Oral octreotide absorption in human subjects: comparable pharmacokinetics to parenteral octreotide and effective growth hormone suppression

CONTEXT

Oral administration of a novel octreotide formulation enabled its absorption to the systemic circulation, exhibiting blood concentrations comparable to those observed with injected octreotide and maintaining its biological activity.

OBJECTIVES

The aim of the study was to determine oral octreotide absorption and effects on pituitary GH secretion compared to sc octreotide injection.

DESIGN

Four single-dose studies were conducted in 75 healthy volunteers.

INTERVENTION

Oral doses of 3, 10, or 20 mg octreotide and a single sc injection of 100 μg octreotide were administered.

MAIN OUTCOME MEASURE

We measured the pharmacokinetic profile of orally administrated octreotide and the effect of octreotide on basal and stimulated GH secretion.

RESULTS

Both oral and sc treatments were well tolerated. Oral octreotide absorption to the circulation was apparent within 1 h after dose administration. Escalating oral octreotide doses resulted in dose-dependent increased plasma octreotide concentrations, with an observed rate of plasma decay similar to parenteral administration. Both 20 mg oral octreotide and injection of 0.1 mg sc octreotide resulted in equivalent pharmacokinetic parameters [mean peak plasma concentration, 3.77 ± 0.25 vs. 3.97 ± 0.19 ng/ml; mean area under the curve, 16.2 ± 1.25 vs. 12.1 ± 0.45 h × ng/ml); and median time ≥ 0.5 ng/ml, 7.67 vs. 5.88 h, respectively). A single dose of 20 mg oral octreotide resulted in basal (P < 0.05) and GHRH-stimulated (P < 0.001) mean GH levels suppressed by 49 and 80%, respectively.

CONCLUSIONS

The results support an oral octreotide alternative to parenteral octreotide treatment for patients with acromegaly.

Lignocaine plasma levels following topical gel application in laparoscopic and hysteroscopic procedures

The study aim was to determine plasma lignocaine concentrations resulting from topical application of a newly formulated, sterile two-pack lignocaine gel in laparoscopic and hysteroscopic procedures. This was an open label single-centre study in which six female patients underwent laparoscopy and six underwent hysteroscopy. One venous blood sample was extracted pre-gel application, followed by 10 samples over a 24 hour period following application. Samples were centrifuged, stored at -20°C and subsequently analysed for lignocaine and its metabolite, monoethyl-glycinexylidide. Application of gel in doses between 2.7 and 5.8 mg/kg of lignocaine resulted in a maximum plasma concentration in any patient of 1520 ng/ml lignocaine and 240 ng/ml monoethyl-glycinexylidide. These maximum concentrations were recorded in a patient undergoing a laparoscopic procedure and patients undergoing hysteroscopic procedures all recorded lower maximum concentrations compared with patients undergoing laparoscopy; the maximum observed concentrations in a patient having a hysteroscopy were 420 ng/ml lignocaine and 56 ng/ml of monoethyl-glycinexylidide.A new sterile two-pack topical lignocaine gel, applied at the end of laparoscopic and hysteroscopic procedures in doses up to 5.84 mg/kg, resulted in plasma lignocaine levels below those known to have the potential to cause central nervous system toxicity.

T cells with chimeric antigen receptors have potent antitumor effects and can establish memory in patients with advanced leukemia

Tumor immunotherapy with T lymphocytes, which can recognize and destroy malignant cells, has been limited by the ability to isolate and expand T cells restricted to tumor-associated antigens. Chimeric antigen receptors (CARs) composed of antibody binding domains connected to domains that activate T cells could overcome tolerance by allowing T cells to respond to cell surface antigens; however, to date, lymphocytes engineered to express CARs have demonstrated minimal in vivo expansion and antitumor effects in clinical trials. We report that CAR T cells that target CD19 and contain a costimulatory domain from CD137 and the T cell receptor ζ chain have potent non-cross-resistant clinical activity after infusion in three of three patients treated with advanced chronic lymphocytic leukemia (CLL). The engineered T cells expanded >1000-fold in vivo, trafficked to bone marrow, and continued to express functional CARs at high levels for at least 6 months. Evidence for on-target toxicity included B cell aplasia as well as decreased numbers of plasma cells and hypogammaglobulinemia. On average, each infused CAR-expressing T cell was calculated to eradicate at least 1000 CLL cells. Furthermore, a CD19-specific immune response was demonstrated in the blood and bone marrow, accompanied by complete remission, in two of three patients. Moreover, a portion of these cells persisted as memory CAR(+) T cells and retained anti-CD19 effector functionality, indicating the potential of this major histocompatibility complex-independent approach for the effective treatment of B cell malignancies.

