RATIONALE: Thalidomide may stop the growth of systemic mastocytosis by blocking blood flow to the disease.

PURPOSE: This phase II trial is studying how well thalidomide works in treating patients with relapsed or progressive systemic mastocytosis.

OBJECTIVES:

Primary

• Determine the objective response rate at 6 months in patients with systemic mastocytosis treated with thalidomide.

Secondary

• Determine the tolerability of this drug in these patients.

OUTLINE: This is a multicenter study.

Patients receive oral thalidomide once daily for 6 months in the absence of disease progression.

DISEASE CHARACTERISTICS:

• Diagnosis of systemic mastocytosis

  • Aggressive or borderline (smoldering) disease (in first line or more)
  • Relapsed or progressive disease

• Measurable or evaluable disease

• Presence of c-Kit D816V mutation in the skin, spine, or infiltrated organs

• No nonsymptomatic mastocytosis

PATIENT CHARACTERISTICS:

• Life expectancy > 3 months
• Not pregnant or nursing
• Negative pregnancy test
• Fertile patients must use effective contraception for 1 month prior to, during, and until first menstrual cycle after completion of study treatment
• Bilirubin < 2 times normal (unrelated to disease)
• Liver enzymes < 2 times normal (unrelated to disease)
• Creatinine ≤ 300 mmol/L
• No central or peripheral neuropathy leading to psychiatric concerns
• No HIV positivity
• No active infection or other serious underlying illness that would preclude treatment
• No history of thromboembolism or deep vein thrombosis
• No geographical, social, or psychological reasons preventing medical monitoring

PRIOR CONCURRENT THERAPY:

• More than 4 weeks since prior antitumor therapy (e.g., chemotherapy, radiotherapy)
• No other concurrent treatment specific for this disease
• No concurrent participation in another experimental drug trial