What happened

Shares of MacroGenics (NASDAQ:MGNX) surged today, ahead of the May 13 release of abstracts of presentations scheduled for the American Society of Clinical Oncology meeting at the end of the month. Investor optimism that the abstracts will reveal promising data for the company's early-stage drugs sent shares soaring 29.4% by the close on Monday.

So what

Margetuximab, an optimized formulation of the top-selling breast cancer drug Herceptin, is the biotech's most advanced drug. Last week, news that a Food and Drug Administration decision on margetuximab could happen by the end of 2020 sparked a one-day rally of over 200%. Today, the company's earlier-stage drug candidates, MGD013 and MGC018, are fueling optimism.

A person drawing an uptrending arrow on paper.

Image source: Getty Images.

MGD013 is an anti-Lag3 & PD-1 bispecific monoclonal antibody being evaluated in phase 1 trials in the treatment of metastatic breast cancer. At ASCO, researchers are expected to discuss a 40% overall response rate in HER2+ solid-tumor patients receiving a combination therapy of MGD013 and margetuximab.

Researchers are also expected to share insight into an MGC018 phase 1 trial in prostate cancer patients. Last week, MacroGenics said the anti-B7-H3 antibody drug conjugate reduced prostate-specific antigen, or PSA, by over 50% in five of seven patients with metastatic castration-resistant prostate cancer.

Now what

If there aren't any surprises in the abstracts, it could bolster the argument that MacroGenics is building out a multidrug platform of potential blockbuster medications. 

The company expects to report final data for overall survival for its phase 3 SOPHIA study of margetuximab in HER2-positive metastatic breast cancer later this year. It also thinks it has a shot at receiving an FDA decision for the drug as soon as December. If approved, it could become a top-selling alternative to Herceptin, which had sales of over $6 billion in 2019 despite having already lost patent protection. Previously, margetuximab outpeformed Herceptin, producing a progression-free survival rate of 5.8 months versus 4.9 months for Herceptin. 

If magetuximab wins an OK and MGD013 combination therapy is effective, it could help the company reshape breast cancer treatment someday. Positive MGC018 data would similarly be good news because prostate cancer treatment is a multibillion-dollar market. Given the importance of the data in these upcoming abstracts, MacroGenics could be in store for more volatility this week, so only the most aggressive investors ought to consider buying it.