Earlier, Merrimack entered into an exclusive license and collaboration agreement with Baxter International for MM-398 outside of the US and Taiwan.
In May 2011, PharmaEngine licensed the development, manufacturing and commercialization rights of PEP02 in Asia and Europe to Merrimack for $220m plus royalties and sublicense revenue.
In May 2014, the two companies completed a global Phase III trial in patients with metastatic pancreatic cancer previously treated with gemcitabine-based therapy.
PharmaEngine president and chief executive officer Grace Yeh said: "This win-win partnership provided PharmaEngine with short term cash payments of $12m; mid-term investment of additional clinical trials by the two partners; and long-term upside of market access by Baxter which has global presence in the healthcare industry."
As part of the amendment, PharmaEngine will receive an immediate payment of $7m and a guaranteed payment of $5m upon the acceptance of the MM-398 new drug application (NDA) by the US Food and Drug Administration (FDA) or no later than 30 April 2015.
In addition, PharmaEngine is also eligible to receive up to $39.5m in sublicense revenue.
On the other hand, PharmaEngine is excluded from receiving sublicense revenue related to Merrimack’s upfront payment and up to $150m in development milestone payments from Baxter.
The company said that the remaining $200m of regulatory and sales milestones, as well as the tiered royalties, remain unchanged.
Totally, PharmaEngine is eligible to receive about $251.5m in the future, in addition to the license fees of $15m that were previously received under the agreement.