First-line chemotherapy for advanced ovarian cancer: paclitaxel, cisplatin and the evidence

Role of microRNAs in ovarian cancer pathogenesis and potential clinical implications

Despite important improvements over the past two decades, the overall cure rate of epithelial ovarian cancer (EOC) remains only approximately 30%. Although much has been learned about the proteins and pathways involved in early events of malignant transformation and drug resistance, a major challenge still remaining is the identification of markers for early diagnosis and prediction of response to chemotherapy. Recently, it has become clear that alterations in the expression of microRNAs (miRNAs) contribute to the pathogenesis and progression of several human malignancies. In this review we discuss current data concerning the accumulating evidence of the role of miRNAs in EOC pathogenesis and tumor characterization; their dysregulated expression in EOC; and their still undefined role in diagnosis, prognosis and prediction of response to therapy. The most frequently deregulated miRNAs are members of the let-7 and miR-200 families, the latter involved in epithelial-to-mesenchymal transition (EMT). EMT is part of normal ovarian surface epithelium physiology, being the key regulator of the post-ovulatory repair process, and failure to undergo EMT may be one of the events leading to transformation. A general down-modulation of miRNA expression is observed in EOC compared to normal tissue. However, a clear consensus on the miRNA signatures associated with prognosis or prediction of response to therapy has not yet been reached.

Second-line chemotherapy with pegylated liposomal doxorubicin and carboplatin is highly effective in patients with advanced ovarian cancer in late relapse: a GINECO phase II trial

BACKGROUND

Platinum-based chemotherapy is standard second-line treatment of patients with advanced ovarian cancer (AOC) in late relapse. Pegylated liposomal doxorubicin (PLD) has significant single-agent activity in this setting. Therefore, we evaluated the use of PLD plus carboplatin in this patient population.

PATIENTS AND METHODS

PLD 30 mg/m(2) followed by carboplatin at area under the curve (AUC) 5 mg.min/ml, repeated every 28 days for a maximum of nine cycles, was administered to 104 women with AOC relapsing >or=6 months after completion of first- or second-line therapy with platinum-taxane-based regimens.

RESULTS

Overall response was 63%, with a 38% complete response, median progression-free survival of 9.4 months, and median overall survival (OS) of 32 months. Grade 3 or 4 neutropenia occurred in 51% of patients, but febrile neutropenia in only 3%. Nonhematologic toxic effects were primarily grades 1 and 2, with low rates of alopecia and neurotoxicity.

CONCLUSIONS

PLD plus carboplatin is highly effective, prolongs OS, and is well tolerated in women with AOC in late relapse previously treated with both platinum and taxanes. Evaluation of this regimen in phase III trials is warranted.

Survival in ovarian cancer in Wales: prior to introduction of all Wales guidelines

The objective of the study was to review referral practice, overall management, and survival in women with suspected ovarian cancer in Wales. This study was done prior to introduction of cancer management guidelines in the region. A confidential study questionnaire was sent to 20 participating hospitals. Data on 287 consecutive women with suspected ovarian cancer were collected, of which 250 women underwent primary laparotomy. Information was obtained on referral pattern, preoperative investigations, place of primary surgery, specialty of the primary surgeon, surgical parameters recorded at the time of operation, a final overall stage, adjuvant treatment, and survival outcome. There was a wide variation in referral practice and management of ovarian cancer in Wales. Stage of the disease, attempt at optimal debulking, residual disease, management by a cancer centre multidisciplinary team, and platinum-based chemotherapy were associated with improved overall survival and progression-free survival. More women were alive if managed in the cancer centre at 1 and 3 year after diagnosis (P = 0.022). This study has highlighted the acute issue of the standards of clinical care in the area of ovarian cancer management and will emphasize the implementation of better care pathways for ovarian cancers.

