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My first experience with the withdrawal of a medicine was just a few months after I started working in 1975. We had an injectable antibiotic Reverin (rolitetracycline) which had two variations: intravenous and intramuscular. One day, we received the instructions that the product was being withdrawn and that we had to go to every pharmacy in our area, count the physical stock of the product, and make a credit note, one copy for the pharmacy and one for the office. It was not a widespread product, and the job was done rather quickly.
In 2006, the Ministry of Health (DRAP came later) issued withdrawal notice for gatifloxacin, a quinolone group antibacterial. The MoH invited all companies who were manufacturing it. We gathered at the MoH Islamabad, and the DG Health explained that the product had issues with blood glucose levels and was being withdrawn. Some people resisted and offered that a black box warning may be added. The DG politely disagreed that most of our people cannot read English so it will not be effective. The product was withdrawn.
Weight reduction drugs have been successively withdrawn. Fenfluramine, Phentermine, Sibutramine, were all axed after having been available for several years. Rofecoxib became a blockbuster in anti-inflammatory segment but had to be withdrawn. Terfenadine, the first claimed non-sedating antihistamine was withdrawn after about 12 years of use and several deaths. Rosiglitazone became quite popular as an antidiabetic but was withdrawn in 2010. Zantac (ranitidine) was withdrawn in 2020 after remaining topline product in anti-ulcer therapy for over 30 years. Prepulsid (cisapride), gastroprokinetic, also was culled after becoming a blockbuster.
Some drugs have been withdrawn in several countries but are still available in Pakistan. DRAP still think these are safe enough to stay on the market. Nimesulide is still available here. Dipyrone remained available for almost 20 years after having been withdrawn from most markets. Sparfloxacin was withdrawn by USFDA, but it is still selling here.
How many products have been withdrawn so far? The number will depend upon the time fame which is selected. The evaluation processes have been evolving over the decades resulting in better understanding and handling of withdrawals.
Common Reasons for Withdrawal
- Safety Concerns: These include adverse events such as severe side effects, increased risk of mortality, and potential for abuse and addiction. Contributing factors include inadequate preclinical testing, incomplete clinical trials, and limitations of post-marketing surveillance.
- Insufficient Efficacy: These products failed to demonstrate sufficient efficacy in clinical trials or real-world use. This may be due to poor study design, inadequate patient selection, or flawed data analysis.
- Manufacturing Issues: These include problems with product quality, contamination, and deviations from good manufacturing practices (GMP). Contributing factors include inadequate quality control procedures and lack of oversight by regulatory agencies.
- Commercial Reasons: These include low sales, poor market reception, and competition from other products.
Why Were Issues Not Found Earlier?
- Limitations of preclinical testing: Animal models do not always accurately predict human response. These are mostly toxicology studies to determine toxic doses. Such doses shall never be given to humans.
- Limited scope of clinical trials: Clinical trials typically involve a small number of participants and may not detect rare but serious side effects. Clinical trials are also done under rather controlled conditions with careful selection of participants. The true picture emerges when the drug is used in the real world, under real-life conditions, and by large number of patients from different ethnic origins.
- Bias in clinical trial data: Positive results are more likely to be published than negative ones. Another variation is that the statistical presentation of the results is done in a way so as to show the drug in a positive light.
- Post-marketing surveillance limitations: Passive reporting systems rely on healthcare professionals to report adverse events, which can lead to underreporting. Adverse drug reporting system is extremely poor or non-existent in countries like ours.
- Lack of transparency: Pharmaceutical companies may be reluctant to disclose safety concerns or negative data. The most common way is to share only that data which does favor the drug.
- Forceful marketing: Aggressive marketing campaigns are run at the launch to generate huge number of prescriptions and business. The issues may remain masked for quite some time.
The withdrawal of pharmaceutical products highlights the importance of robust safety and efficacy testing. It also underscores the need for improved post-marketing surveillance and greater transparency from pharmaceutical companies.
Recommendations
- Increase the stringency of preclinical testing and clinical trials. Further guidelines should be worked out and issues.
- Implement larger and more diverse clinical trials to capture rare but serious side effects. The publishing and interpretation of trials should also be done more clearly.
- Improve post-marketing surveillance systems to encourage active reporting of adverse events. Pharmacovigilance is an upcoming field and it should be further strengthened.
- Enhance transparency by requiring pharmaceutical companies to disclose all clinical trial data, including negative results.
- Implement stricter regulations and penalties for violations of guidelines at any and all stages.
Sum Up
The withdrawal of pharmaceutical products underscores the need for continuous vigilance and improvement in the drug development and approval process. By addressing the limitations of current systems and promoting transparency, we can ensure the safety and efficacy of medications for patients.
Concluded.