In January, BMS signed a deal with AstraZeneca, worth up to $1.35bn (€989m), to co-develop and commercialise two of its late stage diabetes compounds - saxagliptin and dapaglifozin.
This time, Pfizer has penned two deals with BMS that could be worth over $1bn.
With research and development costs ever increasing, big pharma firms are on the look-out for ways to reduce the costs and risks associated with drug development.
Although partnerships are commonplace in the industry, it is much more unusual to see a collaboration between two of the industry's big players.
In its first deal with BMS, Pfizer will initially pay $250m to develop and commercialise apixaban, and BMS could also receive a further $750m based on various milestones.
Apixaban is a direct factor Xa inhibitor designed to regulate thrombin and so prevent potentially fatal blood clots.
"By combining our company's long-standing strengths in cardiovascular drug development and commercialisation with Pfizer's global scale and expertise in this field, we can maximize the potential benefits of apixaban for patients," said Jim Cornelius, CEO of Bristol-Myers Squibb.
"This collaboration supports our strategy to focus on serious diseases, maintain commercial emphasis on specialists and high-prescribing primary care physicians, and work with partners to offset the risks inherent with developing certain medicines."
If approved, apixaban could become the first oral treatment against blood clots approved in over 50 years.
However, it is expected to be beaten to market by Bayer's rivaroxaban, another direct factor Xa inhibitor.
Although both drugs are currently in Phase III trials, Bayer is planning to submit its drug for approval late this year in Europe and early 2008 in the US, with apixaban following in 2009.
It is hoped that by directly inhibiting a protein anticoagulation protein, the drugs may represent a more targeted approach compared to current therapies that affect multiple targets.
"Apixaban has the potential to be a best- in-class product and would represent an excellent strategic fit with our global cardiovascular franchise," said Pfizer's CEO, Jeffrey B. Kindler.
"This agreement demonstrates our commitment to pursue revenue opportunities both through our business development and external alliances as well as our internal research and development pipeline."
As part of the deal, Pfizer will also fund 60 per cent of planned development costs but will share commercialisation costs and profits 50-50 with BMS.
There are also several other anticoagulent drugs in development.
Boehringer Ingelheim's Rendix (dabigatran) is currently in multiple Phase III trials.
It is also an oral drug but instead of interacting with factor Xa, it works by directly inhibiting thrombin (factor IIa).
The second deal concerns a Pfizer discovery programme that includes preclinical compounds with the potential to treat metabolic disorders, including diabetes and obesity.
In this case, BMS will pay Pfizer - the much lower figure of $50m reflecting the early development stage - and Pfizer has agreed to fund the early stage R&D before sharing costs at Phase III development.
Both these later costs and any profits will be shared 60-40 with Pfizer getting the larger share.
After a difficult year in 2006, BMS were the subject of merger rumours with Sanofi-aventis reportedly keen.
Although these rumours have now died down, BMS is clearly still eager to share some of the development costs and risks faced by pharma companies.