JNK1-dependent antimitotic activity of thiazolidin compounds in human non-small-cell lung and colon cancer cells

We recently identified two thiazolidin compounds, 5-[(4-methylphenyl)methylene]-2-(phenylamino)-4(5H)-thiazolone (MMPT) and 5-(2,4-dihydroxybenzylidene)-2-(phenylimino)-1,3-thiazolidin (DBPT), that inhibit the growth of human non-small-cell lung and colon cancer cells independent of P-glycoprotein and p53 status. Here we further investigated the mechanism by which these thiazolidin compounds mediate their anticancer effects. Treatment of cancer cells with MMPT and DBPT led to a time-dependent accumulation of cells arrested in the G2/M phase with modulation of the expression of proteins such as cyclin B1, cdc25C, and phosphorylated histone H3. Moreover, treatment with MMPT and DBPT increased M-phase arrest with abnormal spindle formation. DBPT-mediated G2/M phase arrest and phosphorylation of cdc25C and histone H3 were abrogated when JNK activation was blocked either with SP600125, a specific JNK inhibitor, or a dominant-negative JNK1 gene. Moreover, DBPT-mediated microtubule disruption was also blocked by SP600125 treatment. Our results demonstrate that thiazolidin compounds can effectively induce G2/M arrest in cancer cells and that this G2/M arrest requires JNK activation.

p53 Gene Status and Response to Topotecan-Containing Chemotherapy in Advanced Ovarian Carcinoma

OBJECTIVE

Since the p53 gene has been identified as a determinant of response to chemotherapy in ovarian carcinoma in previous studies, we investigated the significance of the p53 status in response to topotecan as second-line therapy.

METHODS

Twenty-eight patients with advanced ovarian carcinoma, pretreated with standard platinum/paclitaxel chemotherapy, received topotecan as single-agent second-line therapy. Tumors were investigated by molecular analysis for p53 mutations in tumor samples obtained at primary surgery (i.e. before first-line therapy).

RESULTS

Wild-type p53 tumors responsive to first-line therapy maintained substantial responsiveness to topotecan. In contrast, p53 mutation was associated with a low responsiveness to second-line therapy.

CONCLUSIONS

The better outcome in relapsed patients with wild-type p53 suggests that the presence of a functional wild-type p53 confers stability of the drug-sensitive phenotype. This outcome is consistent with the clinical observation that the efficacy of topotecan in the treatment of relapsed ovarian carcinoma patients is dependent on platinum sensitivity, because platinum-sensitive tumors are expected to carry wild-type p53. Although untreated mutant p53 tumors may be responsive to first-line paclitaxel-containing therapy, it is likely that loss of p53 leads to genomic instability resulting in rapid progression to drug resistance.

Sequential single agents as first-line chemotherapy for ovarian cancer: a strategy derived from the results of GOG-132

First-line chemotherapy for ovarian cancer during the past decade has evolved toward the use of carboplatin and paclitaxel combinations. This has been based on randomized trials showing that combinations of these two drugs lead to a outcome similar to that obtained using cisplatin and paclitaxel (that had, in turn, proven superior in progression-free survival and overall survival to cisplatin and cyclophosphamide) but with less toxicity. Surprisingly, taxane-platinum combinations were not superior to control arms in two studies (ICON3 and GOG-132) utilizing carboplatin or cisplatin as the comparators. This has renewed interest in the role of single agents in first-line chemotherapy - a concept also supported by a number of prior clinical trials with single-agent platinum compounds yielding results not inferior to combinations. Early 'pre-emptive' crossover (prior to the stipulated clinical progression) to paclitaxel or a paclitaxel-containing regimen, however, occurred in 24% of patients initially treated with cisplatin on GOG-132. This has led to the interpretation of this trial as a combination versus sequential design. Although not subscribing to this interpretation, the results of GOG-132 and ICON3 not only raise doubts over a clear superiority of combinations over single agents but also lead to a consideration of sequential treatment designs for first line. Advantages of such designs are: (a) ability to provide 'dose-dense' platinums followed by 'dose-dense' paclitaxel and, perhaps, other drugs; and (b) the potential of acquiring biological data linked to the antitumor effects of a specific drug. Mathematical modeling and recent positive results in breast cancer adjuvant therapy support the use of 'dose-dense' strategies, and these should be considered in the design of future trials in ovarian cancer.

