Mutations of members of the ras family are among the most common oncogene mutations found in multiple myeloma (MM). We have examined the mutational status of the N- and K-ras genes at codons 12, 13, and 61 in 160 newly diagnosed MM patients enrolled on the Eastern Cooperative Oncology Group (ECOG) phase III clinical trial E9486. The total incidence of ras mutations was found to be 39% of the samples analyzed. Five patients showed evidence of more than one mutation. We obtained 22 marrow samples from patients at the time of disease progression or relapse, for whom a ras mutation was identified at diagnosis. In all cases, the ras mutation of the disease progression sample was identical to that found at diagnosis. In contrast, three of 25 patients who did not show any ras mutation at diagnosis acquired a ras mutation at the time of disease progression. No significant association was observed between any ras mutation and stage of disease, beta 2-microglobulin levels, labelling index, or protein type. The mean tumor burden and median survival for patients with mutations of N-ras was indistinguishable from patients with no ras mutations. However, patients with K-ras mutations had a significantly higher mean bone marrow tumor burden at diagnosis than patients with no ras mutations (57% v 36%, P ‼ .02); and the median survival of patients with a K-ras mutation was significantly shorter (2.0 v 3.7 years, P ‼ .02). To determine if the status of ras mutations could affect treatment response, we examined patient survival on the three treatment arms of E9486. Although the presence of a ras mutation in the multidrug treatment, VBMCP alone, showed a marginal significance, neither the VBMCP, nor the addition of interferon-alpha showed statistically significant survival differences between mutant and wildtype ras status. Interestingly, there appeared to be a statistically significant difference in survival of patients treated with VBMCP and alternating high doses of cyclophosphamide + prednisone. Patients with ras mutations had a median survival of 2.1 years; patients with wild-type ras had a median survival of 4.0 years (P ‼ .01).

One of the distinguishing features of multiple myeloma (MM) is the proliferation of plasma cells that home to the bone marrow (BM). However, there still remains some uncertainty concerning the presence of related malignant cells in the peripheral blood of myeloma patients. Using consensus oligonucleotide primers, we amplified the third complementary determining region (CDR3) of rearranged immunoglobulin heavy chain alleles from MM marrow samples by polymerase chain reaction (PCR). From the sequences of the products, we derived allele-specific oligonucleotides (ASO), and these were used in subsequent amplification reactions to detect malignant clones in the peripheral blood of myeloma patients. This method is highly specific and sensitive to 1 malignant cell in the background of 10(5) normal cells. Using this method we detected circulating malignant cells in 13 of 14 previously untreated MM patients. Furthermore, by applying ASO-PCR to artificial titrations of initial BM DNA sample into normal peripheral blood lymphocyte (PBL) DNA we were able to generate standard curves and quantitate the amount of tumor in the patient PBL. We observed a wide variation in the amount of circulating tumor between patients. In addition, we found that the incidence of circulating tumor cells was independent of BM tumor burden and stage of disease. The detection and quantitation of circulating tumor cells in the PBL of MM patients may offer an alternative assessment of the disease and may be an important consideration in the use of peripheral stem cells in bone marrow transplantation.

No abstract

One of the distinguishing features of multiple myeloma (MM) is the proliferation of plasma cells that home to the bone marrow (BM). However, there still remains some uncertainty concerning the presence of related malignant cells in the peripheral blood of myeloma patients. Using consensus oligonucleotide primers, we amplified the third complementary determining region (CDR3) of rearranged immunoglobulin heavy chain alleles from MM marrow samples by polymerase chain reaction (PCR). From the sequences of the products, we derived allele-specific oligonucleotides (ASO), and these were used in subsequent amplification reactions to detect malignant clones in the peripheral blood of myeloma patients. This method is highly specific and sensitive to 1 malignant cell in the background of 10(5) normal cells. Using this method we detected circulating malignant cells in 13 of 14 previously untreated MM patients. Furthermore, by applying ASO-PCR to artificial titrations of initial BM DNA sample into normal peripheral blood lymphocyte (PBL) DNA we were able to generate standard curves and quantitate the amount of tumor in the patient PBL. We observed a wide variation in the amount of circulating tumor between patients. In addition, we found that the incidence of circulating tumor cells was independent of BM tumor burden and stage of disease. The detection and quantitation of circulating tumor cells in the PBL of MM patients may offer an alternative assessment of the disease and may be an important consideration in the use of peripheral stem cells in bone marrow transplantation.