T cells with chimeric antigen receptors have potent antitumor effects and can establish memory in patients with advanced leukemia

Tumor immunotherapy with T lymphocytes, which can recognize and destroy malignant cells, has been limited by the ability to isolate and expand T cells restricted to tumor-associated antigens. Chimeric antigen receptors (CARs) composed of antibody binding domains connected to domains that activate T cells could overcome tolerance by allowing T cells to respond to cell surface antigens; however, to date, lymphocytes engineered to express CARs have demonstrated minimal in vivo expansion and antitumor effects in clinical trials. We report that CAR T cells that target CD19 and contain a costimulatory domain from CD137 and the T cell receptor ζ chain have potent non-cross-resistant clinical activity after infusion in three of three patients treated with advanced chronic lymphocytic leukemia (CLL). The engineered T cells expanded >1000-fold in vivo, trafficked to bone marrow, and continued to express functional CARs at high levels for at least 6 months. Evidence for on-target toxicity included B cell aplasia as well as decreased numbers of plasma cells and hypogammaglobulinemia. On average, each infused CAR-expressing T cell was calculated to eradicate at least 1000 CLL cells. Furthermore, a CD19-specific immune response was demonstrated in the blood and bone marrow, accompanied by complete remission, in two of three patients. Moreover, a portion of these cells persisted as memory CAR(+) T cells and retained anti-CD19 effector functionality, indicating the potential of this major histocompatibility complex-independent approach for the effective treatment of B cell malignancies.

PET, CT, and MR Imaging for Assessment of Thoracic Malignancy: Structure Meets Function

Imaging of patients with thoracic malignancy usually requires a multimodality approach. Each of these modalities has its own strengths and weaknesses. CT remains central to the staging and restaging of thoracic malignancies, but has recently been complemented with [18F]-2-fluoro-2-deoxy-D-glucose(FDG)-positron emission tomography (PET) imaging to maximize its potential. Furthermore, because FDG-PET/CT is useful at all stages of the workup and treatment of these patients, this modality has taken hold in the clinical realm for evaluation of patients with thoracic malignancy and is rapidly replacing PET-only imaging. MR imaging is also occasionally used in some patients with thoracic malignancies to improve disease staging or lesion characterization. PET/MR imaging may come to be used to evaluate patients with thoracic malignancies as well.

Selective corticosteroid and calcineurin-inhibitor withdrawal after pancreas-kidney transplantation utilizing thymoglobulin induction and sirolimus maintenance therapy

Of 25 simultaneous pancreas-kidney transplant (SPK) recipients treated with thymoglobulin induction, sirolimus and reduced-dose cyclosporine (CsA), 18 low-immune responders (non-African-Americans, PRA < 30%) were withdrawn from prednisone on post-transplant day 5, whereas seven high-immune responders continued on prednisone. Most high- and low-immune responder recipients were converted from CsA to mycophenolic acid (MPA) at six months post-transplantation. At a mean follow-up of 28 +/- 10 months, two pancreas grafts were lost to pancreatitis. There were no patient or kidney graft losses, but one acute rejection episode. At 28 +/- 11 months, all 18 low-responder recipients remain steroid-free. Twenty recipients (14 low and six high-immune responders) were converted from CsA to MPA. During conversion, immune response was monitored by Flow-PRA and T-cell stimulation (Cylex) assays. Nineteen of 20 recipients displayed a post-conversion PRA of 0%, whereas one highly sensitized patient expressed a post-conversion PRA of 67%. Fifty-eight percent of individual T-cell stimulation scores were in the hypo-responsive range. Twelve of 18 low-immune responders are both steroid and CsA-free at a mean follow-up of 17 +/- 13 months, whereas five of seven high-immune responders remain CsA-free at a mean follow-up of 11 +/- 10 months. These data suggest that thymoglobulin induction with combined sirolimus and CsA maintenance therapy permits immunosuppression minimization in selected SPK recipients.

An in vivo model for studying adherence of intestinal pathogens

A new method for preparing an isolated colonic loop in a living rabbit is described. The loop with its intact neurovascular supply can be used as as a "living test tube" to study the adherence of microorganisms to intestinal mucosa. Moreover, the clear colonic mucus produced by the loop can be used to study its physiochemical nature and protecting properties in health and disease.