A Combined Phase 0/2 "Trigger" Trial of Niraparib in Combination with Radiation in Patients with Newly-Diagnosed Glioblastoma

PURPOSE/OBJECTIVE(S)

Poly ADP-ribose (PAR) polymerase (PARP) mediates DNA damage response. Niraparib is an investigational PARP1/2-selective inhibitor. We conducted a combined phase 0/2 study to evaluate niraparib pharmacokinetics (PK) and pharmacodynamics (PD) in patients with newly-diagnosed glioblastoma (GBM), graduating patients to a phase 2 study evaluating a therapeutic regimen of niraparib with concurrent conventionally-fractionated radiotherapy (RT) in O6-methylguanine methyltransferase (MGMT) unmethylated tumors exceeding a prespecified PK threshold in non-enhancing tumor.

MATERIALS/METHODS

Patients with presumed newly-diagnosed GBM were enrolled in a phase 0 study receiving 4 days of niraparib (300 or 200 mg QD) prior to planned resection 3-5 or 8-12 hours following the last dose. Tumor tissue (enhancing and non-enhancing regions), cerebrospinal fluid (CSF), and plasma were collected. Total and unbound niraparib concentrations were measured using validated LC-MS/MS methods. PARP inhibition was assessed by quantification of PAR induction after 10 Gy ex vivo irradiation in surgical tissue compared to non-irradiated control tissue. A PK 'trigger' determined eligibility for the therapeutic phase 2 expansion portion of the study. This was defined as unbound [niraparib] > 5-fold biochemical IC50 (i.e., 19 nM) in non-enhancing tumor. Patients with MGMT unmethylated tumors exceeding this PK threshold were eligible for expansion phase dosing of niraparib with concurrent RT followed by a maintenance phase of niraparib. Patients with MGMT methylated tumors were not eligible for the expansion phase and proceeded with temozolomide (TMZ) plus RT followed by maintenance TMZ. RT dose was 60 Gy in 30 fractions using volumetric-modulated arc therapy (VMAT).

RESULTS

All 29 patients enrolled in the phase 0 portion of the study met the PK threshold. In non-enhancing regions, the mean unbound concentration of niraparib was 258.2 nM. The suppression of PAR levels after ex vivo RT was observed in 79% of the patients (17/22). Sixteen patients had unmethylated tumors, and of those, 11 patients enrolled in phase 2. Five of the 6 initial patients enrolled in phase 2 experienced thrombocytopenia related to niraparib, and 3/5 cases were deemed serious and life-threatening. Consequently, starting dose in both phases was lowered to 200 mg, and no serious AEs were observed thereafter. At a median follow-up of 8.1 months [range: 6.0-12.9 months], 6-month PFS was 64% with 4 patients remaining on treatment and 5 patients ongoing survival follow-up.

CONCLUSION

Niraparib achieves pharmacologically-relevant concentrations in non-enhancing, newly-diagnosed GBM tissue in excess of any other studied PARP inhibitor. When delivered with concurrent RT, niraparib was well-tolerated, with low rates of grade 3+ toxicity. Initial clinical efficacy data are encouraging.

Injectable carbon nanotube-functionalized hydrogel as a tool for cardiac tissue engineering

Background/Introduction

Heart failure (HF) is an expensive major public health problem in the United States and around the world (1). The current treatments for HF are aimed at reducing symptoms, slowing disease progression, and reducing mortality and not aimed at repairing heart muscle or restoring function. Furthermore, even with these treatments, approximately half of patients with HF will die within 5 years of diagnosis (2). Cardiac transplantation remains the only definitive treatment for those affected with end-stage HF, but availability of donor hearts remains a major limitation (3).

Purpose

The ability of the adult heart to regenerate cardiomyocytes (CMs) lost after injury is limited, generating interest in developing tissue engineering therapies to avoid progression towards HF. Rigid carbon nanotubes (CNTs) scaffolds have been used to improve CMs viability, proliferation, and maturation (4), but require undesirable invasive surgeries for implantation. To overcome this limitation, we engineered an injectable reverse thermal gel (RTG) functionalized with CNTs (RTG-CNT) that transitions from a liquid-solution to a gel-based matrix shortly after reaching body temperature allowing for a liquid-based delivery rapidly followed by a stable-gel localization (5).

Methods and results

Here we show experimental evidences the RTG-CNT hydrogel, used as a three-dimensional (3D) niche to culture human induced pluripotent stem cells (hiPSC)-CMs, promotes hiPSC-CMs alignment and elongation with increased Cx43 localization and improved contraction function when compared with traditional two-dimensional (2D) fibronectin controls and plain 3D RTG system without CNTs. Moreover, the short-term (4-week) biocompatibility of the RTG-CNT hydrogel was also assessed in a mouse model (intracardial injection). The results confirmed that the RTG-CNT hydrogel is well tolerated by the cardiac tissue.

