It may be premature to rely on polymerase chain reaction-based monitoring as the sole criteria for treatment decisions in certain individuals with polycythemia vera (PV), according to an analysis involving 106 PV patients treated with recombinant interferon (rIFN).

Investigators identified 15 participants who had at least 2 bone marrow examinations with paired JAK2V617F allelic burden testing. Median allele burden was 62% at initial biopsy, and decreased to 33% at subsequent biopsy. Patients were initially treated with peg-rIFNα-2a (n=13) or rIFNα-2b (n=2). Among the results:

• All patients achieved either a complete (n=8) or a partial (n=7) hematologic response.
• Regarding molecular response, 3 achieved complete, 4 partial, and 8 no response.
• No significant correlations were seen between change in JAK2V617F allelic burden and cellularity and fibrosis.
• There was no correlation between JAK2V617F allelic burden and presence of p-STAT5 staining.

The authors concluded that inappropriate discontinuation of rIFNα therapy due to PCR-based monitoring may prematurely annul its value.