Inhibition of microtubule polymerization by 3-bromopropionylamino benzoylurea (JIMB01), a new cancericidal tubulin ligand

3-Bromopropionylamino benzoylurea (JIMB01) is a small molecular weight compound (MW 313) that has been synthesized in our laboratory. This compound showed antiproliferative activities in a panel of thirteen human tumor cell lines with IC(50) values in the range of 0.25 to 0.51 micro M for leukemia and lymphoma cell lines and 0.33 to 9.26 micro M for solid tumor cell lines. The primary action of JIMB01 is to inhibit microtubule polymerization but not depolymerization. A 4 micro M concentration of the compound caused a complete inhibition of microtubule assembly in a cell-free reaction. An increase in the number of human hepatocarcinoma cells blocked in the M-phase was detected 12hr after exposure to JIMB01. The kinase activity of cyclin B1, which is responsible for the G(2)/M transition, was increased accordingly. Bcl-2 phosphorylation became visible, in a western blot, within 6hr in hepatocarcinoma cells treated with JIMB01 at 0.8 micro M or higher. JIMB01-induced apoptosis in liver cancer cells was confirmed by morphological methods, flow cytometry, as well as DNA gel electrophoresis, which clearly demonstrated DNA degradation in the form of a multiple-unit DNA ladder. Furthermore, in vivo experiments using nude mice showed that intraperitoneal injection of JIMB01 at 15mg/kg (with seven injections at 4-day intervals) significantly inhibited the growth of a human hepatocarcinoma (BEL-7402) by 66% in tumor volume (P=0.01), at least compatible to the inhibition by vincristine (43% inhibition), indicating good bioavailability of the compound in the circulation. Side-effects of the compound were not observed, and the body weight of the treated mice remained stable during the 4-week treatment. Since JIMB01 is a small compound, targets a specific molecule in tumor cells, and has promising activity against human hepatocarcinoma in vivo, we believe JIMB01 merits consideration for further investigation.

Moderate progress for ovarian cancer in the last 20 years: prolongation of survival, but no improvement in the cure rate

Although ovarian cancer treatment has advanced in the last 20 years, long-term survival remains stable. The purpose of this study was to determine whether survival has improved in line with treatment advances in a population-based prospective cohort of ovarian cancer patients (1978-1997, with a follow-up through to 2000). The 10-year overall survival rate for cancer patients was similar before and after 1988: 32.2% (n=1661) and 34.4% (n=2089). For patients after 1988, a 12-month prolongation of median survival was observed. In terms of stage according to the International Federation of Gynecology and Obstetrics (FIGO), only FIGO I and FIGO II patients showed, in addition to a prolongation in survival, an absolute improvement of 12.9 and 12.6% after 5 years and of 13.2 and 8.6% after 10 years. This hardly affected the survival of the total sample. For the most frequent stage FIGO III patients and for FIGO IV patients, a prolongation in survival time, but no improvement in survival rate, was seen after five or 10 years. The progress in FIGO I and II patients may be due to more accurate staging. More effective chemotherapy may also explain some of the improvement. The prolongation in FIGO-stages III-IV may be due to more radical surgery. Patient selection criteria, not only the treatment modalities, may be responsible for the superior results reported in clinical trials. Cancer registries are important for evaluating the quality of healthcare delivery.

First-line treatment for advanced ovarian cancer: paclitaxel, platinum and the evidence

Four large randomised trials of paclitaxel in combination with platinum against a platinum-based control treatment have now been published in full, representing around 88% (3588 out of 4057) of patients randomised into the eight known trials of this question. There is substantial heterogeneity in the results of these four trials. Four main explanations for this heterogeneity have been proposed: differences in the extent and timing of 'crossover' to taxanes in the control groups; differences in the types of patient included; differences in the effectiveness of the research regimens used; differences in the effectiveness of the control regimens used. In this study we examine whether any of these explanations is consistent with the pattern of results seen in these trials. Each explanation suggests that a particular characteristic of each trial was responsible for the results observed. For each explanation the trials were split into groups according to that characteristic, in order to partition the total heterogeneity into that seen 'within' and 'between' groups of trials. If a particular explanation was consistent with the pattern of results, we would expect to see relatively little heterogeneity within each group of trial results viewed in this way, with most of the heterogeneity being between groups which are dissimilar with respect to the key characteristic. Heterogeneity 'within' and 'between' groups was formally compared using the F-ratio. If any explanation appeared to be consistent with the results of the trials, it was considered whether the explanation was also consistent with other evidence available about these regimens. Only one explanation appeared to be consistent with the pattern of results seen in these trials, and that was differences in effectiveness of the control arms used in these trials. This suggests that the very positive results in favour of paclitaxel/cisplatin seen in two of the trials may have been due to the use of a suboptimal control arm. There is no direct evidence about the relative effectiveness of the control arms used in these trials, but indirect evidence is consistent with the conclusion that the cyclophosphamide/cisplatin regimen used in two of the trials may be less effective than the control regimens used in the other trials. Specific concerns about the choice of a cyclophosphamide/cisplatin control arm in the first of these trials to report were raised before the results of the other trials were known, i.e. before any heterogeneity had been observed. Further investigation of this question would be useful. In the meantime, given all of the randomised evidence on the efficacy and toxicity associated with the regimens used in these trials, we conclude that single agent carboplatin is a safe and effective first-line treatment for women with advanced ovarian cancer.