Conclusion

Our results indicated that the injectable RTG-CNT hydrogel has the potential to be used as a minimally invasive tool for cardiac tissue engineering efforts.

Funding Acknowledgement

Type of funding sources: Other. Main funding source(s): NATIONAL HEART, LUNG, AND BLOOD (NHLBI) INSTITUTE

A phase III randomized study comparing cisplatin and fluorouracil as single agents and in combination for advanced squamous cell carcinoma of the head and neck

PURPOSE

To determine whether combination chemotherapy is superior to single agents for recurrent/metastatic head and neck cancer, we compared the efficacy and toxicity of cisplatin (CP) and fluorouracil (5-FU), alone and in combination in a phase III trial.

PATIENTS AND METHODS

Two hundred forty-nine patients with recurrent head and neck cancer were randomized to one of three treatments: CP (100 mg/m2) and 5-FU (1 g/m2 x 4), CP, or 5-FU every 3 weeks.

RESULTS

The overall response rate to the combination (32%) was superior to that of CP (17%) or 5-FU (13%) (P = .035). Response was associated with good performance status (PS) but not with primary site, site of recurrence, histology, prior irradiation, or relative dose intensity. Median time to progression was less than 2.5 months, and there was no significant difference in median survival (5.7 months) among the groups. By multivariate analysis, patients with better PS and poorly differentiated tumors had superior survival. Hematologic toxicity and alopecia were worse in the combination arm.

CONCLUSION

Although the response rate to the combination of CP plus 5-FU was superior to that achieved with single agents, survival did not improve.

Permeability of the human round-window membrane to cationic ferritin

An ultrastructural study was done in three sequential steps to determine if the human round-window membrane was permeable to macromolecules. Cationic ferritin was first placed for one hour in the round-window niche of two live rhesus monkeys. The same tracer was then placed in the same manner in two rhesus monkeys that had been dead for one hour. In both groups, cationic ferritin was observed to traverse the round-window membrane through pinocytotic vesicles into the scala tympani. After establishing that the transport capabilities of the round-window membrane of the monkey remained present one hour after death, cationic ferritin was placed for one hour in the round-window niche of two humans who had been dead for 30 minutes and one hour. The tracer was observed to traverse the round-window membrane through pinocytotic vesicles into the scala tympani in both humans. This report may be the first to document morphologically the permeability of human round-window membranes to macromolecules.

Bateman UPF prosthesis in fractures of the femoral neck

The Bateman universal proximal femoral (UPF) endoprosthesis has been used in 225 patients for treatment of acute fractures of the femoral neck. In 156 patients with an average follow-up of 29 months and an average age of 79 years, there were no demonstrable advantages over the Moore prosthesis.

Treatment of Goodpasture's syndrome with plasmapheresis. A case report and review of the literature

A case is reported of antiglomerular basement membrane antibody-induced Goodpasture's syndrome in which the patient required hemodialysis and was treated with immunosuppressive agents and plasmapheresis. A severe (80 per cent) cresentic lesion was reversed, and creatinine was stabilized at 2.5 mg/dl at one year follow-up. Earlier reports of therapy without plasmapheresis showed that 88 per cent of the patients would either die or require long-term hemodialysis. Fifteen other reported cases of Goodpasture's syndrome in which the patients were treated with plasmapheresis are reviewed. When reported, short-term follow-up showed that nine of these patients were alive without need of dialysis, five wee receiving dialysis, and only two had died. This suggests that plasmaheresis and immunosuppressive therapy may reverse the renal lesion in some patients with Goodpasture's syndrome.

Evaluation of magnetic defocusing for a photomultiplier tube with large area semitransparent photocathode

Reduction of the effective cathode area of photomultiplier tubes is known to yield lower dark currents and an improved signal-to-noise ratio. This can be accomplished either by electrostatic or magnetic defocusing of the electron beam between the cathode and the first dynode. Three magnetic lenses with different field geometries were tried with an EMI 9558B photomultiplier tube, and a noise reduction of more than an order of magnitude was observed. Magnetic defocusing changes the pulse height characteristies of the tube as well and improves the discrimination between signal pulses and dark pulses when using simple pulse height discrimination techniques. If the tube is operated as a photon counter, the light-to-dark count ratio may be improved by nearly two orders of magnitude with the application of a suitable magnetic lens.