A recent study from Tata Memorial Hospital (TMH) suggesting that papaya leaf extract tablets can increase platelet counts in chemotherapy patients is under review after concerns were raised about its methodology and data interpretation.
The research, published in the Journal of Global Oncology, is being investigated following a request by Kochi-based hepatologist Dr Cyriac Abby Philips, popularly known as “The Liver Doc,” who questioned the study’s reproducibility and clinical conclusions. The journal has added a notice to the online paper advising readers to interpret the findings with caution while the review is underway.
The trial initially enrolled 219 patients, but after exclusions, the final analysis included 198 participants, with 69 assigned to the placebo group. The authors concluded that papaya leaf extract could serve as an affordable option for managing chemotherapy-induced thrombocytopenia (low platelet count) and may help patients continue chemotherapy without interruptions.
However, Dr Philips argued that the analysis excluded patients in the papaya treatment group who failed to recover before calculating the final results. According to him, this reduced the total number of participants while retaining all successful outcomes, increasing the apparent recovery rate from around 57% to approximately 64% without any additional recoveries. He also pointed out that some patients who recovered in the placebo group were excluded from the final analysis.
Responding to the criticism, the study’s lead author, Dr Vikas Ostwal, said the journal had sought clarifications as part of its standard review process and that the research team was preparing its response. He maintained confidence in the findings, stating that patients receiving the papaya extract tablets had consistently shown improved platelet counts by around the fourth day of treatment.
The papaya extract tablets used in the trial were supplied by Micro Labs Private Ltd., while the study received external funding from Zydus Pharma Pvt Ltd and Lupin Pharma Pvt Ltd. Lupin markets the papaya leaf extract under the brand name Caripapa. Dr Ostwal stated that although the researchers were aware of the funding sources, they were not aware that one of the sponsors commercially sold the product being evaluated.
Another concern raised by Dr Philips relates to the study’s primary endpoint. He said the trial was originally registered to measure platelet recovery on day seven, but the published analysis instead focused on day four, which had been designated only as an interim assessment. He argued that changing a primary endpoint after reviewing the data can introduce bias and increase the likelihood of reporting favourable results by chance.
A retired biostatistician from a public health institution reportedly agreed that altering the primary endpoint after data analysis, along with participant exclusions in both treatment and placebo groups, raises methodological concerns and may affect the reliability of the conclusions. The expert added that while the treatment may have genuine clinical potential, the statistical presentation requires careful evaluation.
Dr Amar Jesani, founder of the Indian Journal of Medical Ethics and a former member of Tata Memorial Hospital’s ethics committee, said that scientific disagreements are common but should be resolved through transparent evaluation. He suggested that releasing anonymised raw data could help independent experts assess the study objectively.
Experts noted that the journal’s ongoing investigation will be important in determining the validity of the findings. They also said that an independent, well-designed clinical trial would be necessary to confirm whether papaya leaf extract is effective in improving platelet counts among chemotherapy patients.
Commenting on the broader issue, Dr Philips said that studies from reputed institutions often receive greater trust, but peer review alone may not detect every methodological flaw or data inconsistency, as it largely relies on researchers accurately reporting their findings.