Abstract 6752: Patient (pt) characteristics, diagnostic journey, and cancer enrichment among pts with nonspecific signs and/or symptoms (s/sx) in the US community oncology setting: a real-world retrospective study

Of the >1.6 million people diagnosed with cancer in the US each year, >60% are diagnosed after symptomatic presentation, including nonspecific s/sx. These nonspecific s/sx may cause pts to undergo unnecessary diagnostic evaluation while the possibility of cancer and search for its origin is explored, causing delayed treatment and poor outcomes. Additionally, pts who do not have cancer are often subjected to various undirected/misdirected procedures due to initial cancer suspicion. Our objective was to examine pt characteristics, diagnostic journey, and cancer incidence of pts with nonspecific s/sx within The US Oncology Network.

This retrospective observational cohort study included pts aged ≥40 with ≥1 of the following nonspecific s/sx in their problem list at their first visit within The US Oncology Network (index date) during the identification period from 1/1/2016 to 12/31/2020: anemia, venous thromboembolism, general malaise, weight loss, nonspecific abdominal symptoms, new and unexplained breathlessness, unexplained worsening pain, and abnormal lab test results. Pts were excluded if diagnosed with any cancer (except basal cell carcinoma and squamous cell carcinoma skin cancer) within 3 years prior to or on index date. Pts were followed longitudinally with data from electronic health records for initial cancer diagnosis (dx), death, end of study observation period, or 12 months, whichever occurred first. Demographic and clinical characteristics were assessed descriptively.

103,984 pts were identified. The median age was 65.7, 64% were female, 65% were White, 41% were obese, 47% were never smokers, and 48% were from a southern practice region. 6,774/103,984 pts (7%) were diagnosed with cancer and 6,537/6,774 (97%) with 1 primary cancer: 3,825/6,537 (59%) were diagnosed with a hematologic malignancy and 2,712/6,537 (41%) with a solid tumor cancer. Among pts diagnosed with primary solid tumors, 31% had gastrointestinal, 15% genitourinary, 15% respiratory, 13% breast, and 11% gynecologic cancer. Among pts diagnosed with cancer, median time to cancer dx after being referred to secondary care within The US Oncology Network with nonspecific s/sx was >5 wks (solid: >7 wks; hematologic: >4 wks); by 17 and 34 wks, 75% and 90% of pts received a cancer dx, respectively.

Within this population of pts most frequently presenting with nonspecific hematologic s/sx and subsequent cancer dx, 40% were diagnosed with solid tumor cancers within 1 year. This speaks to the unmet need for more tools such as a multi-cancer detection test that could aid in detection of multiple cancers and faster diagnostic resolution of nonspecific s/sx. Given the impact of delayed cancer dx and timely treatment on outcomes, such a test could potentially substantially improve cancer care and diagnostic evaluations.

Citation Format: Christopher Benton, Ding He, Karen Todoroff, Marie V. Coignet, Ying Luan, Kathryn N. Kurtzman, Ira Zackon. Patient (pt) characteristics, diagnostic journey, and cancer enrichment among pts with nonspecific signs and/or symptoms (s/sx) in the US community oncology setting: a real-world retrospective study. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 6752.

MPN-077 Characteristics, Blood Counts, Treatments, and Clinical Outcomes of 3022 Patients With Polycythemia Vera (PV) Treated in US Community Practices

CONTEXT

Cytoreduction with hydroxyurea (HU) is the recommended first-line (1L) treatment for high-risk PV (age ≥60 years; history of thrombosis), but many patients have a suboptimal response.

OBJECTIVE

To describe characteristics, blood counts, treatments, and clinical outcomes among patients with PV.

DESIGN AND PATIENTS

Retrospective observational study of adults in The US Oncology Network iKnowMed electronic health record database with ≥2 post-PV diagnosis visits during the study (01JAN2008-31JAN2021).