Paclitaxel plus carboplatin versus standard chemotherapy with either single-agent carboplatin or cyclophosphamide, doxorubicin, and cisplatin in women with ovarian cancer: the ICON3 randomised trial

BACKGROUND

Previously, we have shown that the combination of cyclophosphamide, doxorubicin, and cisplatin (CAP) and single-agent carboplatin produce similar survival and progression-free survival rates in women with ovarian cancer. Subsequently, paclitaxel combined with platinum has become a widely accepted treatment for the disease. We aimed to compare the safety and efficacy of paclitaxel plus carboplatin with a control of either CAP or carboplatin alone.

METHODS

Between February, 1995, and October, 1998, we enrolled 2074 patients from 130 centres in eight countries. Women were randomly assigned paclitaxel plus carboplatin or control, the control (CAP or single-agent carboplatin) being chosen by the patient and clinician before randomisation. The primary outcome measure was overall survival. Secondary outcomes were progression-free survival and toxicity. Analysis was by intention to treat.

FINDINGS

With a median follow-up of 51 months, 1265 patients had died, and survival curves showed no evidence of a difference in overall survival between paclitaxel plus carboplatin and control (hazard ratio 0.98, 95% CI 0.87-1.10, p=0.74). The median overall survival was 36.1 months on paclitaxel plus carboplatin and 35.4 months on control (difference 0.7 months, 95% CI -3.6 to 4.7). 1538 patients had progressive disease or died, and again, Kaplan-Meier curves showed no evidence of a difference between the groups (hazard ratio 0.93, 95% CI 0.84-1.03, p=0.16). Median progression-free survival was 17.3 months on paclitaxel plus carboplatin and 16.1 months on control (difference 1.2 months, 95% CI -0.5 to 2.8). Paclitaxel plus carboplatin caused more alopecia, fever, and sensory neuropathy than carboplatin alone, and more sensory neuropathy than CAP. CAP was associated with more fever than paclitaxel plus carboplatin.

INTERPRETATION

Single-agent carboplatin and CAP are as effective as paclitaxel plus carboplatin as first-line treatment for women requiring chemotherapy for ovarian cancer. The favourable toxicity profile of single-agent carboplatin suggests that this drug is a reasonable option as first-line chemo therapy for ovarian cancer.

Chemotherapy for advanced epithelial ovarian carcinoma

Advanced epithelial ovarian cancer (AOC) is the most common clinical presentation of ovarian cancer. Virtually all patients will require some form of chemotherapy with curative or palliative intent. Prognostic factors, first- and second-line therapy, as well as experimental approaches for AOC are reviewed.

Current and future potential roles of the platinum drugs in the treatment of ovarian cancer

The discovery of cisplatin more than two decades ago was the most important therapeutic advance in the treatment of ovarian cancer. Today, cisplatin or carboplatin in combination with paclitaxel is the most commonly used first-line treatment for patients with advanced ovarian cancer. Although platinum drugs remain a critical component of chemotherapy in this type of cancer, cumulative toxicities can limit their use. These toxicities include nephrotoxicity, neurotoxicity and ototoxicity with cisplatin and myelosuppression with carboplatin. Although these adverse events can often be managed, the interventions themselves can complicate and add to the costs of treatment. Importantly, acquired resistance to traditional platinum drugs often develops in patients with ovarian cancer and can limit the usefulness of these drugs. Research into new platinum drugs has focused on identifying compounds with improved tolerability profiles and, importantly, those which can circumvent mechanisms of platinum resistance. New platinum drugs currently under development that are showing promise in ovarian cancer include oxaliplatin, nedaplatin, satraplatin, BBR3464 and ZD0473. If the encouraging in vitro activity shown by new compounds, such as ZD0473 and BBR3464, translates into efficacy in the clinic, they may offer an extended spectrum of activity which includes patients with ovarian cancer resistant to the classical platinum drugs.

p53 gene status and response to platinum/paclitaxel-based chemotherapy in advanced ovarian carcinoma

PURPOSE

The p53 gene plays a critical role in cellular response to DNA damage and has been implicated in the response to platinum compounds in ovarian carcinoma patients. Because taxanes could induce p53-independent apoptosis, we assessed the relevance of p53 gene status to response in ovarian carcinoma patients receiving paclitaxel and platinum-containing chemotherapy.

