Pattern of CD4 T-lymphocyte Values in Cancer Patients on Cytotoxic Therapy

New Advances in Supportive Care: Chemoprotective Agents as Novel Opportunities in Geriatric Oncology

PURPOSE OF REVIEW

To explore the effectiveness of trilaciclib and ALRN-6924 in the prevention of cancer chemotherapy-induced toxicity in older patients. New chemoprotective agents are necessary because age is the main risk factor for chemotherapy complications that account largely for the poorer outcome of cancer in the elderly. Trilaciclib and ALRN-6924 cause a reversible block of the proliferation of normal cells through cell cycle arrest (CCA). With this mechanism, they may prevent the toxicity of cycle-active cancer treatment including neutropenia, anemia, thrombocytopenia, lymphopenia, mucositis, and alopecia.

RECENT FINDINGS

Myelopoietic growth factors may prevent neutropenia in the aged, but they may cause severe bone pain, may aggravate thrombocytopenia and anemia, and may cause myelodysplasia and acute leukemia as a late complication. The prevention of thrombocytopenia, anemia, mucositis, and alopecia is unsatisfactory at present. These complications may jeopardize the treatment outcome as they require a reduction of treatment dose/intensity and because many patients find the resulting symptoms intolerable. In three studies of patients with extensive disease small cell lung cancer (ES-SCLC), trilaciclib reduced the severity and duration of neutropenia and thrombocytopenia as well as the need for blood transfusions. In addition, it produced a significant expansion of T-cell clones. Trilaciclib received FDA approval for the prevention of chemotherapy-induced myelosuppression in patients with ES-SCLC. ALRN-6924 is currently studied in phase II study of ES-SCLC. In a phase IB of 38 patients, ALRN-6924 prevented myelosuppression to an extent comparable with trilaciclib. Both drugs proved as effective in patients 65 and older as they were in the younger ones. In an "ex vivo" study, ALRN-6924 protected the epithelial stem cells of hair follicles from taxanes and promised to prevent alopecia. The possibility that CCA of tumor cells may reduce the effectiveness of cycle-active chemotherapy is a major concern. For this reason, the use of trilaciclib, an inhibitor of CDK 4/6, should be limited to tumors with inactivated RB1, and the use of ALRN-6924, an inhibitor of P53, should be limited to tumors with inactivated P53. Chemotherapy-related toxicities limit dose intensity and contribute to significant morbidity and mortality in elderly cancer patients. Trilaciclib and ALRN-6924 are of particular interest to geriatric oncologists because of their novel mechanism of action. Ameliorating chemotherapy-induced toxicities holds the promise of transforming the practice of geriatric oncology by enabling chemotherapeutic regimens that are currently not feasible for this patient population. Specifically, these agents may prevent chemotherapy-induced neutropenia and thrombocytopenia, perhaps the most life-threatening complications of cytotoxic chemotherapy, thereby obviating the need for the use of rescue strategies such as hematopoietic growth factors. In addition, these agents offer the potential for broad tissue protection from other chemotherapy-related toxicities, including mucositis, diarrhea, and alopecia, which historically have been poorly managed. Importantly, by preventing a spectrum of chemotherapy-related toxicities, these agents may permit the administration of chemotherapy at full-dose intensity, prevent functional decline, and grant maintenance of resilience to older cancer patients. As a result, the successful prevention of chemotherapy-induced side effects may not only mitigate the costs of care but also improve patient outcomes and quality of life. Finally, chemoprotective strategies offer the opportunity to apply geriatric principles to clinical trials of cancer treatment. In particular, they may allow the testing of prolongation of "active life expectancy" as a major goal of clinical trials in elderly patients. They may also enable novel and more practical forms of clinical trials. By assessing the risk of chemotherapy-related toxicity with the Chemotherapy Risk Assessment Scale for High Age Patients (CRASH) or the Cancer and Aging Research Group (CARG) instruments, these agents may permit researchers to utilize patients as their own controls and endorse the approval of supportive care drugs based upon the risk profile of individual patients.

Effect of CD4+ T cell count on treatment-emergent adverse events among patients with and without HIV receiving immunotherapy for advanced cancer

BACKGROUND

The Food and Drug Administration recommends that people living with HIV (PWH) with a CD4+ T cell count (CD4) ≥350 cells/µL may be eligible for any cancer clinical trial, but there is reluctance to enter patients with lower CD4 counts into cancer studies, including immune checkpoint inhibitor (ICI) studies. Patients with relapsed or refractory cancers may have low CD4 due to prior cancer therapies, irrespective of HIV status. It is unclear how baseline CD4 prior to ICI impacts the proportion of treatment-emergent adverse events (TEAE) and whether it differs by HIV status in ICI treated patients.

