Onyx Pharmaceuticals, the South San Francisco, California-based com­pany that developed and now mar­kets Kyprolis (car­filz­o­mib), announced yesterday eve­ning that it is being acquired by Amgen.

Amgen (NASDAQ:AMGN), which is based outside of Los Angeles, is the world’s largest bio­tech com­pany.

Within the multiple myeloma community, Amgen is known most for its anemia medications – Aranesp (darbe­poetin alfa) and Epogen (epoetin alfa, also mar­keted as Procrit and Eprex) – as well as its drugs that in­crease the body’s pro­duc­tion of white blood cells – Neupogen (filgra­stim) and Neulasta (pegfilgrastim).

In addi­tion, Amgen mar­kets Xgeva (denosumab), a bone-strengthening agent cur­rently approved for use in cancer patients whose disease has spread into the bone marrow.  Xgeva has been tested as a potential alter­na­tive to bis­phos­pho­nates, such as Aredia (pamidronate) and Zometa (zoledronic acid), as a treat­ment for bones weakened by multiple myeloma.  However, Xgeva is not yet approved for use in myeloma patients.

Yesterday’s announcement of the Onyx ac­qui­si­tion concludes a process that began two months ago, when Amgen made an unsolicited offer for Onyx (NASDAQ:ONXX).  After it received Amgen’s offer, Onyx effectively put itself up for sale, soliciting competing bids from a number of other com­pa­nies.

Ultimately, Amgen prevailed in the bidding war for Onyx, with a winning offer of $125 per share -- just slightly more than the original, unsolicited $120-per-share offer it made for Onyx in June.

Amgen’s ac­qui­si­tion of Onyx is expected to be finalized, subject to regulatory approval, by the beginning of the fourth quarter this year.

What Does The ac­qui­si­tion Mean For The Myeloma Community?

The Onyx ac­qui­si­tion is unlikely to have any significant near-term impact relevant to the myeloma community

Kyprolis, the myeloma treat­ment Onyx developed and now sells in the United States, will con­tinue to be available, both before and after Amgen wraps up its ac­qui­si­tion of Onyx.

Plans for the launch of Kyprolis outside of the United States also should be unaffected by the ac­qui­si­tion.  Currently, analysts expect Kyprolis to launch in Europe no earlier than the second half of 2015.

The intermediate-term impact of the ac­qui­si­tion may be positive – particularly for myeloma patients over­seas.

Prior to the ac­qui­si­tion, Onyx had planned to launch Kyprolis on its own in most over­seas mar­kets.  This plan would have required Onyx to put in place, and then build up, a substantial amount of administrative and sales infrastructure in other countries, potentially slowing the launch of Kyprolis after its approval in Europe and elsewhere.

If, however, the Amgen ac­qui­si­tion of Onyx proceeds as planned, Kyprolis will launch over­seas under the care of Amgen, which already has extensive operations across the globe.  Those resources will be available to prepare for, and then support, the launch of Kyprolis in mar­kets outside the U.S. once regulatory approvals are secured.

This potential impact of the Onyx ac­qui­si­tion was highlight by Dr. Robert Orlowski, a myeloma specialist at the MD Anderson Cancer Center in Houston.  He told The Beacon, “This ac­qui­si­tion could be a very positive step because Amgen's global experience can help expand access to [Kyprolis], both in the United States and especially in other countries.”

The primary uncertainty surrounding the Onyx ac­qui­si­tion’s impact on the myeloma community lies in its longer-term impact.

Until yesterday’s announcement, Onyx had in place rather aggressive plans to further develop Kyprolis and also to develop a potential new myeloma treat­ment, oprozomib, which is similar to Kyprolis, but can be taken orally rather than having to be injected or infused, as is the case with Kyprolis.

Once the Onyx ac­qui­si­tion is completed, an open question will be whether Amgen will be as focused as Onyx has been in pursing the further devel­op­ment of Kyprolis and opozomib.

As Dr. Robert Orlowski noted, the ac­qui­si­tion could “strongly benefit the further devel­op­ment of [Kyprolis], and especially of oprozomib, given the experience of Amgen in the oncology field, and their ability to facilitate more studies than could be supported by Onyx.  However, for these benefits to be realized, Amgen will need to make a commitment to maintain the current aggressive devel­op­ment plan that was put in place by Onyx.”

The question of commitment and focus is prompted, in part, by another pharma­ceu­tical com­pany ac­qui­si­tion that took place a bit more than five years ago – the ac­qui­si­tion of Millennium Pharmaceuticals, the com­pany that developed Velcade (bor­tez­o­mib), by Takeda Pharmaceutical in May 2008.

As is expected to be the case with the Onyx ac­qui­si­tion, Takeda’s ac­qui­si­tion of Millennium had little im­medi­ate impact on Velcade’s availability or sales.

However, some might argue that Millennium has not been as aggressive as it might have been as an in­de­pen­dent com­pany in developing or acquiring the rights to potential new myeloma treat­ments.

Development of the com­pany’s successor to Velcade, ixazomib (MLN9708), was slow for many years, and the launch of the drug is still not expected until 2015.  In addi­tion, Millennium has not been as aggressive as, for example, Celgene, in making deals to give it access to potential new myeloma treat­ments initially developed by other com­pa­nies.

Celgene, which is in­de­pen­dent, cur­rently mar­kets thalidomide, Revlimid (lena­lido­mide), and Pomalyst (poma­lido­mide) as treat­ments for myeloma.  It has struck a number of deals in recent years to acquire mar­ket­ing rights to potential new treat­ments for myeloma, including a recent licensing agreement for MOR202 (see related Celgene press release).

Thus, although the near- and intermediate-term impact of the Amgen ac­qui­si­tion of Onyx on the myeloma community is likely to be neutral to positive (particularly over­seas), the longer-term impact is less certain.  It will depend on the extent to which Amgen, once it takes over responsibility for Onyx’s prod­uct portfolio, is able to remain focused on developing Onyx’s existing portfolio while also developing potential new treat­ments for myeloma.

For addi­tional in­­for­ma­tion about the Onyx acquisition, see the related press release from Onyx.