Pfizer’s second-line breast-cancer therapy Ibrance generated $38 million in US sales since its February launch, beating analysts’ expectations and reinforcing the drugmaker’s strategy to make the drug the new standard of care for these patients.  

So far about 800 physicians have prescribed the drug to treat 2,000 patients after the FDA granted Ibrance accelerated approval to treat some patients with metastatic breast cancer. Previous analyst estimates said the drug would bring in about $150 million this year, with peak sales reaching $3.8 billion by 2020.

“The first-line market share is already approaching 10%,” Albert Bourla, group president of Pfizer vaccines, oncology and consumer healthcare, told investors. “That’s way ahead of previous outlooks and we also see strong reimbursement so far.”

Bourla went on to say that Pfizer expects Ibrance to eventually become the new standard of care in first-line breast-cancer patients. Earlier this month the company announced that a Phase-III trial of the drug in patients with recurrent breast cancer was stopped early after the drug showed it delayed disease progression, and the company plans to present results from that trial at the American Society of Clinical Oncology’s annual meeting, which starts next month.

Ibrance is also being tested in 30 studies for indications beyond breast cancer, including head-and-neck cancer and melanoma.

Prevnar 13 was another driver in first-quarter performance for Pfizer. Sales of the pneumonia vaccine grew 41% to $1.3 billion in the first quarter of 2015, compared to $927 million in the same quarter in 2014. Pfizer CEO Ian Read primarily attributed the growth to recommendations made in September by the Centers for Disease Control and Prevention. About 47 million American adults who are 65 years old or older are now eligible to receive the vaccination. As of December, the vaccine is covered by Medicare.  

“We believe our efforts are increasing the sense of urgency to vaccinate and driving consumers to request the Prevnar vaccine,” Read said during a call with investors.

Pfizer’s profit rose 2% to $2.4 billion in the first quarter of the year, compared to $2.33 billion in the same quarter a year ago. But overall revenue fell 4% to $10.8 billion in the fourth quarter, due to the stronger dollar, Pfizer said.

Read also said the company’s $17-billion acquisition of Hospira is expected to close in the second half of the year.