METHODS

We conducted a pilot retrospective cohort study of participants eligible for ICI for advanced cancers from three phase 1/2 trials in the USA and Spain. We determined whether baseline CD4 counts differed by HIV status and whether the effect of CD4 counts on incidence of TEAE was modified by HIV status using a multivariable logistic regression model.

RESULTS

Of 122 participants, 66 (54%) were PWH who received either pembrolizumab or durvalumab and 56 (46%) were HIV-negative who received bintrafusp alfa. Median CD4 at baseline was 320 cells/µL (IQR 210-495) among PWH and 356 cells/µL (IQR 260-470) among HIV-negative participants (p=0.5). Grade 3 or worse TEAE were recorded among 7/66 (11%) PWH compared with 7/56 (13%) among HIV-negative participants. When adjusted for prior therapies, age, sex, and race, the effect of baseline CD4 on incidence of TEAE was not modified by HIV status for any TEAE (interaction term p=0.7), or any grade ≥3 TEAE (interaction term p=0.1).

CONCLUSIONS

There was no significant difference in baseline CD4 or the proportions of any TEAE and grade ≥3 TEAE by HIV status. CD4 count thresholds for cancer clinical trials should be carefully reviewed to avoid unnecessarily excluding patients with HIV and cancer.

Mathematical modeling of tumor-immune system interactions: the effect of rituximab on breast cancer immune response

tBregs are a newly discovered subcategory of B regulatory cells, which are generated by breast cancer, resulting in the increase of Tregs and therefore in the death of NK cells. In this study, we use a mathematical and computational approach to investigate the complex interactions between the aforementioned cells as well as CD8⁺ T cells, CD4⁺ T cells and B cells. Furthermore, we use data fitting to prove that the functional response regarding the lysis of breast cancer cells by NK cells has a ratio-dependent form. Additionally, we include in our model the concentration of rituximab - a monoclonal antibody that has been suggested as a potential breast cancer therapy - and test its effect, when the standard, as well as experimental dosages, are administered.

Modulation of the tumor microenvironment (TME) by melatonin

The tumor microenvironment (TME) includes a number of non-cancerous cells that affect cancer cell survival. Although CD8+ T lymphocytes and natural killer (NK) cells suppress tumor growth through induction of cell death in cancer cells, there are various immunosuppressive cells such as regulatory T cells (Tregs), tumor-associated macrophages (TAMs), cancer-associated fibroblasts (CAFs), myeloid-derived suppressor cells (MDSCs), etc., which drive cancer cell proliferation. These cells may also support tumor growth and metastasis by stimulating angiogenesis, epithelial-mesenchymal transition (EMT), and resistance to apoptosis. Interactions between cancer cells and other cells, as well as molecules released into EMT, play a key role in tumor growth and suppression of antitumoral immunity. Melatonin is a natural hormone that may be found in certain foods and is also available as a drug. Melatonin has been demonstrated to modulate cell activity and the release of cytokines and growth factors in TME. The purpose of this review is to explain the cellular and molecular mechanisms of cancer cell resistance as a result of interactions with TME. Next, we explain how melatonin affects cells and interactions within the TME.

Vitamin D Assessment Over 48 Weeks in Treatment-Naive HIV Individuals Starting Lopinavir/Ritonavir Monotherapy

BACKGROUND

Vitamin D deficiency is common in HIV population and has been associated with increased comorbidity risk and poor immunologic status.

OBJECTIVE

To evaluate the effect of protease inhibitor lopinavir/ritonavir monotherapy on changes in serum 25-hydroxyvitamin D [25(OH)D] over 48 weeks.

METHODS

Thirty-four treatment-naïve HIV individuals initiating lopinavir/ritonavir monotherapy and receiving clinical care from private practice in Houston, Texas, were included. Serum 25-hydroxyvitamin D levels from stored plasma samples collected from IMANI-2 pilot study at both baseline and 48 weeks were analyzed using LC-MS assays. Mean 25(OH)D at baseline and 48 weeks were compared using paired t-tests. Linear regression analysis was used to evaluate factors associated with changes in 25(OH)D. Logistic regression analyses were used to determine the effect of vitamin D status and covariates on CD4 cell count recovery.

RESULTS

Mean 25(OH)D was significantly higher at 48 weeks (26.3 ng/mL (SD + 14.9); p=0.0003) compared to baseline (19.8 ng/mL (SD +12.1), with fewer individuals having vitamin D deficiency (41.2%) and severe deficiency (11.8%). Both body mass index and baseline CD4 cell count were significant independent covariates associated with 25(OH)D changes over 48 weeks. Baseline vitamin D status did not affect CD4 cell count recovery. However, in a 24-week multivariate analysis, current tobacco use was significantly associated with a decreased odds of CD4 cell count recovery (AOR 0.106, 95% CI 0.018-0.606; p=0.012).

