Pfizer to Acquire Medivation, Developer of Enzalutamide

Laura van’t Veer, MD

Ian Read

Pfizer has announced plans to acquire the biopharmaceutical company Medivation, which is the developer of the androgen receptor inhibitor enzalutamide (Xtandi). Under the terms of the agreement, Pfizer will pay $81.50 per share in cash for Medivation, totaling approximately $14 billion. Both companies agreed to the transaction, which is expected to complete later this year.

“The addition of Medivation will strengthen Pfizer’s Innovative Health business and accelerate its pathway to a leadership position in oncology, one of our key focus areas, which we believe will drive greater growth and scale of that business over the long-term," Ian Read, chairman and chief executive officer at Pfizer, said in a statement. "This transaction is another example of how we are effectively deploying our capital to generate attractive returns and create shareholder value.”

Enzalutamide is approved as a treatment for patients with metastatic castration-resistant prostate cancer (CRPC), with extensive studies ongoing for the agent across other indications. Prior to the acquisition, Medivation had announced plans to initiate the phase III ENDEAR trial to explore enzalutamide as a treatment for patients with triple-negative breast cancer. This study was expected to begin enrollment in the fourth quarter of 2016.

In addition to enzalutamide, Medivation also holds worldwide rights to the PARP inhibitor talazoparib (BMN-673), which was initially developed by BioMarin Pharmaceuticals. This agent is being explored in the I-SPY2 trial in combination with low-dose irinotecan as a neoadjuvant treatment for newly diagnosed patients with locally advanced HER2-negative breast cancer. Additionally, Medivation was engaged in conversations with the FDA on the development of registrational trials for talazoparib for patients with CRPC and small cell lung cancer.

Pidilizumab is the third promising agent in Medivation's portfolio. It was licensed by the company in October 2014 from CureTech. A phase II study is exploring pidilizumab for patients with diffuse large B-cell lymphoma (DLBCL), following a partial clinical hold that was meant to address the mechanism of action for the medication. Pidilizumab was initially believed to be a PD-1 inhibitor; however, this was later proven to be untrue. The antibody does appear to possess immune-mediate anti-tumor activity, although it is not through the PD-1 pathway.

Antitumor activity was shown for pidilizumab in studies for DLBCL and recently reported findings for pediatric patients with diffuse intrinsic pontine glioma (DIPG). In 72 patients with DLBCL, the 18-month progression-free survival rate was 72% and the overall survival (OS) rate was 84% with pidilizumab. In a small study of 9 children with DIPG, pidilizumab showed a mean OS of 15.6 months. The event-free survival was 12 months, and 3 patients remained progression-free after 24 months.

“We believe the combination with Pfizer is the right next step in our growth trajectory and is a testament to the passion and dedication by which the Medivation team has delivered on our mission to profoundly transform patients’ lives through medically innovative therapies,” David Hung, MD, founder, president and CEO of Medivation, said in a statement. “We believe that Pfizer is the ideal partner to extend the reach of our blockbuster Xtandi franchise and take our promising, late-stage assets—talazoparib and pidilizumab–to their next stages of development so that they can be made available to patients as quickly as possible.”

Pfizer will add Medivation's oncology products to its own broad portfolio, which includes palbociclib (Ibrance), sunitinib (Sutent), and crizotinib (Xalkori), along with other medications. Additionally, in its pipeline, Pfizer, in collaboration with Merck KGaA, has numerous phase III studies ongoing that are exploring the PD-L1 inhibitor avelumab as a treatment for patients with non—small cell lung cancer, gastric cancer, ovarian cancer, renal cell carcinoma, and urothelial carcinoma. Pfizer is also currently exploring a number of biosimilars, including phase III studies looking at biosimilar versions of bevacizumab, rituximab, and trastuzumab.

“The proposed acquisition of Medivation will build upon Pfizer’s success with our Ibrance launch in HR+/HER2- metastatic breast cancer and with our strong immuno-oncology portfolio, and will transform Pfizer into a leading oncology company,” Albert Bourla, group president, Pfizer Innovative Health, said in a statement. “Ibrance and Xtandi are anchor brands in breast and prostate cancer, respectively, giving Pfizer leadership in two hormone-driven cancers. Similar to Ibrance in the breast cancer setting, Xtandi is being explored for its potential to move from metastatic prostate cancer to treat earlier stages of non-metastatic prostate cancer."

The FDA is currently reviewing a supplemental application for enzalutamide that is intended to add data from the phase II STRIVE and TERRAIN studies to the label for the medication. In TERRAIN and STRIVE, enzalutamide was compared with bicalutamide for patients with prostate cancer who progressed following an LHRH analog therapy or surgical castration. Patients had metastatic disease in TERRAIN and non-metastatic prostate cancer in STRIVE. The agency is scheduled to make a decision on the application by October 22, 2016.