The H-1B status can be extended even if you have lost or misplaced your passport. You , however, should obtain a new passport which will be required when you request an H-1B visa with the U.S. consulate in your home country.
It shouldn't have any affect but you are urged to report the stolen passport and apply for a new one from your country's embassy ASAP.
If by "extension is in progress" the H-1B petition is yet to be filed, the I-129 petition should note that your passport has been stolen but that you are working on obtaining a new passport. The petitioner can even submit a police report regarding the theft. Otherwise, work on obtaining a new passport.
Years licensed, work experience, educationLegal community recognition
Peer endorsements, associations, awardsLegal thought leadership
Publications, speaking engagementsDiscipline