scholarly journals Spatial heterogeneity and evolutionary dynamics modulate time to recurrence in continuous and adaptive cancer therapies

2017 ◽  
Author(s):  
Jill A. Gallaher ◽  
Pedro M. Enriquez-Navas ◽  
Kimberly A. Luddy ◽  
Robert A. Gatenby ◽  
Alexander R. A. Anderson

AbstractTreatment of advanced cancers has benefited from new agents that supplement or bypass conventional therapies. However, even effective therapies fail as cancer cells deploy a wide range of resistance strategies. We propose that evolutionary dynamics ultimately determine survival and proliferation of resistant cells, therefore evolutionary strategies should be used with conventional therapies to delay or prevent resistance. Using an agent-based framework to model spatial competition among sensitive and resistant populations, we apply anti-proliferative drug treatments to varying ratios of sensitive and resistant cells. We compare a continuous maximum tolerated dose schedule with an adaptive schedule aimed at tumor control through competition between sensitive and resistant cells. We find that continuous treatment cures mostly sensitive tumors, but with any resistant cells, recurrence is inevitable. We identify two adaptive strategies that control heterogeneous tumors: dose modulation controls most tumors with less drug, while a more vacation-oriented schedule can control more invasive tumors.

2021 ◽  
Author(s):  
Masud M.A ◽  
Jae-Young Kim ◽  
Cheol-Ho Pan ◽  
Eunjung Kim

A long-standing practice in the treatment of cancer is that of hitting hard with the maximum tolerated dose to eradicate tumors. This continuous therapy, however, selects for resistant cells, leading to the failure of the treatment. A different type of treatment strategy, adaptive therapy, has recently been shown to have a degree of success in both preclinical xenograft experiments and clinical trials. Adaptive therapy is used to maintain a tumor's volume by exploiting the competition between drug-sensitive and drug-resistant cells with minimum effective drug doses or timed drug holidays. To further understand the role of competition in the outcomes of adaptive therapy, we developed a 2D on-lattice agent-based model. Our simulations show that the superiority of the adaptive strategy over continuous therapy depends on the local competition shaped by the spatial distribution of resistant cells. Cancer cell migration and increased carrying capacity accelerate the progression of the tumor under both types of treatments by reducing the spatial competition. Intratumor competition can also be affected by fibroblasts, which produce microenvironmental factors that promote cancer cell growth. Our simulations show that the spatial architecture of fibroblasts modulates the benefits of adaptive therapy. Finally, as a proof of concept, we simulated the outcomes of adaptive therapy in multiple metastatic sites composed of different spatial distributions of fibroblasts and drug-resistant cell populations.


1998 ◽  
Vol 16 (11) ◽  
pp. 3528-3536 ◽  
Author(s):  
N C Choi ◽  
J E Herndon ◽  
J Rosenman ◽  
R W Carey ◽  
C T Chung ◽  
...  