PATIENTS AND METHODS

Forty-eight previously untreated patients with advanced disease received standard paclitaxel/platinum-based chemotherapy. In tumor specimens collected at the time of initial surgery, before therapy, p53 gene status and expression were examined by single-strand conformation polymorphism, sequence analysis, and immunohistochemical analysis. Microsatellite instability analysis was performed on available samples from 30 patients.

RESULTS

Thirty-four (71%) of the 48 patients had a clinical response. Pathologic complete remission was documented in 13 (27%) of 48 patients. p53 mutations were detected in 29 (60%) of 48 tumors. Among the patients with mutant p53 tumors, 25 patients (86%) responded to chemotherapy. Only nine (47%) of 19 patients with wild-type p53 tumors responded to the same treatment. The overall response rate and the complete remission rate were significantly higher among patients with mutant p53 tumors than among patients with wild-type p53 tumors (P: =.008). Most of the tested tumors not associated with complete remission (10 of 12 tumors) were also characterized by microsatellite instability. The complete remission rate was higher among patients with tumors without microsatellite instability (five of seven patients).

CONCLUSION

In contrast to the limited efficacy of treatment with paclitaxel in combination with standard platinum doses against wild-type p53 ovarian tumors, patients with mutant p53 ovarian tumors were more responsive to paclitaxel-based chemotherapy. The pattern of response to chemotherapy containing paclitaxel is different from that associated with high-dose cisplatin therapy. Determining p53 mutational status can be useful in predicting therapeutic response to drugs effective in ovarian carcinoma.

Phase II clinical trials of cisplatin-then-paclitaxel and paclitaxel-then-cisplatin in patients with previously untreated advanced epithelial ovarian cancer

PURPOSE

To examine the activity and safety of two sequentially scheduled chemotherapy regimens comprising four cycles of paclitaxel (pctx) 200 mg/m2/3 hours then four cycles ofcisplatin (cisDDP) 100 mg/m2, and vice versa, in patients with previously untreated advanced ovarian cancer.

PATIENTS AND METHODS

Between January 1994 and February 1996, we recruited 30 patients to the pctx-then-cisDDP regimen and 29 to cisDDP-then-pctx, in parallel phase II trials.

RESULTS

Both regimens were predictably active with responses seen in 22 of 30 patients (OR 74%; CR 27%, PR 47%) treated with pctx-then-cisDDP, as against 13 of 21 patients (OR 62%; CR 38%, PR 24%) treated with cisDDP-then-pctx. The OR rate to four cycles of pctx (induction) was 43%, with 27% disease progression; the OR to four cycles of cisDDP (induction) was 57%, with 5% progression. However, progression rates across both induction and consolidation phases were 16% (pctx-then-cisDDP) and 29% (cisDDP-then-pctx). Both regimens were unacceptably neurotoxic. II patients suffering grade 3 sensory neurotoxicity (5 on pctx-then-cisDDP, 6 on cisDDP-then-pctx) and 20 having grade 3 deafness (9 on pctx- then-cisDDP, 11 on cisDDP-then-pctx).

CONCLUSION

The activity of these sequential regimens justifies their further development using the less neurotoxic platinum analogue carboplatin, perhaps combining paclitaxel with other platinum non-cross resistant drugs.

Growth-inhibiting effects of taxol on human liver cancer in vitro and in nude mice

AIM: To investigate the effects of taxol on SMMC-7721 human hepatoma and its mechanisms.

METHODS: In vitro cell growth was assessed by trypan blue exclusion method. Experimental hepatoma model was established by seeding SMMC-7721 cells subcutaneously into Balb/c (nu/nu) nude mice. In vivo tumor growth was determined by measurement of tumor diameter with Vernier calipers. The syntheses of DNA, RNA and protein were analyzed by incorporation of ³H-thymidine, ³H-uridine and ³H-leucine respectively. Using light and electron microscopes to observe the morphological changes of cells including mitosis and apoptosis.