CONCLUSION

Individuals treated with lopinavir/ritonavir monotherapy had significantly higher 25(OH)D after 48 weeks. Current tobacco users had significantly diminished CD4 cell count recovery after starting treatment, warranting further clinical investigation.

Incidence, clinical presentation, and outcomes of Pneumocystis pneumonia when utilizing Polymerase Chain Reaction-based diagnosis in patients with Hodgkin lymphoma

A Polymerase Chain Reaction-based diagnosis of Pneumocystis Pneumonia (PCP) and the need for anti-Pneumocystis prophylaxis in Hodgkin lymphoma patients receiving chemotherapy requires further investigation. This retrospective, single-center, study evaluated 506 consecutive adult patients diagnosed with Hodgkin lymphoma receiving chemotherapy between January 2006 and August 2018. The cumulative incidence of PCP 1 year after start of chemotherapy was 6.2% (95% CI 3.8-8.5%). Mortality 30 days from PCP diagnosis was 8% (n = 2) with one death attributable to PCP. Bleomycin-containing combination chemotherapy regimen was not significantly associated with a higher risk for PCP when compared to other regimens (HR = 1.59, 95% CI 0.55-4.62 p = 0.40). Anti-Pneumocystis prophylaxis was not significantly associated with a decreased incidence of PCP (HR = 0.51, 95% CI 0.15-1.71, p = 0.28). As the overall incidence is above the commonly accepted 3.5% threshold, clinicians should consider the potential value of prophylaxis. The utility of universal vs. targeted anti-Pneumocystis prophylaxis requires prospective, randomized investigation.

Immune Status and Associated Mortality After Cancer Treatment Among Individuals With HIV in the Antiretroviral Therapy Era

Importance

Immunologic decline associated with cancer treatment in people with HIV is not well characterized. Quantifying excess mortality associated with cancer treatment-related immunosuppression may help inform cancer treatment guidelines for persons with HIV.

Objective

To estimate the association between cancer treatment and CD4 count and HIV RNA level in persons with HIV and between posttreatment CD4 count and HIV RNA trajectories and all-cause mortality.

Design, Setting, and Participants

This observational cohort study included 196 adults with HIV who had an incident first cancer and available cancer treatment data while in the care of The Johns Hopkins HIV Clinic from January 1, 1997, through March 1, 2016. The study hypothesized that chemotherapy and/or radiotherapy in people with HIV would increase HIV RNA levels owing to treatment tolerability issues and would be associated with a larger initial decline in CD4 count and slower CD4 recovery compared with surgery or other treatment. An additional hypothesis was that these CD4 count declines would be associated with higher mortality independent of baseline CD4 count, antiretroviral therapy use, and risk due to the underlying cancer. Data were analyzed from December 1, 2017, through April 1, 2018.

Exposures

Initial cancer treatment category (chemotherapy and/or radiotherapy vs surgery or other treatment).

Main Outcomes and Measures

Post-cancer treatment longitudinal CD4 count, longitudinal HIV RNA level, and all-cause mortality.

Results

Among the 196 participants (135 [68.9%] male; median age, 50 [interquartile range, 43-55] years), chemotherapy and/or radiotherapy decreased initial CD4 count by 203 cells/μL (95% CI, 92-306 cells/μL) among those with a baseline CD4 count of greater than 500 cells/μL. The decline for those with a baseline CD4 count of no greater than 350 cells/μL was 45 cells/μL (interaction estimate, 158 cells/μL; 95% CI, 31-276 cells/μL). Chemotherapy and/or radiotherapy had no detrimental association with HIV RNA levels. After initial cancer treatment, every 100 cells/μL decrease in CD4 count resulted in a 27% increase in mortality (hazard ratio, 1.27; 95% CI, 1.08-1.53), adjusting for HIV RNA level. No significant increase in mortality was associated with a unit increase in log10 HIV RNA after adjusting for CD4 count (hazard ratio, 1.24; 95% CI, 0.94-1.65).

Conclusions and Relevance

In this study, chemotherapy and/or radiotherapy was associated with significantly reduced initial CD4 count in adults with HIV compared with surgery or other treatment. Lower CD4 count after cancer treatment was associated with an increased hazard of mortality. Further research is necessary on the immunosuppressive effects of cancer treatment in adults with HIV and whether health care professionals must consider the balance of cancer treatment efficacy against the potential cost of further immunosuppression. Monitoring of immune status may also be helpful given the decrease in CD4 count after treatment and the already immunocompromised state of patients with HIV.