PURPOSE An improvement in radiation dose schedule is necessary to increase local tumor control and survival in limited-stage small-cell lung cancer. The goal of this study was to determine the maximum-tolerated dose (MTD) of radiation (RT) in both standard daily and hyperfractionated-accelerated (HA) twice-daily RT schedules in concurrent chemoradiation. METHODS The study design consisted of a sequential dose escalation in both daily and HA twice-daily RT regimens. RT dose to the initial volume was kept at 40 to 40.5 Gy, while it was gradually increased to the boost volume by adding a 7% to 11 % increment of total dose to subsequent cohorts. The MTD was defined as the radiation dose level at one cohort below that which resulted in more than 33% of patients experiencing grade > or = 4 acute esophagitis and/or grade > or = 3 pulmonary toxicity. The study plan included nine cohorts, five on HA twice-daily and four on daily regimens for the dose escalation. Chemotherapy consisted of three cycles of cisplatin 33 mg/m2/d on days 1 to 3 over 30 minutes, cyclophosphamide 500 mg/m2 on day 1 intravenously (IV) over 1 hour, and etoposide 80 mg/m2/d on days 1 to 3 over 1 hour every 3 weeks (PCE) and two cycles of PE. RT was started at the initiation of the fourth cycle of chemotherapy. RESULTS Fifty patients were enrolled onto the study. The median age was 60 years (range, 38-79), sex ratio 2.3:1 for male to female, weight loss less than 5% in 73%, and performance score 0 to 1 in 94% and 2 in 6% of patients. In HA twice-daily RT, grade > or = 4 acute esophagitis was noted in two of five (40%), two of seven (29%), four of six (67%), and five of six patients (86%) at 50 (1.25 Gy twice daily), 45, 50, and 55.5 Gy in 1.5 Gy twice daily, 5 d/wk, respectively. Grade > or = 3 pulmonary toxicity was not seen in any of these 24 patients. Therefore, the MTD for HA twice-daily RT was judged to be 45 Gy in 30 fractions over 3 weeks. In daily RT, grade > or = 4 acute esophagitis was noted in zero of four, zero of four, one of five (20%), and two of six patients (33%) at 56, 60, 66, and 70 Gy on a schedule of 2 Gy per fraction per day, five fractions per week. Grade > or = 3 pneumonitis was not observed in any of the 19 patients. Thus, the MTD for daily RT was judged to be at least 70 Gy in 35 fractions over 7 weeks. Grade 4 granulocytopenia and thrombocytopenia were observed in 53% and 6% of patients, respectively, during the first three cycles of PCE. During chemotherapy cycles 4 to 5, grade 4 granulocytopenia and thrombocytopenia were noted in 43% and 29% of patients at 45 Gy in 30 fractions over 3 weeks (MTD) by HA twice-daily RT and 50% and 17% at 70 Gy in 35 fractions over 7 weeks (MTD) by daily RT, respectively. The overall tumor response consisted of complete remission (CR) in 51% (24 of 47), partial remission (PR) in 38% (1 8 of 47), and stable disease in 2% (one of 47). The median survival time of all patients was 24.4 months and 2- and 3-year survival rates were 53% and 28%, respectively. With regard to the different radiation schedules, 2- and 3-year survival rates were 52% and 25% for the HA twice-daily and 54% and 35% for the daily RT cohorts. CONCLUSION The MTD of HA twice-daily RT was determined to be 45 Gy in 30 fractions over 3 weeks, while it was judged to be at least 70 Gy in 35 fractions over 7 weeks for daily RT. A phase III randomized trial to compare standard daily RT with HA twice-daily RT at their MTD for local tumor control and survival would be a sensible research in searching for a more effective RT dose-schedule than those that are being used currently.


2018 ◽  
Vol 115 (44) ◽  
pp. E10407-E10416 ◽  
Author(s):  
Benjamin H. Good ◽  
Stephen Martis ◽  
Oskar Hallatschek

Microbial communities can evade competitive exclusion by diversifying into distinct ecological niches. This spontaneous diversification often occurs amid a backdrop of directional selection on other microbial traits, where competitive exclusion would normally apply. Yet despite their empirical relevance, little is known about how diversification and directional selection combine to determine the ecological and evolutionary dynamics within a community. To address this gap, we introduce a simple, empirically motivated model of eco-evolutionary feedback based on the competition for substitutable resources. Individuals acquire heritable mutations that alter resource uptake rates, either by shifting metabolic effort between resources or by increasing the overall growth rate. While these constitutively beneficial mutations are trivially favored to invade, we show that the accumulated fitness differences can dramatically influence the ecological structure and evolutionary dynamics that emerge within the community. Competition between ecological diversification and ongoing fitness evolution leads to a state of diversification–selection balance, in which the number of extant ecotypes can be pinned below the maximum capacity of the ecosystem, while the ecotype frequencies and genealogies are constantly in flux. Interestingly, we find that fitness differences generate emergent selection pressures to shift metabolic effort toward resources with lower effective competition, even in saturated ecosystems. We argue that similar dynamical features should emerge in a wide range of models with a mixture of directional and diversifying selection.


2020 ◽  
Vol 375 (1808) ◽  
pp. 20190598 ◽  
Author(s):  
Laura Grieneisen ◽  
Amanda L. Muehlbauer ◽  
Ran Blekhman

Recent comparative studies have found evidence consistent with the action of natural selection on gene regulation across primate species. Other recent work has shown that the microbiome can regulate host gene expression in a wide range of relevant tissues, leading to downstream effects on immunity, metabolism and other biological systems in the host. In primates, even closely related host species can have large differences in microbiome composition. One potential consequence of these differences is that host species-specific microbial traits could lead to differences in gene expression that influence primate physiology and adaptation to local environments. Here, we will discuss and integrate recent findings from primate comparative genomics and microbiome research, and explore the notion that the microbiome can influence host evolutionary dynamics by affecting gene regulation across primate host species. This article is part of the theme issue ‘The role of the microbiome in host evolution’.


