The $8m extension brings Rhythm's B round to $33m and the total raised to $73m in less than two years.

US-based diabetes and obesity treatment company Rhythm Pharmaceuticals has extended its series B round by $8m by ading Pfizer Venture Investments, the corporate venturing unit of the eponymous local drugs company, to the syndicate.

The extension brings Rhythm’s B round to $33m and the total raised to $73m in less than two years.

In June, Ipsen, a France-based pharmaceutical company, helped Rhythm raise $25m.

Ipsen was joined in the series B round by Rhythm’s existing investors, venture capital firms MPM…