Posted on behalf of Hannah Waters

Finally June has arrived, bringing with it heat, tank tops, pool parties — and the annual meeting of the American Society of Clinical Oncology (ASCO), when tens of thousands of doctors and scientists gather in Chicago to hear and discuss recent clinical findings in cancer treatment. Over the past week, cancer researchers presented more than 4,000 abstracts, but a pair of them in particular stood out: results from phase 3 clinical trials of two drugs for the treatment of an aggressive form of skin cancer known as metastatic melanoma.

Once melanoma spreads throughout the body, it can be incredibly difficult to treat or cure. Until this year, the only drug approved in the US to treat metastatic melanoma was the chemotherapeutic agent dacarbazine, but this drug’s impact has been underwhelming: with a standard dose of treatment, patients survive an average of just six to eight months. So, cancer researchers have been clamoring to develop better drugs

At ASCO, researchers presented results from clinical trials of two new drugs, each taken in combination with dacarbazine, that promise to drastically increase life expectancy further. One of these new drugs targets a mutated form of the BRAF oncoprotein that is found in around half of all people with metastatic melanoma, while the other blocks a key negative regulator of immune system activation.

In research presented at the conference and published concurrently in the New England Journal of Medicine, a team led by Paul Chapman of the Memorial Sloan-Kettering Cancer Center in New York tested a Roche/Genentech BRAF inhibitor called vemurafenib in 675 patients with late stage melanoma. Remarkably, combined treatment with vemurafenib and chemotherapy showed a 63% decrease in the risk of death and 74% decrease in the risk of cancer return compared to chemotherapy alone — a high enough difference that earlier this year the phase 3 trial was halted prematurely so study subjects could switch from the control group to take vemurafenib (see ‘Companies compete over mutation-specific melanoma drugs’).

The second study, also published in the same issue of NEJM, investigated Bristol-Myers Squibb’s antibody therapy Yervoy (ipilimumab), which the US Food and Drug Administration approved in March for treating metastatic melanoma. Researchers had previously shown that the drug, which boosts the body’s immune response by blocking a repressor of T-cell activation, extended average life span by nearly four months more than an experimental vaccine. And at the Chicago meeting, medical oncologist Jedd Wolchok, also at Sloan-Kettering, presented additional data from a 502-person trial showing that Yervoy in combination with chemotherapy increased lifespan by two months longer than chemo alone.

Overall, it’s been a big weekend for melanoma treatment, although I still have one question left: What would happen if you combined all three drugs?