CAR-T therapy has been getting a lot of attention from drugmakers, investors and clinicians in recent years, but there’s also a battle raging between it and another form of therapy going for the same targets.

At the recently concluded annual meeting of the American Society of Clinical Oncology (ASCO) a group of researchers from Mexico City described a surprising discovery: In a phase 2 trial in patients with stage 4 lung cancer, a 24-year-old diabetes drug significantly improved survival when added to a standard therapy. That drug, metformin, is used to lower blood sugar in type 2 diabetics. 

Each year, the ASCO annual meeting serves as a forum for some of the most important clinical studies in oncology, giving physicians important insights into how best to treat patients with cancer. But the results are not always clear cut, particularly in the rapidly advancing field of immunotherapy. Below are three pressing questions researchers are still grappling to answer:

Tens of thousands attendees flooded the cavernous halls of Chicago's McCormick Place this weekend for the 54th Annual Meeting of the American Society of Clinical Oncology. The industry is buzzing about new data from the mountain of abstracts presented and potential implications for treating cancer.

AbbVie $ABBV has managed to convince at least one prominent analyst that Rova-T is absolutely worthless, as the company’s vision of a $5 billion earner gradually dissolves.

Bristol-Myers Squibb’s new strategy In lung cancer relies on showing its new biomarker can help predict who benefits most from immunotherapy combinations. And Monday at the American Society of Clinical Oncology annual meeting, it rolled out data to support that notion.

At last year’s ASCO, IDO inhibitors were being hailed as the next big thing in cancer immunotherapy, but a series of trial setbacks took that optimism down a notch. Now, armed with new data on its lead IDO drug indoximod, NewLink Genetics insists there is still hope for the class.

Jounce Therapeutics' stock fell to a 52-week low Monday as shaky efficacy data from a Phase 1/2 trial of the biotech's lead drug weighed on the company's share price. 

After unveiling positive results for its lead drug, sacituzumab govitecan, in breast cancer at the influential American Society of Clinical Oncology (ASCO) conference, shares in Immunomedics(NASDAQ:IMMU) rallied by as much as 14.7% today before settling in for a gain of 9.3% at 3 p.m. EDT.

After reporting solid safety results for umbralisib as a monotherapy in chronic lymphocytic leukemia (CLL) patients who are intolerant to prior BTK (Imbruvica) or PI3K delta inhibitor (Zydelig) therapy, TG Therapeutics (NASDAQ:TGTX) 10.8% on Monday.