Pfizer's Three-Pronged Oncology Strategy Includes Expanding Ibrance, Xtandi, Developing Blockbuster Combos

As Pfizer Inc.continues to grow its oncology business, it's pushing both new molecules and expanding the indications of its approved drugs.

Andy Schmeltz, global president of Pfizer Oncology, described the company's strategy as a three-pronged approach at a May 15 press briefing at Pfizer's New York headquarters ahead of the American Society of Clinical Oncology (ASCO) annual meeting June 1-5 in Chicago.

The first prong of Pfizer's strategy is to build on anchor treatments for breast and prostate cancer. The company is looking to extend the indications for Ibrance(palbociclib), a CDK4/6 inhibitor approved for metastatic breast cancer, and Xtandi(enzalutamide), approved for metastatic castration-resistant prostate cancer, for use in earlier non-metastatic cancer.

A supplemental application for the expanded Xtandi indication is pending at FDA with a user fee date in July after the company released positive Phase III data from the PROSPER trial last year, which showed improvement in metastasis-free survival in patients with non-metastatic, castration-resistant prostate cancer.  The company also has a PARP inhibitor, talazoparib, in development for breast and prostate cancer. (Also see "Pfizer Poised To PROSPER From Xtandi In Expanded Indication" - Scrip, 14 Sep, 2017.)

Schmeltz said the second prong is to deliver precision medicines in lung cancer and hematologic malignancies.

The company is developing a follow-on to Xalkori(crizotinib), its first-in-class anaplastic lymphoma kinase (ALK) inhibitor, in lung cancer. The new compound, lorlatinib, was developed to address people who have developed resistance to ALK inhibitors. It received priority review as a second-line treatment for patients with ALK-positive metastatic non-small cell lung cancer (NSCLC) and has a user fee date in August. (Also see "Keeping Track: Vitaros Reenters The Wilderness, Remoxy Gives It A Fourth Try, And Two Novel Approvals" - Pink Sheet, 19 Feb, 2018.)

Pfizer also filed a new drug application for dacomitinib, a pan-human epidermal growth factor receptor (EFGR) tyrosine kinase inhibitor for first-line treatment of locally advanced or metastatic NSCLC. It received a breakthrough therapy designation and priority review and has a user fee date in September. (Also see "Keeping Track Of Good News For AstraZeneca, Pfizer, Promius, And Sunovion" - Pink Sheet, 8 Apr, 2018.) 

Pfizer will present overall survival results from a study of dacomitinib versus AstraZeneca PLC'sIressa(gefitinib) at ASCO. The company also will present Phase II results for Ibrance in combination with Eli Lilly & Co.'sErbitux(cetuximab) in platinum-resistant human papillomavirus (HPV)-negative recurrent/metastatic head and neck squamous cell carcinoma.

In hematology, Schmeltz said the company has quietly built a presence withBosulif(bosutinib), approved for Philadelphia chromosome-positive chronic myelogenous leukemia. Last year, FDA approvedBesponsa(inotuzumab ozogamicin) for treatment of adults with relapsed or refractory B-cell precursor acute lymphoblastic leukemia (ALL). And the agency okayed the return to market of the acute myeloid leukemia (AML) treatmentMylotarg(gemtuzumab ozogamicin), which had been withdrawn in 2010. (Also see "Pfizer's Mylotarg Likely To Get New Orphan, Biologics Exclusivities" - Pink Sheet, 8 Sep, 2017.)

As for the third prong, it encompasses the next wave of innovation in immuno-oncology, which is focused on finding the right combination of therapies. Pfizer is looking at combinations of its PD-L1 inhibitorBavencio(avelumab), which it gained through a partnership with Merck KGAA, with targeted agents such as Pfizer'sInlyta(axitinib) and talazoparib, and a triple combination with OX40 and 4-1BB, co-stimulatory receptors on T cells.

