In this preclinical project we intended to verify the cooling performance and comfort of the COOLPREVENT system prototype developed by BrainCool AB on healthy individuals. The results of this preclinical project demonstrate that COOLPREVENT can reduce skin temperature by 14.5 ± 3.8°C and 10.7 ± 1.7°C in the hands and feet, respectively. The discomfort reported by subjects was to the extent that it did not cause intolerable pain and subjects were able to complete the cooling process for 60 minutes.
Chemotherapeutics are effective in arresting the progression of cancer because they are often designed to differentially target and eliminate rapidly dividing cancer cells. Despite the positive effects of chemotherapeutic approaches in the cancer-fighting arena, there are also various deleterious side effects such as pain, hair loss, fatigue and CIPN that negatively affect normal cells and structures of the body. CIPN is a frequent, dose-dependent complication of anticancer drugs, including platinums, taxanes, epothilones, vinca alkaloids, and newer agents, such as bortezomib (10). CIPN not only leads to dose reduction or discontinuation of treatment but also decreases the quality of life of cancer survivors. CIPN occurs in ~ 20% of patients given standard doses of chemotherapy and in over 80% of patients treated with high doses (2, 11, 12).
CIPN occurs when peripheral nerves are damaged, and presents clinically as deficits in sensory, motor, and sometimes autonomic function. Sensory disturbances range from a mild tingling sensation to spontaneous burning pain and hypersensitivity to stimuli. These symptoms often affect both hands and feet and may spread into a ‘glove/stocking’ distribution (12). There is currently no preventative treatment that is approved and there are no active medicines to treat CIPN if it occurs. The need is thus great in both general oncology and hematology, and for patients a preventative treatment would be preferable.
Localized cooling is a method which has demonstrated clinical efficacy and is hypothesized to lead to a cascade of events. In other words, cooling will bring down tissue temperature causing vasoconstriction of blood vessels in distal limbs. The reduction of blood flow to the hands and feet means that there is less damage of chemotherapy agents incurred by nerve fiber endings in the hands and feet and ultimately preventing the risk of CIPN (5, 13). However, current methods for inducing cooling are based on the use of ice packs in the form of gloves and socks and ice-water baths to cool the hands and feet; methods which are difficult to control and can therefore be painful and intolerable for patients. As well, using these methods are limited in terms of time as the ice starts to melt and loose its cooling capacity. Thus, there is an urgent need for a technique that can deliver cooling to the patient in a controlled and tolerable manner.
To answer to this need, BrainCool AB has developed COOLPREVENT, a mechanical cooling prototype that cools the hands and feet in a controlled, convenient, and tolerable manner. Based on the findings of this study COOLPREVENT is: 1. Tolerable for individuals- COOLIMB attachments will allow hands and feet temperatures to drop for a minimum of 10°C during 60 minutes of cooling. 2. Controllable and convenient to implement in the treatment room- by being ice-free (no-melting, no need for clean-up). According to our preliminary findings, we hope that COOLPREVENT can potentially provide protection against CIPN offered by cooling. It is expected that reduction in these side-effects will in turn lead to higher treatment compliance with higher survival rates of patients with cancer and improved quality of life during and after treatment.
This study had several limitations. First, as a result of a manufacturing defect in one of the cooling gloves, there was not enough contact between the skin and the cooling material. We have been in communication with the manufacturing company and the issue is being resolved to ensure it does not occur in later stages of clinical testing. Second, this preclinical study was conducted on three healthy subjects and thus results should be interpreted with caution. To be able to make more reliable statements regarding the effect of cooling using COOLPREVENT, larger number of patients undergoing chemotherapy must be tested.
Therefore, results from this preclinical feasibility study are promising and demonstrate that the COOLPREVENT prototype system can be administered to reduce skin temperature by at least 10°C. Our future goal is to validate the use of COOLPREVENT in clinical trials with the intention of using this system to prevent or treat CIPN in patients undergoing chemotherapy.