Money and morals: ending clinical trials for financial reasons

Eyes that Do Not Meet the Eligibility Criteria of Clinical Trials on Age-Related Macular Degeneration: Proportion of the Real-World Patient Population and Reasons for Exclusion

Background

To evaluate the proportion of eyes that do not meet the eligibility criteria of clinical trials on neovascular age-related macular degeneration (AMD) and the reasons for exclusion.

Methods

This retrospective, observational study included 512 eyes of 463 patients diagnosed with treatment-naïve neovascular AMD. The proportion of eyes that did not meet the eligibility criteria of the Vascular Endothelial Growth Factor Trap-Eye: Investigation of Efficacy and Safety in Wet AMD (VIEW) studies were evaluated. The two most common reasons for exclusion were also evaluated in each subtype of neovascular AMD (typical neovascular AMD, polypoidal choroidal vasculopathy (PCV), and type 3 neovascularization).

Results

Among the 512 eyes, 229 (44.7%) did not meet the eligibility criteria. In all the included eyes, the most common reasons for exclusion were good or poor visual acuity (169 eyes, 33.0%), followed by the presence of subretinal hemorrhage (47 eyes, 9.5%). Moreover, good or poor visual acuity was the most common reason for exclusion in all three subtypes of neovascular AMD. The second most common reason was a fovea-involving scar or fibrosis in typical neovascular AMD, subretinal hemorrhage in PCV, and other vascular diseases affecting the retina in type 3 neovascularization.

Conclusions

Among the included cases, 44.7% did not meet the eligibility criteria for VIEW study, suggesting that the conclusion derived from clinical trials may not directly reflect the real-world outcomes. Additionally, the reasons for ineligibility differed among the different subtypes of neovascular AMD.

Radiation-induced brain injury: low-hanging fruit for neuroregeneration

Brain radiation is a fundamental tool in neurooncology to improve local tumor control, but it leads to profound and progressive impairments in cognitive function. Increased attention to quality of life in neurooncology has accelerated efforts to understand and ameliorate radiation-induced cognitive sequelae. Such progress has coincided with a new understanding of the role of CNS progenitor cell populations in normal cognition and in their potential utility for the treatment of neurological diseases. The irradiated brain exhibits a host of biochemical and cellular derangements, including loss of endogenous neurogenesis, demyelination, and ablation of endogenous oligodendrocyte progenitor cells. These changes, in combination with a state of chronic neuroinflammation, underlie impairments in memory, attention, executive function, and acquisition of motor and language skills. Animal models of radiation-induced brain injury have demonstrated a robust capacity of both neural stem cells and oligodendrocyte progenitor cells to restore cognitive function after brain irradiation, likely through a combination of cell replacement and trophic effects. Oligodendrocyte progenitor cells exhibit a remarkable capacity to migrate, integrate, and functionally remyelinate damaged white matter tracts in a variety of preclinical models. The authors here critically address the opportunities and challenges in translating regenerative cell therapies from rodents to humans. Although valiant attempts to translate neuroprotective therapies in recent decades have almost uniformly failed, the authors make the case that harnessing human radiation-induced brain injury as a scientific tool represents a unique opportunity to both successfully translate a neuroregenerative therapy and to acquire tools to facilitate future restorative therapies for human traumatic and degenerative diseases of the central nervous system.

Stem cell transplantation for spinal cord injury repair

Stem cells, especially neural stem cells (NSCs), are a very attractive cell source for potential reconstruction of injured spinal cord though either neuroprotection, neural regeneration, remyelination, replacement of lost neural cells, or reconnection of disrupted axons. The later have great potential since recent studies demonstrate long-distance growth and connectivity of axons derived from transplanted NSCs after spinal cord injury (SCI). In addition, transplanted NSCs constitute a permissive environment for host axonal regeneration and serve as new targets for host axonal connection. This reciprocal connection between grafted neurons and host neurons constitutes a neuronal relay formation that could restore functional connectivity after SCI.

Wrongful termination: lessons from the Geron clinical trial

Geron Corporation is a publically traded company that launched a phase I clinical trial of a human embryonic stem cell-based therapy for spinal cord injury. The company enrolled the first patient in October 2010 and stopped the trial 1 year later. The fifth patient had been enrolled but not transplanted when the company announced the trial's end. After discussions with clinical staff and family, an agreement was reached to add her to the cohort and proceed with the transplant. Two and half years later, the research is still waiting to restart. With this background in mind, we discuss the major ethical and social questions raised by the Geron case. We offer recommendations for institutional review boards and clinical sites as they deliberate approvals of early-phase trials in frontier medicine.