MAIN OUTCOMES AND MEASURES

Suboptimal response was defined as meeting ≥1 of the following criteria after ≥3 months of HU treatment: (1) white blood cell (WBC) count >10×10⁹/L, (2) platelet count >400×10⁹/L, and/or (3) hematocrit (HCT) >45%. Duration of therapy and overall survival were assessed via Kaplan-Meier method.

RESULTS

Overall, 3022 patients with PV were included (mean age at diagnosis, 65.8 years [69% ≥60 years]; female, 46%; White, 85%; current/former tobacco users, 49%). At diagnosis, 7% of patients had a history of thrombosis, and 71% had high-risk PV; 37% (886/2413), 32% (778/2411), and 67% (1617/2418) had elevated WBC (>10×10⁹/L), platelets (>400×10⁹/L), and HCT (>45%), respectively. Cytoreductive therapy as 1L treatment was received by 48% of patients (44% HU); phlebotomy data were unavailable. Five-year survival probability was 84% among all patients (low-risk [age <60 years; no history of thrombosis], 97%; high-risk, 81%). Among patients who received 1L HU (n=1317), median (Q1, Q3) time from diagnosis to HU initiation was 19 (0, 189) days; median (Q1, Q3) duration of HU was 30 (9.5, 64.4) months, and 29.5 (9.5, 58.5) and 35.0 (9.5, 77.0) months for high- and low-risk patients, respectively. Among patients on 1L HU with evaluable blood counts, 55% (584/1053) had a suboptimal response (WBC >10×10⁹/L, 26%; platelets >400×10⁹/L, 26%; HCT >45%, 36%) at 3 months; similar findings were seen at 6 months. Among patients with suboptimal response to 1L HU, 5-year survival probability was 87% (low risk, 100%; high risk, 84%).

CONCLUSIONS

The prevalence of elevated blood counts at diagnosis and follow-up while on HU treatment is consistent with previous real-world experience. About 1 in 8 patients with a suboptimal response to HU died within 5 years.

Characteristics, blood counts, treatments, and clinical outcomes of 3,022 patients (Pts) with polycythemia vera (PV) treated in U.S. community practices

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Background: Cytoreduction with hydroxyurea (HU) is the recommended first-line (1L) treatment for high-risk PV (age ≥60 y or history of thrombosis), but many pts have a suboptimal response on HU. The objective of this study was to describe characteristics, blood counts, treatments, and clinical outcomes among pts with PV, including those with suboptimal response to HU, in a large network of US community oncology practices. Methods: This was a retrospective observational study of adult pts with a documented diagnosis of PV in The US Oncology Network iKnowMed electronic health record database. Pts with ≥2 post-diagnosis visits during the study observation period (01JAN2008–31JAN2021) were included in the analysis. Suboptimal response to HU was defined as meeting ≥1 of the following criteria after ≥3 months of treatment: (1) white blood cell (WBC) count > 10 × 109/L, (2) platelet count > 400 × 109/L, and/or (3) hematocrit (HCT) > 45%. Data on demographic and clinical characteristics and prior treatment were collected and summarized using descriptive statistics. Duration of therapy and overall survival were assessed via Kaplan-Meier method; pts without subsequent treatment discontinuation/death records were censored. Results: Overall, 3022 pts with PV were included in the analysis; mean age at diagnosis was 65.8 years (69% ≥60 y), 46% of pts were female, 85% were White, and 49% were current/former tobacco users. At diagnosis, 7% of pts had a history of thrombotic event, and 71% had high-risk PV; 37% (886/2413), 32% (778/2411), and 67% (1617/2418) of evaluable pts had elevated WBC (> 10 × 109/L), platelets (> 400 × 109/L), and HCT (> 45%), respectively. Nearly half of pts (48%) received a cytoreductive agent as 1L treatment (44% HU), and 52% did not receive cytoreductive therapy; phlebotomy data were unavailable. Five-year survival probability was 84% among all pts, 97% for low-risk pts (age < 60 y; no history of thrombosis), and 81% for high-risk pts. Among pts who received 1L HU (n = 1317), median (Q1, Q3) time from diagnosis to HU initiation was 19 (0, 189) days; median (Q1, Q3) duration of HU was 30 (9.5, 64.4) months overall, and 29.5 (9.5, 58.5) and 35.0 (9.5, 77.0) months for high- and low-risk pts, respectively. Among pts on 1L HU with evaluable blood counts, 55% (584/1053) had a suboptimal response (WBC > 10 × 109/L, 26%; platelets > 400 × 109/L, 26%; HCT > 45%, 36%) at 3 months; similar findings were seen at 6 months. Among pts with suboptimal response to 1L HU, 5-year survival probability was 87% overall (low risk, 100%; high risk, 84%). Conclusions: The prevalence of elevated blood counts at diagnosis and follow-up while on HU treatment is consistent with previous real-world experience. About 1 in 8 pts with a suboptimal response to HU died within 5 years. HU dose adjustments or alternative treatments may be needed for pts with suboptimal response to HU.