Aiming For Five Blockbusters

Mikael Dolsten, president of Pfizer Worldwide Research and Development, noted that Pfizer has been pursuing a step change in R&D productivity, and oncology products now comprise the top five of 15 actual and expected blockbuster drugs at the company. The company's oncology revenues grew 33% to $6.06bn in 2017, powered by Ibrance and Xtandi. 

"Beyond this we have numerous opportunities to generate additional compelling clinical data with other [new molecular entities (NMEs)]," Dolsten said. He noted that Pfizer has new approaches to deal with drug resistance in estrogen receptor-positive breast cancer, including a new generation of CDK inhibitors and a triple combination containing gedatolisib. The latter is in a Phase 1b study.

In the prostate cancer area, he said Pfizer recently started clinical trials with an epigenetic agent targeting EZH2 and has a cancer vaccine with a new platform for prostate cancer. In addition, Dolsten said the company plans within the next nine to 12 months to start clinical trials with nanoparticles containing small molecules targeting resistance mechanisms in prostate cancer.

Pfizer doubled down in oncology investment under the leadership of CEO Ian Read and gained some credibility with the launch of Xalkori, but it was the launch of Ibrance in 2015 that gave Pfizer a powerful revenue generator in oncology. Ibrance accounted for more than half of Pfizer's oncology sales in 2017 and has grown into one of Pfizer's top three brands behind the Prevnar 13 pneumococcal vaccine and the pain drug Lyrica (pregabalin). It was one of the most commercially successful oncology launches over the last 12 years. (Also see "The Most Successful Oncology Launches Of A Decade" - Scrip, 28 Feb, 2018.).

The renal cancer drug Sutent(sunitinib) is another blockbuster, as is Xtandi, which Pfizer gained with its $14bn acquisition of Medivation Inc.in 2016, though Pfizer shares profits and revenue with Astellas Pharma Inc.in the US and receives royalties on sales outside the US. 

The company's third anchor oncology drug is the PD-L1 inhibitor Bavencio, which is approved for Merkel cell carcinoma and bladder cancer. Pfizer and Merck split profits generated by Bavencio under their collaboration, though the companies have struggled to get their footing in the competitive anti-PD-1/PD-L1 market behind the early leadersBristol-Myers Squibb Co.and Merck & Co. Inc.

Pfizer On Its Decision To Out-License CAR-T

Pfizer is interested in immuno-oncology beyond its focus on immune checkpoints, including chimeric antigen T cell receptor (CAR-T) therapies, vaccines and small molecule combinations. But the company recently outsourced its CAR-T programs to former Kite Pharma Inc. executives, who formed the start-up Allogene Therapeutics Inc. with Pfizer's research team. (Also see "'We Jumped' At Opportunity To Take On Pfizer's CAR-T Program, Allogene's Chang Says" - Scrip, 4 Apr, 2018.)

Pfizer's Robert Abraham, senior VP and group head of oncology R&D, who attended the press briefing by phone, explained the company's decision to create the company with the Kite group. He noted that Pfizer had done considerable work with the allogeneic CAR-T platform, which it acquired and developed in collaboration with Cellectis SA, and recognized that there were obstacles going forward. 

"We felt that the CAR-T platform, the development of this platform and the transition into solid tumors, would best be handled by a group that had one mission, that is to make CAR-T a viable therapy for solid tumors," he said.

Abraham said that breaching the solid tumor barrier is going to present challenges that largely have not been encountered in the hematologic malignancy space. He said the engineered T-cells will encounter a very immunosuppressive space and that the dominant immunosuppressive factors have to be identified. Another important challenge, he said, is the paucity of solid tumor antigens.

"In order to have a safe CAR-T cell, one needs to identify antigens that are selectively expressed or highly over-expressed on tumor cells relative to normal cells in the body to generate a sufficient therapeutic index to have an effective therapy," Abraham said.

With experienced leadership at companies like Allogene, "I think we'll see over the next five to 10 years a very good chance that CAR-Ts will enter into the solid tumor space in a big way," he added.