2000 ◽  
Vol 18 (17) ◽  
pp. 3151-3163 ◽  
Author(s):  
Eric K. Rowinsky ◽  
Thomas R. Johnson ◽  
Charles E. Geyer ◽  
Lisa A. Hammond ◽  
S. Gail Eckhardt ◽  
...  

PURPOSE: To assess the feasibility of administering DX-8951f (exatecan mesylate), a water-soluble, camptothecin analog, as a 30-minute intravenous infusion daily for 5 days every 3 weeks, determine the maximum-tolerated dose (MTD) and pharmacokinetic (PK) behavior of DX-8951f, and seek preliminary evidence of anticancer activity. PATIENTS AND METHODS: Patients with advanced solid malignancies were treated with escalating doses of DX-8951f. After three patients were treated at the first dose level, doses were to be escalated in increments of 100%, using a single patient at each dose level unless moderate toxicity was observed. The MTD, defined as the highest dose level at which the incidence of dose-limiting toxicity did not exceed 20%, was calculated separately for minimally pretreated (MP) and heavily pretreated (HP) patients. The PK and excretory profiles of DX-8951, the anhydrous form of DX-8951f, were also characterized. RESULTS: Thirty-six patients were treated with 130 courses of DX-8951f at six dose levels ranging from 0.1 to 0.6 mg/m2/d. Brief, noncumulative neutropenia was the most common toxicity observed. Severe myelosuppression (neutropenia that was protracted and/or associated with fever and/or severe thrombocytopenia) was consistently experienced by HP and MP patients at doses exceeding 0.3 and 0.5 mg/m2/d, respectively. Nonhematologic toxicities (nausea, vomiting, and diarrhea) were also observed, but these effects were rarely severe. Objective antitumor activity included partial responses in one patient each with platinum-resistant extrapulmonary small-cell and fluoropyrimidine- and irinotecan-resistant colorectal carcinoma, and minor responses in patients with prostate, hepatocellular, thymic, primary peritoneal, and irinotecan-resistant colorectal carcinomas. The PKs of total DX-8951 were linear and well fit by a three-compartment model. CONCLUSION: The recommended doses for phase II studies of DX-8951f as a 30-minute infusion daily for 5 days every 3 weeks are 0.5 and 0.3 mg/m2/d for MP and HP patients, respectively. The characteristics of the myelosuppressive effects of DX-8951f, paucity of severe nonhematologic toxicities, and antitumor activity against a wide range of malignancies warrant broad disease-directed evaluations of DX-8951f on this schedule.


Genes ◽  
2019 ◽  
Vol 10 (5) ◽  
pp. 336 ◽  
Author(s):  
Justin P. Blumenstiel

Transposable elements (TEs) can be maintained in sexually reproducing species even if they are harmful. However, the evolutionary strategies that TEs employ during proliferation can modulate their impact. In this review, I outline the different life stages of a TE lineage, from birth to proliferation to extinction. Through their interactions with the host, TEs can exploit diverse strategies that range from long-term coexistence to recurrent movement across species boundaries by horizontal transfer. TEs can also engage in a poorly understood phenomenon of TE resurrection, where TE lineages can apparently go extinct, only to proliferate again. By determining how this is possible, we may obtain new insights into the evolutionary dynamics of TEs and how they shape the genomes of their hosts.


1998 ◽  
Vol 16 (6) ◽  
pp. 2169-2180 ◽  
Author(s):  
A L Yu ◽  
M M Uttenreuther-Fischer ◽  
C S Huang ◽  
C C Tsui ◽  
S D Gillies ◽  
...  

