Pfizer Korea has failed to reduce the number of target participants in post-marketing surveillance (PMS) of Xeljanz (tofacitinib), an oral drug for rheumatoid arthritis.
Earlier, the company requested the Ministry of Food and Drug Safety to adjust the number of enrollment for Xeljanz PMS from 3,000 to 700, citing difficulty in recruiting patients.
However, the ministry’s Central Pharmaceutical Affairs Advisory Committee concluded that it was not reasonable to cut the number of PMS cases from 3,000 to 700 because Xeljianz needed a collection of long-term safety data. The committee also noted that the company needed to collect safety information and mitigate risks under a risk management plan (RMP) continuously.
Under the ministry’s drug reassessment criteria, a drugmaker should collect 3,000 PMS cases for a reevaluation of a drug if it is the world’s first drug developed in Korea, or a new Korean drug being developed overseas, or a new drug that has not passed three years since the development in a foreign country. It is the minimal number of PMS participants in which adverse events with an expression rate of 0.1 percent could be detected statistically.
One panelist said it was not easy to rule on the validity of the cut in enrollment without any statistical evidence or advice of a statistics expert.
Another panelist said, “Rheumatoid arthritis treatment works differently in every person, and some patients cannot use such drugs due to the side effects of injections. For a customized treatment, we need drugs that have a different mechanism.”
A third panelist supported the company’s request for the reduction of PMS enrollment to 700 from 3,000.
“It will be impossible to recruit 3,000 patients until the reevaluation period. Physicians recommend collecting side effects voluntarily, but some medical institutions find it difficult to participate in PMS. In such hospitals, a physician can hardly participate in the PMS,” a fourth panelist said. “Completing our review with only 700 cases seems to be fine. Physicians are already using the drug and well aware of its side effects.”
The committee’s opinions were sharply divided, and Pfizer’s request for the enrollment cut earned only three votes out of the seven panelists. The other four opposed Pfizer’s idea.
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Pfizer’s rheumatoid arthritis drug Xeljanz 5mg