Portable Blood Monitoring Device Improves Acceptability, Feasibility of Treatment With Clozapine for Schizophrenia

Caroline Cassels

June 04, 2010

June 4, 2010 (New Orleans, Louisiana) — A portable device that analyzes blood cell count using a single drop of capillary blood may improve initiation of, and treatment adherence to, clozapine in patients with treatment-resistant schizophrenia, new research suggests.

A small case series study presented here at the American Psychiatric Association (APA) 2010 Annual Meeting illustrates the potential utility of the device in the 20% to 30% of patients with schizophrenia who fail to respond to conventional antipsychotics.

According to principal investigator Jimmi Nielsen, MD, Aalborg Psychiatric Hospital, Aarhus University Hospital in Denmark, up to 60% of treatment-resistant patients with schizophrenia respond to clozapine, making it the drug of choice in this patient population.

However, he said, because of an increased risk for agranulocytosis and the resulting need for mandatory blood monitoring, its use has been restricted to patients who fail to respond to at least 2 antipsychotic medications.

"Clozapine is highly underutilized. In Europe it is a very cheap drug because it is generic, but it is not marketed at all," Dr. Nielsen told Medscape Psychiatry.

Compliance a Major Issue

Mandatory blood monitoring, which requires regular attendance at a laboratory for venous blood sampling, is another major barrier to the drug's use. In Europe patients are required to have weekly blood sampling for 18 weeks after initiation of treatment and then monthly for as long as they are taking the drug.

According to Dr. Nielsen, many patients whose conditions are well controlled with clozapine eventually find the blood testing regimen onerous and fail to comply

"Very often it takes a tremendous effort to motivate these patients to get to the lab, and sometimes we have to discontinue clozapine because we cannot motivate them to have regular blood tests done, with the result that they have a psychotic relapse and have to be admitted to hospital," said Dr. Nielsen.

Similarly, in treatment-resistant patients who have not initiated clozapine therapy mandatory blood monitoring can also be a major deterrent. "Many of these patients have a very good chance of responding to clozapine, so it is very important to offer them the drug, but blood monitoring can get in the way," said Dr. Nielsen.

Immediate Results

CHEMPAQ XBC allows capillary blood monitoring at the point of care with a single finger prick so patients can have the procedure done in the office of their health care provider and receive immediate results. Dr. Nielsen said he first saw the device 2 years ago in an advertisement and followed up with the company to see if it could be used in this patient population.

"At that time I was employed in a psychosis unit and had a lot of patients treated with clozapine and I saw this advertisement for this point of care device that could test white blood cell count as well as granulocyte count, and it seemed to be exactly what we needed for our patients," he said.

The study presented at APA's annual meeting focused on 2 cases. Case 1 was a 40-year-old man who had been treated with clozapine for 8 years with a good response. During this time he had no admissions and his schizophrenia was considered to be in remission.

Before treatment with clozapine he had had several admissions and suicidal behavior and did not respond to other antipsychotic drugs. However, he had to be constantly reminded to undergo the mandatory blood monitoring, and this problem was worsening over time with the result that the psychiatrist was about to discontinue clozapine therapy.

Once CHEMPAQ was applied the patient was able to have his blood tested in the physician's office during his monthly visits.

Case 2 was a 41-year-old man diagnosed as having paranoid schizophrenia who was considered a "revolving door" patient. He had been treated with several antipsychotic medications but with only a partial response, making him a candidate for clozapine. However, he refused clozapine for 8 years because of the mandatory blood monitoring. The researchers report he was "especially fearful of losing too much blood during blood sampling."

However, once the patient was offered capillary blood monitoring with CHEMPAQ XBC he subsequently accepted treatment with clozapine, the researchers report.

After 2 weeks of treatment with clozapine at a dose of 100 mg/day, his paranoid delusions disappeared and he was discharged after 1 month to an outpatient clinic, the researchers report.

"He continued to comply with the blood monitoring, which was done in the outpatient clinic. After 2 months of treatment he began to paint, which he had not been doing since the onset of schizophrenia," the investigators reported.

Dr. Nielsen noted that the direct costs of CHEMPAQ XBC are comparable to venous blood testing but that the device may result in significant health savings by reducing relapses and hospitalization.

On the basis of these initial findings, Dr. Nielsen along with colleague Christoph U. Correll, MD, Zucker Hillside Hospital, North Shore-Long Island Jewish Health System, Glen Oaks, New York, are currently conducting an ongoing study of approximately 100 subjects with treatment-resistant schizophrenia comparing venous vs capillary blood monitoring. Results are expected at the end of 2010.

Dr. Nielsen reports he has received research grant support from CHEMPAQ.

American Psychiatric Association (APA) 2010 Annual Meeting: NR6-18. Presented May 26, 2010.