Conference Coverage

Back to the drawing board for MPN combo



NEWPORT BEACH, CALIF. – The combination of ruxolitinib and decitabine will not proceed to a phase 3 trial in patients with accelerated or blast phase myeloproliferative neoplasms (MPNs).

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The combination demonstrated activity and tolerability in a phase 2 trial, but outcomes were not optimal, according to Raajit K. Rampal, MD, PhD, of Memorial Sloan Kettering Cancer Center in New York.

“[P]erhaps the outcomes might be favorable compared to standard induction chemotherapy regimens,” Dr. Rampal said. “Nonetheless, it’s clear that we still have a lot of work to do, and the outcomes are not optimal in these patients.”

However, Dr. Rampal and his colleagues are investigating the possibility of combining ruxolitinib and decitabine with other agents to treat patients with accelerated or blast phase MPNs.

Dr. Rampal and his colleagues presented results from the phase 2 trial in a poster at the Acute Leukemia Forum of Hemedicus.

The trial (NCT02076191) enrolled 25 patients, 10 with accelerated phase MPN (10%-19% blasts) and 15 with blast phase MPN (at least 20% blasts). The patients’ median age was 71 years.

Patients had a median disease duration of 72.9 months. Six patients (25%) had received prior ruxolitinib, and two (8.3%) had received prior decitabine.

Treatment and safety

For the first cycle, patients received decitabine at 20 mg/m2 per day on days 8-12 and ruxolitinib at 25 mg twice a day on days 1-35. For subsequent cycles, patients received the same dose of decitabine on days 1-5 and ruxolitinib at 10 mg twice a day on days 6-28. Patients were treated until progression, withdrawal, or unacceptable toxicity.

“The adverse events we saw in this study were typical for this population, including fevers, mostly neutropenic fevers, as well as anemia and thrombocytopenia,” Dr. Rampal said.

Nonhematologic adverse events (AEs) included fatigue, abdominal pain, pneumonia, diarrhea, dizziness, and constipation. Hematologic AEs included anemia, neutropenia, febrile neutropenia, and thrombocytopenia.

Response and survival

Eighteen patients were evaluable for response. Four patients were not evaluable because they withdrew from the study due to secondary AEs and completed one cycle of therapy or less, two patients did not have circulating blasts at baseline, and one patient refused further treatment.

Among the evaluable patients, nine (50%) achieved a partial response, including four patients with accelerated phase MPN and five with blast phase MPN.

Two patients (11.1%), one with accelerated phase MPN and one with blast phase MPN, achieved a complete response with incomplete count recovery.

The remaining seven patients (38.9%), five with blast phase MPN and two with accelerated phase MPN, did not respond.

The median overall survival was 7.6 months for the entire cohort, 9.7 months for patients with blast phase MPN, and 5.8 months for patients with accelerated phase MPN.

Based on these results, Dr. Rampal and his colleagues theorized that ruxolitinib plus decitabine might be improved by the addition of other agents. The researchers are currently investigating this possibility.

“The work for this trial really came out of preclinical work in the laboratory where we combined these drugs and saw efficacy in murine models,” Dr. Rampal said. “So we’re going back to the drawing board and looking at those again to see, ‘Can we come up with new rational combinations?’ ”

Dr. Rampal and his colleagues reported having no conflicts of interest. Their study was supported by the National Institutes of Health, the National Cancer Institute, and Incyte Corporation.

The Acute Leukemia Forum is held by Hemedicus, which is owned by the same company as this news organization.

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