms of action. The widespread use of biological agents in systemic lupus erythematosus is currently limited to belimumab and rituximab, although results of promising larger Phase III clinical trials are awaited or have been recently circulated, especially for anti-cytokine therapies. The loss of exclusivity over the last years for several originator biologics has started the successful introduction of biosimilar products into clinical practice. There is an abbreviated pathway to biosimilar approval, but this is underpinned by the same standards of pharmaceutical quality, safety and efficacy that apply to all biological medicines. Nevertheless, there are unique reasons why development of biosimilars may be particularly challenging in lupus.

A review article on biosimilar infliximab SB2 in the treatment of rheumatoid arthritis

TNF inhibition has had a major impact as an approach for treating rheumatoid arthritis and a series of biologic agents directed against TNF have been developed for clinical use. Infliximab, a chimeric monoclonal antibody against soluble and membrane-bound TNF-α, was the biopharmaceutical to lead this ‘biologics revolution’. However, with expiration of patent protection of the originator medicinal product, biosimilar versions of infliximab have been developed through biosimilarity studies and randomized controlled trials aiming to assess pharmacokinetic, pharmacodynamic and clinical equivalence to their originator (reference product) in patients with moderate-to-severe disease activity. This review summarizes the clinical development of SB2, a biosimilar of infliximab, in rheumatoid arthritis.

Necrotizing Panniculitis as an Uncommon Manifestation of Acute Pancreatitis

Pancreatic panniculitis is a rare disorder affecting 2–3% of patients with pancreatic disease. The findings are characterized by tender, erythematous, subcutaneous nodules which may undergo spontaneous ulceration with discharge of brownish and viscous material derived from colliquative necrosis of adipocytes. The lesions are usually localized in the lower limbs, although they may also extend to the buttocks and also involve the trunk, upper limbs and scalp. They can precede overt pancreatic disease in 40% of cases. The typical histological features observed in these lesions are characterized by necrotic adipocytes with absent nuclei (better known as ‘ghost cells’) in the context of a predominantly lobular panniculitis.

We describe the case of a 78-year-old cirrhotic woman admitted to our department with abdominal pain affecting the upper abdomen and a 3-day fever. On physical examination, multiple tender erythematous nodules, with irregular margins, were present on the pretibial regions of both lower legs, ranging in size from 0.8 to 1.5 cm. Pancreatic amylase and lipase were elevated and abdominal computed tomography revealed acute pancreatitis with oedema, focal gland enlargement of the pancreatic tail and perivisceral inflammation. Histological examination of the lesions was consistent with a diagnosis of necrotizing granulomatous panniculitis.

Weekly low-dose methotrexate for reduction of Global Initiative for Asthma Step 5 treatment in severe refractory asthma: study protocol for a randomized controlled trial

BACKGROUND

Patients with chronic severe asthma (CSA) have a crippling disease and current available treatments are not satisfactory. Thus, management of CSA remains a major unmet need. Although the evidence from existing randomized controlled trials fails to support a definite role for immunomodulatory drugs in these patients due to major methodologic drawbacks, findings with low-dose methotrexate (MTX) are encouraging. However, larger and well-designed clinical trials are required to establish the beneficial role of MTX in CSA, and for the detection of the key characteristics of those who are going to respond to this drug.

METHODS/DESIGN

Patients will be recruited from the accessible asthmatic patients lists of tertiary referral centers. All patients will meet the stringent diagnostic criteria for CSA, including the requirement for the regular use of Global Initiative for Asthma (GINA) Global Strategy for Asthma Management and Prevention Step 5 medications (oral prednisone and/or omalizumab). The experimental design of the proposed study will take the form of a double-blind parallel-randomized placebo-controlled trial consisting of a total of eight visits, including run-in and run-out periods. Patients will be randomly allocated to receive either MTX or a matched placebo once a week as an add-on therapy to their existing medication after run-in. Physiological, laboratory and clinical assessments will be measured regularly throughout the study and compared with baseline assessments.

DISCUSSION

We expect that MTX will reduce Step 5 medications dosage in patients with CSA without compromising the overall disease control. Improvement in several indicators of asthma severity and control will be also investigated.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT02124226 (assigned 25 April 2014).

Clinical trial: ulcerative colitis maintenance treatment with 5-ASA: a 1-year, randomized multicentre study comparing MMX with Asacol

BACKGROUND

5-ASA-MMX (1.2 g/tablet) is a 5-aminosalicylic acid formulation, designed for once-daily dosing in the treatment of ulcerative colitis.

AIM

To evaluate the efficacy and safety of 5-ASA-MMX (2.4 g/day, once daily), compared with Asacol (2.4 g/day, twice daily) in the maintenance of left-sided UC, through a double-blind, double-dummy, parallel-group, randomized, comparator study.

