The landscape of oncology clinical trials in Africa over the last three decades (1995-2025).

e23236 Background: Africa is home not only to 20% of the world’s population but also to the highest human genetic diversity. Genomics increasingly drives cancer drug discovery, biomarker development, and dose optimization. This study reviews Africa’s representation in high-impact oncology clinical trials. Methods: We identified all oncology clinical trials published in The Lancet and The New England Journal of Medicine (NEJM) between 1995 and 2025, and retrieved full-text PDFs from the journals' websites. Using an LLM (Gemini-2.5-Flash), structured variables, including trial phase, cancer type, enrollment countries, and participant race and/or ethnicity, were automatically extracted from texts, tables, and figures. Trials were stratified by decade (1995–2005, 2006–2015, and 2016–2025) to evaluate temporal trends. Results: Among the 1,385 global oncology trials reviewed, only 66 (4.8%) were conducted in African countries: 16 in 1995–2005, 30 in 2006–2015, and 20 in 2016–2025. The trials occurred in just 11 African countries, with South Africa alone accounting for 56 (84.8%) of these 66 trials. Egypt contributed 6 trials (9.1%), and Mauritius 5 trials (7.6%). Early-phase trials were rare: only 1 Phase 0 (1.5%) and 1 Phase 2 (1.5%) trial were identified, while the majority were Phase 3 (64 trials, 97.0%). Across all periods, Phase 3 studies dominated. The trials covered 58 distinct cancer types, but the most frequent were squamous cell carcinoma of the head and neck (n = 3), non-small cell lung cancer (n = 2), colorectal adenomas (n = 2), and chronic lymphocytic leukemia (n = 2). The number of African trials increased from 16 (24.2%) in 1995–2005 to 30 (45.5%) in 2006–2015, before declining to 20 (30.3%) in 2016–2025. Geographic diversity improved modestly: 5 countries participated in the first two periods, compared with 7 in the most recent period. Conclusions: This study shows that cancer research continues to overlook Africa and its genetic diversity. This omission demands deliberate investment in clinical trial infrastructure, regulatory harmonization, diaspora-academic partnerships, and early-phase trial capacity in Africa to ensure the development of globally representative, biologically robust cancer therapeutics. Characteristic Overall (N=66) 1995–2005 (n=16) 2006–2015 (n=30) 2016–2025 (n=20) Global trials, n 1,385 – – – Trials with African sites, n (%) 66 (4.8) 16 (24) 30 (46) 20 (30) African countries, n 11 5 5 7 Trial phases 0, 2, 3 3 2, 3 0, 3 0, n (%) 1 (1.5) 0 0 1 (5.0) 2, n (%) 1 (1.5) 0 1 (3.3) 0 3, n (%) 64 (97.0) 16 (100) 29 (96.7) 19 (95.0) Cancer types, n 58 14 29 18 Most frequent cancers HNSCC, NSCLC, CLL, CRC, Prostate NSCLC, CLL HNSCC, CRC, Breast NSCLC, Prostate, TNBC Trials by country, n (%) South Africa 56 (84.8) 14 (87.5) 28 (93.3) 14 (70.0) Egypt 6 (9.1) 2 (12.5) 4 (13.3) 0 Mauritius 5 (7.6) 0 1 (3.3) <jats:td cols