Ugandan biotechnology company Dei BioPharma says it has received preliminary feedback from the United States Food and Drug Administration on its development programme for PSI-033, a proposed biosimilar to the cancer immunotherapy medicine Yervoy.
The written comments, dated July 14, 2026, were issued ahead of a meeting between the company and the FDA scheduled for Wednesday, July 22.
The communication does not amount to FDA approval or clearance of PSI-033. Formal approval would require Dei BioPharma to submit a biologics licence application containing evidence that the proposed medicine is highly similar to Yervoy and has no clinically meaningful differences in safety, purity and potency.
Yervoy, whose active ingredient is ipilimumab, is manufactured by Bristol Myers Squibb and is used alone or in combination with other medicines to treat several cancers, including melanoma, kidney cancer, colorectal cancer and some forms of lung and liver cancer.
According to Dei BioPharma, the FDA’s preliminary comments addressed the company’s proposed formulation, manufacturing process, stability-testing programme and viral-safety studies.
The company said the regulator indicated that an animal study might not be required if laboratory and analytical evidence sufficiently demonstrates that PSI-033 is highly similar to Yervoy.
Dei BioPharma also said the FDA indicated that a separate clinical efficacy trial might not be necessary if analytical and pharmacokinetic studies demonstrate that there are no clinically meaningful differences between the proposed biosimilar and the reference medicine.
The FDA’s biosimilar framework allows the agency to determine that some studies are unnecessary when the totality of the available scientific evidence adequately demonstrates biosimilarity.
However, the company said the FDA recommended that pharmacokinetic studies be conducted among cancer patients rather than healthy volunteers because ipilimumab can cause serious immune-related side effects.
“The FDA’s detailed preliminary comments give us a clear, product-specific roadmap for strengthening our analytical programme, completing the required clinical studies and preparing PSI-033 for a future US licensing application,” Dei BioPharma founder and chief executive officer Dr Matthias Magoola said in a statement issued on Monday, July 20.
“We intend to address these recommendations with urgency and scientific rigour,” he added.
Magoola said the programme was part of the company’s wider objective of making biological medicines more affordable in countries where access remains limited.
“Our dream of making biological drugs available and affordable to more than 80% of countries that cannot afford these medicines is coming to fruition,” he said.
Dei BioPharma said it intends to submit an application for PSI-033 within approximately nine months. The timetable remains subject to the completion of the required analytical and clinical work and the company addressing the FDA’s recommendations.
FDA records show that Yervoy is licensed as an original biological product under the 351(a) pathway. As of July 21, 2026, the FDA’s public records did not show an approved ipilimumab biosimilar under the 351(k) pathway.
Bristol Myers Squibb reported worldwide Yervoy revenue of approximately $2.9 billion in 2025, equivalent to about Shs10.7 trillion using the conversion applied in the company statement.
The pharmaceutical company also reported about $10 billion in worldwide revenue from Opdivo, whose active ingredient is nivolumab, during the same year.
Dei BioPharma said it is also developing a proposed biosimilar version of Opdivo as part of a wider cancer-medicine portfolio.
“Our engagement with the FDA extends beyond PSI-033. This portfolio approach is central to our objective of building globally competitive biologics development and manufacturing capacity in Uganda while expanding access to essential medicines,” Magoola said.
Dei BioPharma operates a pharmaceutical and biotechnology manufacturing complex in Matugga, Wakiso District. Construction of the facility was launched in July 2021 by President Yoweri Museveni and William Ruto, who was then Kenya’s deputy president.