METHODS

In all, 331 patients with UC were randomized to receive either 5-ASA-MMX 2.4 g/day, once daily, or Asacol 2.4 g/day, twice daily, for 12 months. All patients were in remission for >or=1 month prior to the trial, with >or=1 documented relapse in the previous year. The co-primary endpoints of this study were the proportion of patients in clinical, and clinical and endoscopic remission following 12 months' treatment.

RESULTS

In the intent-to-treat population, excluding those with major protocol deviations, 68.0 and 65.9% patients in the 5-ASA-MMX and Asacol groups, respectively, were in clinical remission (P = 0.69), and 60.9 and 61.7% of patients, respectively, were in clinical and endoscopic remission (P = 0.89). Diary card data revealed statistically significant treatment differences favouring 5-ASA-MMX. Both treatments were similarly tolerated.

CONCLUSIONS

Once-daily 5-ASA-MMX is similarly effective with a comparable safety profile to Asacol administered twice daily, for the maintenance treatment of ulcerative colitis.

5-aminosalicylic acid enhances anchorage-independent colorectal cancer cell death

Resistance to anoikis, the cell death triggered by the loss of anchorage to the substratum, is an essential prerequisite in the proliferation and diffusion of colorectal cancer (CRC) cells. We examined whether 5-aminosalicylic acid (5-ASA), a drug that seems to reduce the risk of colitis-associated CRC, enhances CRC cell anoikis. To this end, Colo205 cells were treated with 5-ASA in the presence or absence of inhibitors of caspases (zVAD-fmk) and reactive oxygen species (ROS). We demonstrate that 5-ASA enhances Colo205 cell death. Although 5-ASA induces dissipation of mitochondrial transmembrane potential and caspase-3 activation, zVAD-fmk does not completely prevent the 5-ASA-induced cell death. 5-ASA also enhances the synthesis of ROS. However, inhibitors of ROS reduce the fraction of 5-ASA-induced Colo205 cell death but do not confer protection. In contrast, the 5-ASA-mediated Colo205 cell death is preventable by Bcl-2 over-expression. These data suggest a mechanism by which 5-ASA interferes with colon carcinogenesis.

Silencing of SH-PTP2 defines a crucial role in the inactivation of epidermal growth factor receptor by 5-aminosalicylic acid in colon cancer cells

Recent studies have suggested that 5-aminosalicylic acid (5-ASA) inhibits colorectal cancer (CRC) development. However, the mechanism underlying the antineoplastic effect of 5-ASA remains unknown. We here examined the effect of 5-ASA on epidermal growth factor receptor (EGFR) activation, a pathway that triggers mitogenic signals in CRC cells. We show that 5-ASA inhibits EGFR activation, through a mechanism that does not rely on CRC cell death induction. 5-ASA enhances the activity, but not expression, of phosphorylated (p)-EGFR-targeting phosphatases (PTPs), and treatment of cells with PTP inhibitors abrogates the 5-ASA-mediated EGFR dephosphorylation. Both SH-PTP1 and SH-PTP2 interact with EGFR upon 5-ASA treatment. However, knockdown of SH-PTP2 but not SH-PTP1 by small interference RNAs prevents the 5-ASA-induced EGFR dephosphorylation. Finally, we show that 5-ASA attenuates p-EGFR in ex vivo organ cultures of CRC explants. Data indicate that 5-ASA disrupts EGFR signalling by enhancing SH-PTP2 activity, and suggest a mechanism by which 5-ASA interferes with CRC growth.

[Ca 19-9 in the diagnosis of pancreatic carcinoma]

This study was undertaken in order to ascertain the role of CA 19-9 in pancreatic cancer diagnosis. Therefore CA 19-9 was determined in the sera of 83 control subjects, 108 patients with pancreatic cancer, 112 with chronic pancreatitis and 126 with extrapancreatic diseases. Sensitivity, specificity and accuracy in detecting pancreatic cancer were: 75%, 86% and 61% respectively. The receiver-operating characteristic curves showed that CA 19-9 is able to well discriminate pancreatic cancer from controls; satisfactorily it differentiated pancreatic malignancy from chronic pancreatitis and other benign extrapancreatic diseases. Extrapancreatic neoplasms were not accurately separated. No difference was detected in CA 19-9 levels between pancreatic cancer patients with or without hepatic metastases. We can conclude that CA 19-9 is a test for pancreatic malignancy with a satisfactory sensitivity and specificity in respect of other pancreatic and extrapancreatic benign pathologies; the presence of hepatic metastases is only one of the factors which may increase its serum levels.