'Game-Changing' New Drug Can 'Melt Away' Blood Cancer

High-power magnification (1000x) of a blood smear showing chronic lymphocytic leukemia. Mary Ann Thompson/Wikimedia

A "game-changing" new cancer drug developed by Australian researchers has dramatically improved the odds of survival for patients with two types of blood cancer, according to the results of two new trials published in the New England Journal of Medicine.

The drug, known as venetoclax, could replace chemotherapy and change the way physicians treat blood cancers, according to lead researcher on one of the trials, John Seymour from the Peter MacCallum Cancer Centre (PMCC) in Victoria, Australia.

In this large-scale trial, 389 patients across 20 countries with chronic lymphocytic leukaemia (CLL) who had previously been treated and relapsed were either given venetoclax in combination with a standard immunotherapy drug known as rituximab, or rituximab on its own. CLL is currently untreatable when a patient relapses.

But after two years, nearly 85% of patients in the trial who were given venetoclax in combination with rituximab had very few or almost no detectable leukaemia cancer cells, compared to just 36% of those who received the standard immunotherapy drug on its own.

"That venetoclax is able to produce such dramatic results in this hard-to-treat patient group is remarkable and has led to much excitement among blood cancer clinicians globally and the research community particularly in Melbourne where this drug was pioneered," Seymour said in a statement.

"The data shows venetoclax should replace chemotherapy altogether in patients with advanced forms of CLL—a practice-changing result which will rapidly translate into the standard of care globally."

In the second trial, led by Constantine Tam, also from PMCC, venetoclax was combined with the immunotherapy drug ibrutinib and given to 24 Mantle Cell lymphoma (MCL) patients who had also previously been treated and relapsed.

Like CLL, MCL is also incurable after relapse but is much rarer and more aggressive, Sunil Iyengar, a consultant haemato-oncologist at the Royal Marsden NHS Foundation Trust in the U.K, who was not involved in the studies, told Newsweek.

The results of this study showed that 78% of patients were cancer free for at least 15 months after treatment.

Iyengar said the results of both studies were "exciting". "It's unprecedented that we're seeing such deep responses in a such a high proportion of patients. These drugs will almost certainly replace chemotherapy going forward. It could be game-changing if these responses are durable."

However, Iyengar did note that the follow up times on both studies were relatively short so more longer-term studies should be carried out to see if the cancer returns further down the line.

Venetoclax was developed based on a landmark discovery made in Melbourne in the late 1980s by scientists at the Walter and Eliza Hall Institute. They found that a protein called BCL-2 promoted the survival of cancer cells.

"Venetoclax selectively targets BCL-2, essentially causing cancerous cells to simply melt away, in many instances," Andrew Roberts a clinical haematologist at Peter Mac and researcher at Walter and Eliza Hall, and author of the second trial, said in a statement.