RESULTS: Taxol was effective against SMMC-7721 human hepatoma cell growth in the ranges of 2.5 nmol/L-10 nmol/L- with mitotic arrest and apoptosis in vitro. DNA, RNA and protein syntheses in cells were also obviously suppressed by in vitro treatment of taxol for 72 h. Taxol at 2.5 nmol/L reduced ³H-thymidine uptake to about 34% of the control value (P ＜ 0.05). Increasing the dose of taxol to 20 nmol/L resulted in a greater decrease in ³H-thymidine incorporation to 60% of the control value (P ＜ 0.01). At a concentration of 20 nmol/L, the ³H-uridine and ³H-leucine uptakes were reduced to 52% (P ＜ 0.05) and 63% (P ＜ 0.01), respectively. In vivo, taxol significantly inhibited SMMC-7721 tumor growth at 10 mg/kg, i.p. once daily for 10 d. A more than 90% decrease in tumor volume was observed by day 11 (P ＜ 0.01) similarly with mitotic arrest and cell apoptosis.

CONCLUSION: Taxol has a marked anticancer activity in SMMC-7721 human hepatoma both in vitro and in nude mice. Its mechanisms might be associated with mitotic arrest, subsequently, apoptosis of the hepatoma cells. No obvious toxicity was observed with in vivo administration of taxol.

Novel suicide ligands of tubulin arrest cancer cells in S-phase

It is presently accepted that the mechanism of action for all anti-tumor tubulin ligands involves the perturbation of microtubule dynamics during the G2/M phase of cell division and subsequent entry into apoptosis [1]. In this report, we challenge the established dogma by describing a unique mechanism of action caused by a novel series of tubulin ligands, halogenated derivatives of acetamido benzoyl ethyl ester. We have developed a suicide ligand for tubulin, which covalently attaches to the target and shows potent cancericidal activity in tissue culture assays and in animal tumor models. These compounds target early S-phase at the G1/S transition rather than the G2/M phase and mitotic arrest. Bcl-2 phosphorylation, a marker of mitotic microtubule inhibition by other tubulin ligands was dramatically altered, phosphorylation was rapid and biphasic rather than a slow linear event. The halogenated ethyl ester series of derivatives thus constitute a unique set of tubulin ligands which induce a novel mechanism of apoptosis.

Combination photoimmunotherapy and cisplatin: effects on human ovarian cancer ex vivo

BACKGROUND

Patients with ovarian cancer that is clinically resistant to cisplatin-based chemotherapy have little hope of a cure of their disease. Photoimmunotherapy, which involves the antibody-targeted delivery of a nontoxic photosensitizer that is activated to a cytotoxic state with visible light, may offer a new treatment option. Photoimmunotherapy may be applied intraperitoneally to target disseminated tumor. We tested the hypothesis that this treatment in combination with cisplatin potentiates cytotoxicity in ovarian cancer cell lines and primary cultures of human tumors.

METHODS

Five human cancer cell lines (ovarian and breast) and 19 primary cultures were studied. The primary cultures were from solid and ascites tumor samples obtained from 14 patients with ovarian cancer who were undergoing primary surgery. The photosensitizer chlorin e(6) was conjugated to the F(ab')(2) fragment of the murine monoclonal antibody OC-125, which is directed against the antigen CA 125. Cytotoxicity was measured by the microculture tetrazolium assay. Treatments consisted of cisplatin alone, photoimmunotherapy alone, and photoimmunotherapy followed by cisplatin. The fractional product method was used to assess synergy in treatment effects. Ex vivo cultured human cells exhibiting 80% or greater survival at cisplatin concentrations of 10 microM for 24 hours were defined as cisplatin resistant for this study.

RESULTS

When all cell types (cisplatin sensitive and cisplatin resistant) were considered together, combination treatment yielded cytotoxicity that was, on average, 6.9 times (95% confidence interval = 1.86-11.94) greater than that of cisplatin alone (two-sided P =.023). Cisplatin-resistant cells showed a synergistic effect of the two treatments (two-sided P =.044), while cisplatin-sensitive cells showed an additive effect.

CONCLUSION

These ex vivo data suggest that platinum resistance in human ovarian cancer cells may be reversible by pretreatment with OC-125-targeted photoimmunotherapy. Further studies are required to confirm the efficacy of this approach in vivo.