A Phase I/II Study of Evofosfamide, A Hypoxia-activated Prodrug with or without Bortezomib in Subjects with Relapsed/Refractory Multiple Myeloma

PURPOSE

The presence of hypoxia in the diseased bone marrow presents a new therapeutic target for multiple myeloma. Evofosfamide (formerly TH-302) is a 2-nitroimidazole prodrug of the DNA alkylator, bromo-isophosphoramide mustard, which is selectively activated under hypoxia. This trial was designed as a phase I/II study investigating evofosfamide in combination with dexamethasone, and in combination with bortezomib and dexamethasone in relapsed/refractory multiple myeloma.

PATIENTS AND METHODS

Fifty-nine patients initiated therapy, 31 received the combination of evofosfamide and dexamethasone, and 28 received the combination of evofosfamide, bortezomib, and dexamethasone. Patients were heavily pretreated with a median number of prior therapies of 7 (range: 2-15). All had previously received bortezomib and immunomodulators. The MTD, treatment toxicity, and efficacy were determined.

RESULTS

The MTD was established at 340 mg/m² evofosfamide + dexamethasone with dose-limiting mucositis at higher doses. For the combination of evofosfamide, bortezomib, and dexamethasone, no patient had a dose-limiting toxicity (DLT) and the recommended phase II dose was established at 340 mg/m². The most common ≥grade 3 adverse events (AE) were thrombocytopenia (25 patients), anemia (24 patients), neutropenia (15 patients), and leukopenia (9 patients). Skin toxicity was reported in 42 (71%) patients. Responses included 1 very good partial response (VGPR), 3 partial response (PR), 2 minor response (MR), 20 stable disease (SD), and 4 progressive disease (PD) for evofosfamide + dexamethasone and 1 complete response (CR), 2 PR, 1 MR, 18 SD, and 5 PD for evofosfamide + bortezomib + dexamethasone. Disease stabilization was observed in over 80% and this was reflective of the prolonged overall survival of 11.2 months.

CONCLUSIONS

Evofosfamide can be administered at 340 mg/m² twice a week with or without bortezomib. Clinical activity has been noted in patients with heavily pretreated relapsed refractory multiple myeloma.

Adenovirus-mediated tissue-targeted expression of the HSVtk gene for the treatment of breast cancer

