JERUSALEM, Dec 29 (Reuters) - Israel's Oramed Pharmaceuticals (ORMP.O) said on Wednesday its Oravax Medical unit signed a deal with Vietnam's Tan Thanh Holdings for the pre-order of 10 million doses of its oral COVID-19 vaccine that is in clinical trials.

The agreement gives Tan Thanh, a drug distributor, the right to sell Oravax’s oral vaccine in development throughout the Association of Southeast Asian Nations (ASEAN), which includes Brunei, Cambodia, Indonesia, Laos, Malaysia, Myanmar, the Philippines, Singapore, Thailand and Vietnam, Oramed said.

"The parties have agreed to negotiate follow-on orders potentially worth hundreds of millions of dollars," it said, adding the ASEAN region has a prospective patient population of about 660 million.

Nadav Kidron, chief executive of Oramed, said its oral COVID vaccine is undergoing Phase I clinical trials and results should be available in early 2022. The vaccine has been shown to work in animal tests, he said.

As long as Phase I results are as expected, Kidron believes more countries will be interested since the new technology is not likely to require as many boosters as current vaccines. "The idea is that you take it and that's going to be your dosing and you're done," he said.