TAIPEI: Shares of OBI Pharma Inc yesterday fell by the maximum daily limit of 10 percent to close at NT$613, after the company on Sunday released discouraging results on the second and third-phase clinical trials of a new breast cancer drug, OBI-822.
OBI-822 remains an effective treatment option and the trial’s less promising than expected outcome stemmed from a number of factors, OBI Pharma chairman Michael Chang told an investors’ conference yesterday.
The drug is designed to target Globo H, an oligosaccharide tumor antigen, by triggering the human body’s immune system to generate antibodies that activate cytotoxic T cells to destroy cancer cells, and more than 80 percent of the participants in the trials had generated immune system responses, he said.
Among the participants who showed immune responses, most had made good progress in recovery, while maintaining a safe level of toxicity of the drug.
“About 20 percent of participants did not generate immune responses, and their results should not have been included in the study,” Chang said.
The parameters of the study were set in 2009, and the company elected to go ahead with the trials even though it had discovered flaws in the methodology, he said.
In addition, the study had neglected to select participants based on whether they showed an ample presence of Globo H, Chang said.
Immune responses are not statistically significant without the oligosaccharide, he said.
The flawed design of the study prematurely ruled out many potential participants before they had time to go through the eight-to-nine-week dormant period it is believed to take for the immune responses to develop, he said.
Chang said that he and the company’s other major stakeholders are planning to initiate a share buyback program.
Academia Sinica President Wong Chi-huey, a close collaborator with the company, said he considers an 80 percent immune response as a statistically successful outcome, in particular among people in the more terminal stages of their diseases, who have diminished immune systems.
The objective of clinical trials is to determine which drugs prove to be effective and the focus should be placed on the outcome of participants who have developed an immune response, Wong said.
Excluding those without an immune response would present a more statistically significant outcome, Wong said, and he urged health authorities to devise new criteria for different treatments.
Yesterday’s plunge in OBI Pharma shares dragged down the biotechnology and medical care sub-index on the Taipei Exchange, which fell 5.17 percent to 178.9 points, the lowest since November last year, with many other high-priced sector leaders also seeing steep declines, TPEX data showed.
Analysts said that they do not expect a catastrophic crash in OBI Pharma share prices, as the company’s backers include the deep-pocketed Runtex Group.