Maker, experts, civic groups express different views

“Tasigna” – the chronic myeloid leukemia therapy of Novartis which won approval as a medicine more than a decade ago -- is now at the center of a dispute over its efficacy.

The drug won the approval from the Ministry of Food and Drug Safety in 2007 as the secondary treatment for chronic myeloid leukemia that shows resistance and intolerance to Gleevec. Three years later, it obtained the conditional approval as the primary therapy by adding indications that can be directly used for “newly diagnosed patients” – not as the secondary treatment for those who shows no effects with Gleevec.

Tasigna

In approving Tasigna as the primary therapy in 2010, the ministry attached a condition that Novartis Korea should submit a final report on the long-term survival rate of patients with chronic myeloid leukemia who participate in Phase 3 clinical trials. The company agreed to hand in the data of five years.

A controversy arose, however, as Novartis Korea asked to extend the deadline for submitting the final report. Some industry watchers suspected the company’s failure to meet these conditions might have been behind its request for delaying the deadline.

Novartis Korea made the request, noting that its headquarter office had agreed to confirm the long-term survival rate of 10 years, not five. The ministry found the request appropriate and extended the deadline to 2019. In this process, Novartis Korea has reportedly submitted the data of five, six and seven years.

However, the Pharmaceutical Association for Healthy Society, a civic organization composed of pharmacists, raised suspicion that Novartis Korea wanted to extend the date because it couldn’t satisfy requirements for the conditional approval. The association contended the Novartis Korea should have submitted the five-year data and disclosed its contents as agreed and additionally send the 10-year data later on.

“As promised, Novartis Korea should reveal the results of clinical trials. The ministry granted permission for Tasigna as the first therapy based on Phase 2 clinical trials, and not Phase 3 trials. The company ought to send the final report based on the initial conditions,” the group said Wednesday. “We doubt its intention not to come up with the results. This might be because the company confirmed its efficacy but found safety problems or judged maintaining the current state of conditional approval is more advantageous to the company.”

Both ministry and the maker appeared embarrassed with these allegations.

“We didn’t think it would cause any problems,” a ministry official said. “We will release the contents of discussion soon to dissolve misunderstanding.”

Novartis Korea also tried to justify its move. “Our bid to renew the deadline to submit the final report was legally approved by final decision made by a review committee that includes outside experts,” the company said in a press release. “At that time, we added a condition to hand in interim reports for clinical trials to MFDS on a yearly basis. We will provide the data collected for 96 months this month.”

It went on to say, “We released the data of efficacy and safety evaluation trials collected for 72 months in the European Hematology Association in 2015 and published the 5-year information in the international medical journal, Leukemia, last year. All data show that efficacy and safety of Tasigna are superior to the existing therapy Gleevec.”

Novartis Korea says the ongoing hubbub is due to misunderstanding. Experts, however, attribute the controversy to the limit of second-generation therapy to treat chronic leukemia, like Tasigna.

“Most experts agree that there isn’t much difference in survival rate for patients with chronic myeloid leukemia between the second-generation drugs, Tasigna and Spryvel Tab, and Gleevec,” said a professor at the hemato-oncology division of a university hospital in Seoul. “Their survival period has increased by decades of years with the release of Gleevec. It is true Tasigna produces effects quite rapidly, which is why it obtained approval in Europe. But it 's hard to confirm the difference in the survival period with data collected for five years.”

The expert then commented on different side effects between the two therapies. “We can’t ignore the side effects, either. Although Gleevec generates many side effects at the early stage of intake, they don’t much affect our daily life,” he said. “On the other hand, 1 percent of the Tasigna users suffer from clogs in blood vessels and the users of another second-generation treatment, Spryvel Tab, find water fills their lungs.”

Put together, it is necessary to keep a close watch in the long run, he added.

Copyright © KBR Unauthorized reproduction, redistribution prohibited