TOKYO, Dec 23 (Reuters) - Japanese shares rose on Thursday as a strong overnight finish on Wall Street lifted investor sentiment, but concerns over the domestic spread of the Omicron COVID-19 variant capped gains. The Nikkei share average (.N225) gained 0.4% to 28,665.97 by 0203 GMT, while the broader Topix (.TOPX) was up 0.44% at 1,980.23. "The market tracked the gains in the U.S. market but I would say investors are still buying back stocks that were sold off," said Takatoshi Itoshima, strategist at Pictet Asset Management. The Nikkei, which fell 1.4% in the past week, is set to post a third straight session of gains. The main U.S. indexes staged a broad rally overnight on upbeat economic data and a South African study that suggested reduced risks of hospitalization and severe disease in people infected with the Omicron variant versus Delta. In Japan, commodities-related shares led gains in the 33 industry subindexes on the exchange, with oil and coal explorers (.IMING.T) and trading firms (.IWHOL.T) rising 2.42% and 1.05%, respectively. Tokyu Fudosan Holdings (3289.T) jumped 4.89% to lead gainers on the Nikkei after the property developer agreed to sell its Tokyu Hands home interior store chain. Weighing on investor sentiment, however, Japan reported its first instance of community spread infection from the Omicron. read more Drugmakers (.IPHAM.T) fell, dragged down by Eisai (4523.T), which tumbled 8.42% after a Japanese government panel said that inconsistent trial results made it difficult to determine the efficacy of an Alzheimer"s treatment developed by the Japanese company and Biogen Inc (BIIB.O). read more Astellas Pharma (4503.T) slipped 1.38%, while Takeda Pharmaceutical (4502.T) edged up 0.1%.