Gensia earns FDA clearance for pharmacologic stressor combo

California medical products developer Gensia Automedics is preparing to take on the market for pharmacologic stress agents with a novel product that combines a stressor with a device that automatically regulates the flow of the drug. Gensia Automedics received clearance last month for a new drug application for its GenESA system, which will compete with stressors on the market from Du Pont Merck Radiopharmaceuticals and Fujisawa.

Pharmacologic stress agents are used in nuclear medicine cardiology studies to stimulate the heart rates of patients who are unable to exercise. Of the estimated 3 million to 3.5 million cardiac perfusion tests performed in the U.S. each year, 25% to 30% use pharmacological stress agents, according to Gensia. GenESA now joins Du Pont's I.V. Persantine and Fujisawa's Adenoscan in targeting this market.

GenESA differs from the Du Pont and Fujisawa products in several ways, however, according to Paul Cayer, vice president of the GenESA system and business development. For instance the stress agent used in the GenESA system is arbutamine, which Gensia claims has advantages over other products. Arbutamine is a catecholamine, which more closely simulates the cardiac effects of exercise than the Du Pont and Fujisawa drugs, Gensia claims. Other drugs are vasodilators, which simulate exercise by dilating the coronary vessels, producing flow differences that are comparable to exercise, according to Cayer.

The second aspect of the GenESA system is also unique. Rather than requiring clinicians to infuse arbutamine manually, the system uses a delivery device that regulates drug flow to the patient so that the rise in the patient's heart rate more closely simulates that which occurs during exercise. To control the arbutamine delivery, the GenESA uses biofeedback from the patient, in the form of heart rate and blood-pressure readings that the device collects during the procedure.

Gensia refers to GenESA as a closed-loop system and believes that it will make it easier for clinicians to administer and monitor pharmacological stress exams. Patients should also benefit because the system makes it harder for clinicians to overstimulate the heart rate, Cayer said.

GenESA is the first of a series of closed-loop drug delivery systems under development at Gensia Automedics, which was formed to specialize in closed-loop technology. The company is a subsidiary of pharmaceutical firm Gensia Sicor, which has transferred several new technologies to Gensia Automedics, such as a closed-loop system for administering heparin, an anticoagulant agent. GenESA is the company's first product to receive FDA clearance, and the company also believes that GenESA is the first new drug/new device combination to win the agency's go-ahead. Gensia Sicor plans to spin off Gensia Automedics into a separate company.

In addition to nuclear cardiology, Gensia believes GenESA can be used in stress echo applications, which were covered in last month's clearance, making arbutamine the only approved stress agent for the echo market. The echo market could have even more potential than nuclear cardiology, because existing approved stress agents don't work well with echocardiography and no commercially available stress agent was approved for echo applications until GenESA was cleared, Cayer said. The company believes that the benefits of arbutamine as a stress agent could make it more appropriate for stress echo than other products on the market, such as the vasodilators.

Gensia Automedics plans to sell GenESA directly and has built a sales force for the product. The device will sell for around $15,000, with the price of arbutamine ranging from $125 to $150 a dose. Gensia will also offer capital leasing programs for the device.

The company will be going up against two well-established competitors in the pharmacologic stressor market, but Cayer believes that the novelty of GenESA will give the company an edge.

"It is going to be challenge for us, but we have certain advantages. Arbutamine works very differently than the vasodilators," Cayer said. "The primary selling point is the physiologic response of the drug, and the second point is the device."