The junctional sequences corresponding to the complementarity determining region 3 (CDR3) of rearranged heavy chain Ig genes can provide allele-specific markers in the detection of B-lymphoid malignancies. Consensus oligonucleotide primers were used to amplify CDR3 regions of rearranged heavy chain alleles in clinical samples from myeloma, acute lymphocytic leukemia, and chronic lymphocytic leukemia patients. From the sequence of the amplified products, allele-specific primers were synthesized and used directly in polymerase chain reaction (PCR) amplification to detect the malignant clone. This method was both highly specific and sensitive to 1 malignant B-cell in a background of 10(5) normal cells. In addition, parameters that affect the linearity of PCR detection were determined and, by using titrations of malignant target cells to generate standard curves, quantitations of residual malignancies were determined. The application of this method is shown in an analysis of myeloma patients whose marrows were analyzed sequentially during therapy. Allele-specific oligonucleotide-PCR provided a rapid, highly specific and quantitative measure of residual disease, even in patients with clinical parameters indicating complete remission.

The Eastern Cooperative Oncology Group (ECOG) conducted a prospective phase III study in patients with relapsed/refractory acute myeloid leukemia (AML) to evaluate whether administration of repeated courses of low-dose cytarabine (LDAC) maintenance therapy after induction of complete remission in advanced AML would improve disease-free and overall survival. Patients with AML in second/later relapse or refractory disease were first treated with a combination of high-dose cytarabine and amsacrine. Those who achieved complete remission were then randomized to observation or to receive LDAC, 10 mg/m 2 subcutaneously twice a day ؋2 21 days every 2 months until relapse occurred. Of 86 patients eligible for randomization, 41 patients were assigned to receive LDAC and 45 patients to observation. The median disease-free survival was 7.4 months for patients assigned to LDAC compared to 3.3 months for patients receiving no additional therapy, P = 0.084. The median survival from randomization was 10.9 months and 7.0 months for patients receiving LDAC maintenance chemotherapy and observation, respectively (P = 0.615). The data from this study suggest that LDAC maintenance therapy given to patients with advanced AML who achieve complete remission can increase disease-free survival compared to observation, but does not improve overall survival. Nevertheless, because of the ineffectiveness and toxicity of intensive post-remission chemotherapy in this circumstance, LDAC maintenance therapy, a tolerable outpatient regimen, offers the potential for improved quality of life. Leukemia (2000) 14, 1349-1353.

The prognosis for patients with acute myeloid leukemia in first relapse is generally poor. The ability to induce a second complete remission (CR) with the same chemotherapy used in initial induction therapy is limited. Remission inversion rate, defined as achieving a longer second CR than the first CR in response to standard chemotherapy for relapse, is important in assessing studies of novel chemotherapy or immunologic treatment strategies for patients with relapsed disease. One hundred and twenty-four patients entered on two Eastern Cooperative Oncology Group (ECOG) studies for patients with relapsed AML were analyzed to determine the remission inversion rate. Twenty-two of the 124 patients (18%; 95% confidence interval 12-26%) experienced a longer second CR duration than the first CR duration by at least 2 months. Inversion of CR duration is thus not a rare event. The inversion frequency reported here establishes a baseline upon which future studies in relapsed disease need to be defined.

The junctional sequences corresponding to the complementarity determining region 3 (CDR3) of rearranged heavy chain Ig genes can provide allele-specific markers in the detection of B-lymphoid malignancies. Consensus oligonucleotide primers were used to amplify CDR3 regions of rearranged heavy chain alleles in clinical samples from myeloma, acute lymphocytic leukemia, and chronic lymphocytic leukemia patients. From the sequence of the amplified products, allele-specific primers were synthesized and used directly in polymerase chain reaction (PCR) amplification to detect the malignant clone. This method was both highly specific and sensitive to 1 malignant B-cell in a background of 10(5) normal cells. In addition, parameters that affect the linearity of PCR detection were determined and, by using titrations of malignant target cells to generate standard curves, quantitations of residual malignancies were determined. The application of this method is shown in an analysis of myeloma patients whose marrows were analyzed sequentially during therapy. Allele-specific oligonucleotide-PCR provided a rapid, highly specific and quantitative measure of residual disease, even in patients with clinical parameters indicating complete remission.