Pfizer (NYSE:PFE) ranks as the biggest drugmaker in the world in terms of prescription drug sales. But the company hasn't really been at the forefront in one of the most lucrative therapeutic areas of the biopharmaceutical industry -- oncology.

Andy Schmeltz, Pfizer's global president of oncology, and Chris Boshoff, the company's head and senior vice president for immuno-oncology, laid out Pfizer's oncology strategy at the Cowen healthcare conference on Wednesday. Schmeltz and Boshoff weren't able to attend the conference due to weather conditions in the northeastern U.S., but the Pfizer executives presented and fielded questions remotely.

One of Schmeltz's first slides referred to Pfizer's mindset just a few years ago as "opportunistic and niche" when it came to development of cancer drugs. However, he said the company is on the path to become a leader in the space. Here are five drugs Pfizer thinks are key to moving into the big leagues for cancer treatment.

Pill opened with boxing glove extended punching cancer cell

Image source: Getty Images.

1. Ibrance

Ibrance is Pfizer's biggest oncology star right now. The breast cancer drug generated sales of $3.1 billion in 2017, up 46% year over year. Market research firm EvaluatePharma projects that Ibrance will become one of the five best-selling cancer drugs in the world by 2022, with sales of more than $7 billion.

But Ibrance has two rivals on the market now that are also CDK 4/6 inhibitors. Novartis (NYSE:NVS) won FDA approval for Kisquali in March 2017, while Eli Lilly (NYSE:LLY) gained approval for Verzenio in September. Could these two drugs derail Ibrance? Andy Schmeltz doesn't think so.

Schmeltz said Ibrance enjoys more than just a first-mover advantage. He believes the strength of the clinical data and the compelling benefit/risk profile for Ibrance should keep the drug on top. The presence of additional CDK 4/6 inhibitors is likely to expand the market, according to Schmeltz, with Ibrance taking "a disproportionate share" of the increase. 

Lilly thinks Verzenio holds promise in treating other types of cancer, but Novartis isn't so optimistic about the potential in moving beyond breast cancer for Kisquali. Chris Boshoff indicated that Pfizer lines up more with Lilly on the opportunity for a CDK 4/6 inhibitor to treat other tumor types, noting that the company has many studies in progress evaluating Ibrance in treating various solid tumors.

2. Xtandi

Pfizer picked up Xtandi with its 2016 acquisition of Medivation. The prostate cancer drug made $590 million in 2017, but Schmeltz said the potential market opportunity for Xtandi is much larger.

Based on solid data from its late-stage Prosper clinical study, Pfizer filed for U.S. and European approval of an additional indication in treating non-metastatic prostate cancer. Schmeltz said Pfizer expects to get confirmation of the filing from the FDA soon. He thinks approval for the non-metastatic prostate cancer indication could double the opportunity for Xtandi, which currently is approved for treating metastatic prostate cancer.

3. Bavencio

When it comes to immuno-oncology (IO), Schmeltz acknowledged that Pfizer hasn't been "a leading player, to say the least, in the first wave" of IO drugs. However, Pfizer partnered with German-based Merck Serono (not to be confused with the U.S. drugmaker Merck) on Bavencio. The PD-L1 inhibitor won approval last year for treating two indications: Merkel cell carcinoma (MCC) and bladder cancer.

Schmeltz said Pfizer "remains committed" to its partnership with Merck Serono on Bavencio but admitted that MCC and bladder cancer are "niche spaces." However, he stated that the next wave of combination therapies featuring Bavencio holds promise. Pfizer believes the future of cancer treatment lies in combo therapies, with IO drugs as one of the anchors of these combinations. Schmeltz added that Pfizer is also exploring other IO combos beyond its partnership with Merck Serono.

4. Lorlatinib

Pfizer likes the opportunities for lorlatinib. An FDA approval decision for the drug in treating ALK-positive metastatic non-small cell lung cancer (NSCLC) is expected by August 2018.

Schmeltz sees lorlatinib as a "potential best-in-class ALK inhibitor" that "fills a void in the space." Several ALK inhibitors have already been approved for treating NSCLC, including Pfizer's own Xalkori. However, lorlatinib should be able to overcome resistance of tumors to Xalkori and some other ALK inhibitors that result from mutations in cancer cells. 

5. Talazoparib

Talazoparib ranks as one of the most promising candidates in Pfizer's oncology pipeline. In December, the company reported positive results from a late-stage study evaluating the PARP inhibitor in treating metastatic breast cancer.

Boshoff stated that Pfizer is "excited about this medicine," referring to talazoparib. He said that in pre-clinical studies, the drug stood out as "the most potent PARP inhibitor." Schmeltz said talazoparib could have a differentiated profile from other drugs with its dual mechanism of action that blocks PARP enzyme activity and traps PARP on the sites of DNA damage. 

Others on the roster

Pfizer also has other cancer drugs either on the market or in its pipeline that Schmeltz and Boshoff didn't talk about much at the Cowen conference. New drug dacomitinib awaits regulatory approval. Pfizer also hopes to win approvals for new indications for Bosulif and Sutent. In addition, Pfizer's early-stage pipeline is chock full of promising drugs, notably including CAR-T therapy UCART19.

Schmeltz pointed out that in 2010, Pfizer had only two approved cancer drugs treating three indications. That number has increased to 10 approved cancer drugs treating 17 indications. By 2020, Pfizer hopes to have 14 approved cancer drugs targeting 28 indications. If it's successful in achieving this goal, Pfizer just might make it to the big leagues of cancer treatment.

Keith Speights owns shares of Pfizer. The Motley Fool has no position in any of the stocks mentioned. The Motley Fool has a disclosure policy.