PURPOSE To evaluate the toxicity, immunogenicity, and pharmacokinetics of a human-mouse chimeric monoclonal antibody (mAb) ch 14.18 directed against disialoganglioside (GD2) and to obtain preliminary information on its clinical efficacy, we conducted a phase I trial in 10 patients with refractory neuroblastoma and one patient with osteosarcoma. PATIENTS AND METHODS Eleven patients were entered onto this phase I trial. They received 20 courses of mAb ch 14.18 at dose levels of 10, 20, 50, 100, and 200 mg/m2. Dose escalation was performed in cohorts of three patients; intrapatient dose escalation was also permitted. RESULTS The most prevalent toxicities were pain, tachycardia, hypertension, fever, and urticaria. Most of these toxicities were dose-dependent and rarely noted at dosages of 20 mg/m2 and less. Although the maximum-tolerated dose was not reached in this study, clinical responses were observed. These included one partial (PR) and four mixed responses (MRs) and one stable disease (SD) among 10 assessable patients. Biologic activity of ch 14.18 in vivo was shown by binding of ch 14.18 to tumor cells and complement-dependent cytotoxicity of posttreatment sera against tumor target cells. An anti-ch 14.18 immune response was detectable in seven of 10 patients studied. CONCLUSION In summary, with the dose schedule used, ch 14.18 appears to be clinically safe and effective, and repeated mAb administration was not associated with increased toxicities. Further clinical trials of mAb ch 14.18 in patients with neuroblastoma are warranted.


2009 ◽  
Vol 27 (15_suppl) ◽  
pp. e14505-e14505
Author(s):  
Y. Ito ◽  
K. Hatake ◽  
S. Takahashi ◽  
M. Yokoyama ◽  
M. Suenaga ◽  
...  

e14505 Background: Neratinib (HKI-272) is a potent irreversible pan-ErbB tyrosine kinase inhibitor. In non-Japanese pts, neratinib was found to have clinical activity against solid tumors and dose-limiting toxicity (DLT) of diarrhea. The maximum tolerated dose (MTD) was 320 mg daily and the recommended dose (RD) was 240 mg because of the diarrhea. In this phase 1 study, the MTD was determined and safety and preliminary efficacy were assessed in Japanese pts with advanced solid tumors. Methods: Pts (3- 6/cohort) received 80, 160, 240, or 320 mg oral neratinib. Each pt participated in only 1 dose group and received single doses of neratinib followed by 1 wk of observation; pts then received daily continuous administration at the same dose. DLTs were assessed from the first single dose to the end of 14 days of continuous treatment. Pharmacokinetics (PK) will be analysed via a noncompartmental method. Tumor measurements were made at screening and at the end of every 8 weeks (2 cycles) by RECIST. Results: Preliminary data for 21 pts as of 30 Oct 2008 are presented. Pts had a median age [range] of 61 yrs [39–78], were 62% male, and had all received ≥2 prior chemotherapy regimens. Tumor types at primary diagnosis were advanced colorectal (81%), breast (14%), and gastric (5%) cancer. Median duration of neratinib treatment [range] was 10 wks [3–29].Two patients at the 320-mg dose had DLTs of diarrhea plus anorexia. Therefore the MTD was determined to be 240 mg. Neratinib-related AEs, any grade in ≥25% of pts included diarrhea (95%), fatigue (67%), anorexia (43%), nausea (43%), abdominal pain (38%), decreased hemoglobin (38%), increased AST (33%), and rash (29%). Neratinib-related AEs, grade ≥3 in ≥1 pts were anorexia (3 pts) and diarrhea (2 pts). Two pts had partial response (PR), 8 pts had stable disease (SD) ≥8 wks, 2 had SD≥16 wks, 9 had progressive disease. The 2 pts with PR had ErbB-2+ advanced breast cancer. PK analysis is still ongoing. Conclusions: In Japanese pts, the MTD for neratinb was determined to be 240 mg and the RD will be confirmed as 240 mg. Neratinib is tolerable and demonstrates preliminary antitumor activity in pts with solid tumors. [Table: see text]


2012 ◽  
Vol 30 (15_suppl) ◽  
pp. e13077-e13077
Author(s):  
Kyriakos P. Papadopoulos ◽  
David S. Mendelson ◽  
Anthony W. Tolcher ◽  
Howard A. Burris ◽  
Michael S. Gordon ◽  
...  