In an effort to develop a genetic therapy for the treatment of breast cancer, we constructed adenoviral vectors containing either the beta-galactosidase (beta-gal) reporter gene or the herpes simplex thymidine kinase (HSVtk) suicide gene driven by breast tissue-specific promoters. We utilized upstream regulatory sequences from either the human alpha-lactalbumin (hALA) gene, or the ovine beta-lactoglobulin (oBLG) gene in these vector constructs to target expression of heterologous genes transcriptionally to breast cancer cells both in vitro and in vivo. Data derived from breast tissue-specific reporter vectors in vitro demonstrate that expression from the hALA and oBLG promoters are indeed specific for breast cells (T47D, MCF-7, ZR75-1) when compared with non-breast cells (U2OS, HeLa). Moreover, these vectors displayed tumor cell specificity when compared with the normal MCF-10A breast cell line. These vectors also displayed breast tissue specificity when injected systemically (i.v.) into lactating Balb/c mice, which suggests that these promoters maintain their tissue-specific expression pattern within the context of the adenoviral genome in vivo. Tumors, derived from T47D human breast cancer cells, were established in nude mice and injected with either the tissue-specific reporter or suicide vectors. Results from tumors injected (i.t.) with reporter adenoviruses demonstrate that these promoters are active in T47D cells when grown as established tumors and we observed a marked regression of tumors injected with suicide vectors and treated systemically with gancyclovir (150 mg/kg/day) when compared with control animals. Moreover, mouse survival was prolonged after 35 days in mice undergoing therapy with the suicide vectors in conjunction with gancyclovir when compared with the control animals. These data suggest that the transcriptionally targeted hALA or oBLG driven expression of the HSVtk gene may be a feasible therapy for the treatment of human breast cancer.

Phase I trial of intravenous carboplatin added to oral etoposide and oral cyclophosphamide for stage IV non-small cell lung cancer

The combination of oral etoposide and oral cyclophosphamide is an active and easily administered outpatient regimen for non-small cell lung cancer with leukopenia as the most common severe toxicity. To maintain ease of outpatient administration and to take advantage of a differing dose-limiting toxicity, we attempted to add escalating doses of intravenous carboplatin to full-dose oral etoposide and oral cyclophosphamide for chemotherapy-naive patients with Stage IV non-small cell lung cancer. The first 4 patients received etoposide and cyclophosphamide (each at 50 mg PO BID Days 1-12 every 28 days) with intravenous carboplatin on Day 1 at a dose calculated by the Calvert formula to achieve AUC 4. With this regimen dose-limiting toxicity (2 patients with Grade 4 leukopenia/granulocytopenia) was noted. An additional 3 patients therefore received etoposide and cyclophosphamide at a 25% reduced dose (each at 50 mg PO BID Days 1-9 every 28 days) with intravenous carboplatin on Day 1 at a dose calculated to achieve AUC 4. Dose-limiting toxicity (2 patients with Grade 4 leukopenia/granulocytopenia) was again noted. One patient achieved a partial response maintained for 6 months. However potentiation of leukopenia/granulocytopenia by carboplatin prevents full-dose use of either cyclophosphamide and etoposide or of carboplatin in this regimen.

The effect of prolonged incubations and heat denaturation on melphalan-induced DNA cross-links as measured by the ethidium bromide fluorescence assay

Th ethidium bromide fluorescence assay detects DNA interstrand crosslinks following heat denaturation of DNA on the basis of a 20-25 fold enhancement of ethidium bromide fluorescence in the presence of double stranded DNA. This assay has been utilized to detect DNA cross-links produced by melphalan in lymphocytes from chronic lymphocytic leukemia patients. The percentage of DNA cross-links (C) in these cells did not vary linearly with the concentration of melphalan, possibly as a result of DNA fragmentation during a 16 h lysis to degrade RNA. In order to investigate this, DNA was exposed to melphalan and then the Ct was determined immediately after maximal DNA cross-link formation or after a 16 h incubation. The additional incubation period did not alter the linear relationship between Ct and melphalan concentration. Further, the DNA cross-links produced by melphalan does not appear to be heat labile since varying the heat denaturation period from 5 to 15 min had no effect on Ct. These results suggest that this assay can accurately quantitate the percentage of DNA cross-links produced by melphalan and that the curvilinear relationship between Ct and melphalan concentration in malignant human lymphocytes is not due to the ethidium bromide fluorescence assay.