e13077 Background: Oprozomib (ONX0912), a structural analog of carfilzomib, is an orally bioavailable proteasome inhibitor that irreversibly binds to its target and is being evaluated in hematologic malignancies and solid tumors (ST). In a dose-escalation study of once-daily (qd) ONX0912, the maximum tolerated dose (MTD) was 150 mg/d. The protocol was subsequently amended to investigate the effects of a split-dose schedule. Presented here are the interim results from this patient (pt) group. Methods: This is an ongoing, phase 1 study in pts with advanced refractory or recurrent ST. The primary objective is to evaluate the safety and tolerability of ONX0912 and determine the MTD. ONX0912 is administered for 5 consecutive days in 14-day cycles. For pts under the amended regimen, treatment is initiated at 60 mg BID, with 4–6 h between doses. Daily doses are escalated in 30 mg increments in successive groups of 3 pts. Groups are expanded to include 6 pts in the event of a dose-limiting toxicity (DLT) or if the MTD is reached. All AEs, including serious AEs (SAEs), are defined per protocol and collected from screening to 30 days after the last dose. Results: 13 pts received a split dose of ONX0912 (4 pts: 60 mg BID; 3 pts: 90/60 mg; 6 pts: 90 mg BID). At least 1 dose reduction was required by 1 pt in the 90/60 mg group and 2 pts in the 90 mg BID group. 9 pts reported treatment-related GI AEs (vomiting, n=9; nausea, n=8; diarrhea, n=5). 2 SAEs, arthralgia and mental status change, were reported at 60 mg BID. 2 SAEs resulting in a dose delay were reported at 90/60 mg (Grade 3/4 anemia [ongoing, also required a dose reduction] and reversible fatigue). There was 1 DLT at 90 mg BID (Grade 3 reversible hypophosphatemia), and this cohort was therefore expanded. Treatment-related vomiting led to discontinuation for 1 patient at 60 mg BID. No AEs led to early withdrawal, and no deaths have been reported in the study. Conclusions: With qd administration, the MTD of ONX0912 was established at 150 mg/d. However, the MTD has not been reached on the split-dose regimen at cumulative doses up to 180 mg/d (90 mg BID). GI AEs were the most common treatment-related AEs. Based on these preliminary observations, split-dose ONX0912 may improve tolerability over qd dosing.


2017 ◽  
Vol 35 (15_suppl) ◽  
pp. 9549-9549 ◽  
Author(s):  
Celine Boutros ◽  
Christine Mateus ◽  
Emilie Lanoy ◽  
Emilie Routier ◽  
Salem Chouaib ◽  
...  

9549 Background: Preclinical findings have shown a synergy between RT and anti-CTLA-4 monoclonal antibody in several tumor animal models for both local tumor control and distant effects. Preliminary clinical data suggest that it could be due to an abscopal effect of RT. The Mel-Ipi-Rx phase 1 study aimed to determine the maximum tolerated dose (MTD) and safety profile of RT combined with ipilimumab in pts with metastatic melanoma. Methods: A 3+3 dose escalation design was used with 9, 15, 18 and 24 Gy dose of RT (in 3 fractions) at week 4 combined with 10 mg/kg ipilimumab (every 3 weeks for 4 doses). Pts with evidence of clinical benefit at week 12 were eligible for maintenance ipilimumab at 10 mg/kg every 12 weeks starting at week 24 until severe toxicity or disease progression based on immune-related response criteria (irRC). Results: 19 pts with advanced melanoma received ipilimumab between August 2011 and July 2015. Nine pts received the 4 doses of ipilimumab and 2 pts received maintenance ipilimumab (1 and 2 cycles respectively). All pts received the combined RT at week 4 in 3 fractions. All pts presented at least one AE of any grade. The most common AEs were asthenia, diarrhea, desease-related pain and fever. Grade 3 AEs occurred in 8 pts. They included colitis (n = 3), hepatitis (n = 2), anemia (n = 2), asthenia (n = 1), thyroid disorders (n = 1) and nausea/vomiting (n = 1). Nine pts discontinued the study owing to treatment-related adverse events including colitis (n = 6), hepatitis (n = 2) and DRESS (Drug Rash with Eosinophilia and systemic syndrome) (n = 1). DLT occurred in 2/6 pts in the cohort receiving 15 Gy. No drug-related death occurred. According to irRC, 4 partial responses (ORR: 21%) and 4 stable diseases were observed at week 24. The MTD was 9 Gy dose. One pt out of 12 treated in the 9 Gy cohort presented a DLT (grade 3 colitis). The median progression-free survival [95% CI] was 7.2 months [2.4 – 16.8]. The median overall survival [95% CI] was 14.4 months [7.2 – 20.4]. Conclusions: When combined with ipilimumab at 10 mg/kg, in the present design, the MTD of RT was 9 Gy. This combination appears to be associated with antitumor activity. Clinical trial information: 2010-020317-93.


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